Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kyuro Sasaki Last modified date:2019.07.09

Professor / Resource System Engineering / Department of Earth Resources Engineering / Faculty of Engineering


Papers
1. Ichhuy Ngo, Falan Srisuriyachai, Kyuro Sasaki, Yuichi Sugai, Ronald Nguele, Effects of reversibility on Enhanced Oil Recovery using Sodium Dodecylbenzene Sulfonate (SDBS), Journal of the Japan Petroleum Institute, 10.1627/jpi.62.188, 62, 4, 188-198, 2019.07, [URL], Reduction of interfacial tension (IFT) between residual crude oil and formation fluids in oil reservoirs is the key to enhanced oil recovery (EOR) by surfactant flooding. However, adsorption of injected surfactant on minerals in the oil-bearing rock matrix reduces the effectiveness of this method. The present study investigated the effects of surfactant adsorption and desorption in the rock matrix on the oil recovery ratio achieved by surfactant-EOR. Sodium dodecylbenzene sulfonate (SDBS), a common surfactant in EOR, was used with Berea sandstone samples (rock particles and cores) as adsorbent. Adsorption of SDBS in the samples increased with concentration, and the static saturated amount was 0.9 mg-SDBS/g-rock for 1.0 wt% SDBS-water solution. If brine (1.0 wt% salinity) was injected after saturated adsorption of SDBS in the core, 83 % of adsorbed SDBS was desorbed into the brine (the reversibility effect). To clarify the reversibility effect in oil reservoirs, field scale numerical simulations were conducted for a typical 5 spot model (area: 180 m × 180 m, thickness: 60 m) using core-flooding data reported previously. By introducing the reversibility model into the simulations on of surfactant flooding injection of slugs of 0.1 PV and 0.3 PV into the initial reservoir, oil recovery factor showed differences of 2.3 % and 2.9 % compared to without the model, respectively. Injection of the surfactant solution after water-flooding caused a difference of only 0.4 %..
2. Cong Wang, O. S. Alade, K. Sasaki, Yuichi Sugai, Experimental and simulation studies on gasification characteristics of a low-rank coal by rapid heating under CO2-rich condition, Journal of Applied Research and Technology, 16, 4, 255-266, 2019.06, In this investigation, an environmentally benign and efficient way for gasification of low-rank coal under CO2 rich condition, rapid heating, and high pressure was investigated. Series of experimental and simulation studies were carried out to compare the combustion characteristics of the Shandong (SD) low rank coal and Datong (DT) bituminous coal. It was found that the gasification potential of the SD coal sample was higher than that of the DT coal sample under the conditions investigated. A gasification model was developed and validated to predict the gasification characteristics of the low rank coal based on the experimental and the gasification kinetic parameters. It was found that the gasification conditions resulting in effective gasification of the low rank coal (in terms of CH4, CO and H2 gases production) are 100% CO2 concentration, 37.5 J/s heating rate, and 0.5 – 1 MPa pressure range..
3. Ichhuy Ngo, Falan Srisuriyachai, K. Sasaki, Yuichi Sugai, Ronald Nguele, Effects of reversibility on enhanced oil recovery using Sodium Dodecylbenzene Sulfonate (SDBS), Journal of the Japan Petroleum Institute, 10.1627/jpi.62.188, 62, 4, 188-198, 2019.07, Reduction of interfacial tension (IFT) between residual crude oil and formation fluids in oil reservoirs is the key to enhanced oil recovery (EOR) by surfactant flooding. However, adsorption of injected surfactant on minerals in the oil-bearing rock matrix reduces the effectiveness of this method. The present study investigated the effects of surfactant adsorption and desorption in the rock matrix on the oil recovery ratio achieved by surfactant-EOR. Sodium dodecylbenzene sulfonate (SDBS), a common surfactant in EOR, was used with Berea sandstone samples (rock particles and cores) as adsorbent. Adsorption of SDBS in the samples increased with concentration, and the static saturated amount was 0.9 mg-SDBS/g-rock for 1.0 wt% SDBS-water solution. If brine (1.0 wt% salinity) was injected after saturated adsorption of SDBS in the core, 83 % of adsorbed SDBS was desorbed into the brine (the reversibility effect). To clarify the reversibility effect in oil reservoirs, field scale numerical simulations were conducted for a typical 5 spot model (area: 180 m × 180 m, thickness: 60 m) using core-flooding data reported previously. By introducing the reversibility model into the simulations on of surfactant flooding injection of slugs of 0.1 PV and 0.3 PV into the initial reservoir, oil recovery factor showed differences of 2.3 % and 2.9 % compared to without the model, respectively. Injection of the surfactant solution after water-flooding caused a difference of only 0.4 %.
4. Wang Cong,Olalekan S. Alade,Kyuro Sasaki, Yuichi Sugai, Experimental and Simulation Studies on Gasification Characteristics of A Low-rank Coal by Rapid Heating under CO2-rich Condition, Journal of Applied Research and Technology, 16, 4, 255-266, 2019.06, [URL], In this investigation, an environmentally benign and efficient way for gasification of low-rank coal under CO2 rich condition, rapid heating, and high pressure was investigated. Series of experimental and simulation studies were carried out to compare the combustion characteristics of the Shandong (SD) low rank coal and Datong (DT) bituminous coal. It was found that the gasification potential of the SD coal sample was higher than that of the DT coal sample under the conditions investigated. A gasification model was developed and validated to predict the gasification characteristics of the low rank coal based on the experimental and the gasification kinetic parameters. It was found that the gasification conditions resulting in effective gasification of the low rank coal (in terms of CH4, CO and H2 gases production) are 100% CO2 concentration, 37.5 J/s heating rate, and 0.5 – 1 MPa pressure range..
5. Olalekan S. Alade,Dhafer Al Shehri, Mohamed Mahmoud,Kyuro Sasaki, Yuichi Sugai, Evaluation of Laminar Flow of Surfactant-stabilized Bitumen-in-water Emulsion in Pipe using Computational Fluid Dynamics: Effects of Water Content and Salinity, Journal of Dispersion Science and Technology, 10.1080/01932691.2019.16, 40, 1-12, 2019.05, [URL], Laminar flow of oil-in-water (O/W) emulsion in a horizontal pipe has been simulated to quantify the effect of salinity of aqueous phase and water content on flow characteristics using computational fluid dynamics (CFD). Bitumen was dispersed in aqueous solution containing surfactant at different NaCl concentrations and water contents. Rheological parameter was obtained from the viscosity-shear rate profiles of the fluid. Numerical modeling and simulation was performed using a finite element simulation software. The case was simplified by considering the O/W emulsion as a stable, pseudo-homogeneous (single-phase) fluid within the conditions investigated. At flow reference temperature, Tref = 30 °C, the pressure drop obtained from emulsion with 30% water content was 931 Pa, compared to 84.6 Pa which was obtained from 50% water content (i.e. reference fluid without NaCl). In addition, the pressure drop of 239 Pa, 142 Pa, 124 Pa, and 82.9 Pa was obtained from O/W emulsion samples containing 70000 ppm, 40000 ppm, 20000 ppm, and 10000 ppm salinity in the aqueous phase, respectively. Furthermore, the maximum dynamic viscosity imposed by the fluid, was calculated as ≈81000 cP for the sample containing 30% water content compared to ≈14000 cP from the reference fluid. The dynamic viscosity obtained from 70000 ppm salinity content was ≈34000 cP compared to ≈20000 cP, ≈16000 cP, and ≈13000 cP calculated for 40000 ppm, 20000 ppm, and 10000 ppm salinity, respectively. Moreover, large reduction in pressure drop (99%) and dynamic viscosity (60–90%), regardless of the water content and salinity were obtained from the simulation..
6. Xiaochen Yang, Kyuro Sasaki, Xiaoming Zhang, Yuichi Sugai, Permeability Estimate of Underground Long-wall Goaf from P-wave Velocity and Attenuation by Lab-scale Experiment on Crushed Rock Samples, Journal of Applied Geophysics, 10.1016/j.jappgeo.2018.09.009, 159, 785-794, 2018.12, [URL], In this study, forty-five crushed rock samples were formed from rock and coal particles of different sizes to simulate the crushed and fragmented condition of a goaf area in an underground coal mine. The porosity (φ) range of the crushed samples was based on field observations in actual goafs. The permeability (k) was measured by reducing the size of the fragments of the actual goaf to lab-scale particles. Ultrasonic wave velocity (VPG) and attenuation (β) were measured for different porosities, particle sizes and frequencies. The ratio of the seismic wavelength and particle size was adjusted to match that of the parameters in the goaf. The results showed that the measured permeability conformed to the Kozney-Carman (KC) equation with a percolation threshold porosity of 0.06. The permeability of the crushed rock was dependent on φ4. The variations of the seismic velocity (η) and attenuation (ξ) were defined based on the ratio of the seismic parameters of the crushed rock and intact rock. η showed a linear relationship with the square root of the tortuosity (τ) for τ = 5–10. ξ showed an approximately linear relationship with the porosity part of the KC equation. An empirical equation is proposed based on the KC equation, involving the seismic velocity, attenuation and particle size. The estimated permeability based on the modified KC equation showed good agreement with the measured data. The permeability of the actual goaf was estimated as 1.0 × 104–6.5 × 105 d based on the rock properties in the goaf..
7. Olalekan S. Alade, Kyuro Sasaki, Yuichi Sugai, Kojo T. Konadu, Eric O. Ansah, Bayonile Ademodi, Ryo Ueda, Kinetics of Thermal Degradation of A Japanese Oil Sand, Egyptian Journal of Petroleum, 10.1016/j.ejpe.2017.08.001, 27, 4, 505-512, 2018.12, [URL], Thermal degradation characteristics of a Japanese oil sand at different heating rates (10, 20, and 30 °C/min), and 30 ml/min air flow rate have been investigated. The kinetic parameters have been calculated based on three stages of weight loss and/or the conversion of the sample. These include, stage 1 (SI): volatilization of moisture content and the light hydrocarbon (20–227 °C), stage 2 (SII): combustion of heavy hydrocarbon (227–527 °C), and stage 3 (SIII): oxidative decomposition of carbonaceous organic matter (502–877 °C). The results showed that the rate of change of the oil sand conversion with time View the MathML sourcedαdt was affected by the heating rate. The time taken by the system to reach 0.99 conversion was observed as 85, 50, and 35 min at the heating rates of 10, 20, and 30 °C/min, respectively. The frequency factor, A, at SI was between 0.09 and 0.54 min−1, while the activation energy, Ea, was 11.2–12.5 KJmol−1 (the percentage weight loss, Wt, was 0–3.6 %w/w; and the conversion, α, was 0–0.2.). At SII, the values of A and Ea were 2.1–5.5 min−1 and 17.6–19 KJmol−1, respectively (Wt = 3.1–15.88 %w/w; α = 0.17–0.86.). The value of A at SIII was 5.5E11–1.1E13 min−1, while Ea was 160–200 KJmol−1 (Wt = 15.33–17.99 %w/w; and α = 0.84–0.99)..
8. Zhen Hao Lim, Hikmat Said Al Salim, Norida Ridzuan, Ronald Nguele, Kyuro Sasaki, Effect of Surfactants and Their Blend with Silica Nanoparticles on Wax Deposition in a Malaysian Crude Oil, Petroleum Science, 10.1007/s12182-018-0241-2, 1-14, 2018.07, The present study investigated the wax deposition tendencies of a light Malaysian crude oil (42.4 API), and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the wax inhibition research revolved around polymeric wax inhibitors, which cause environmental issues, we highlighted the potential of surfactants and their blend with SiO2 nanoparticles as wax deposition inhibitors. Different surfactants including oil-based, silane-based, Gemini and bio-surfactants were considered as primary surfactants. The primary surfactants and their respective blends at a concentration of 400 ppm were screened as wax inhibitor candidates using cold finger apparatus. The screening results showed a significant influence on the paraffin inhibition efficiency on wax deposition by using 400 ppm of silane-based surfactant, which decreased the wax deposition up to 53.9% as compared to that of the untreated crude oil. The inhibition efficiency among the silane-based surfactant (highest) and bio-surfactant (lowest) revealed an appreciable difference up to 36.5%. Furthermore, the wax from the treated sample was found to deposit in a thin gel-like form, which adhered inadequately to the surface of the cold finger. A further investigation by blending the 400 ppm silane-based surfactant with a 400 ppm SiO2 nanoparticle suspension in a load ratio of 3:1 found that the wax inhibition decreased up to 81% as compared to the scenario when they were not added. However, we have shown that the synergy between the silane-based surfactant and the nanoparticles is influenced by the concentration and load ratio of surfactant and nanoparticles, residence time, differential temperature and rotation rate..
9. Xiaochen Yang, Kyuro Sasaki, Xiaoming Zhang, Yuichi Sugai, Experimental Study on Seismic Attenuation and Permeability of Large Porosity Rock, Journal of Geoscience and Environment Protection, 10.4236/gep.2018.65007, 6, 80-90, 2018.05, [URL], The large porosity areas widely present in the underground resulting from natural hazards or artificial damages. The porosity and permeability are suggested to be capable of estimating the mechanical and air flow conditions inside the porous layer in the underground. To accurately measure the porosity and permeability in the porous area is imperative. To address this issue, we experimentally modeled some porous samples in large porosities by using sandstone particles sieved to different sizes. Ultrasonic was employed to apply on the porous sandstone samples to characterize the seismic velocity and attenuation. Permeability was also measured simultaneously to find a correlation with the porosity. The results showed the seismic attenuation decrease as the reduction of frequency and increasing particle size at the same porosity. Seismic attenuation was strongly correlated to porosity and particle size. Velocity showed a good relationship with the porosity change. Permeability was highly dependent on the particle size especially in the higher porosity range. The results indicated that it is possible to find a relationship between the permeability and seismic attenuation via the porosity and particle size..
10. Eric O. Ansah, Yuichi Sugai, Kyuro Sasaki, Modeling Microbial-induced Oil Viscosity Reduction: Effect of Temperature, Salinity and Nutrient Concentration, Petroleum Science and Technology, 10.1080/10916466.2018.1463253, 1-7, 2018.05, [URL], This research simulated oil recovery with emphasis on oil viscosity reduction by direct microbe action and metabolites; predicted hydrogeochemical reactions involved with nutrient – brine interaction in reservoirs. PHREEQC was used to simulate reactions between the reservoir brine and nutrient minus microbe. Hitherto, UTCHEM was employed for the enhancement of oil viscosity by assuming production of gases and by the direct microbe action. The model depicted the precipitation of calcite plus dissolution of k-feldspar combined with the evolution of CO2 and CH4 influenced by temperature and pH. Oil recovery was directly proportional to salinity reduction and increasing nutrient concentration..
11. Hiroki Matsuda, Takafumi Yamakawa1, Yuichi Sugai, Kyuro Sasaki, Numerical Prediction of Seabed Subsidence with Gas Production from Offshore Methane Hydrates by Hot-Water Injection Method, International Journal of Petroleum and Petrochemical Engineering, 10.20431/2454-7980.0401004, 4, 1, 18-32, 2018.01, [URL], Seabed subsidence is studied by comparing experimental data with the results of a numerical model for gas production from an offshore methane hydrate (MH) reservoir using the hot-water injection method. To predict seafloor displacement, geo-mechanical reservoir models, such as the consolidation–permeability compound model, are required to simulate MH dissociation and consolidation by depressurization in the MH reservoir. In this study, we constructed a field-scale model of gas production from a MH reservoir induced by hot-water injection using dual horizontal wells. Compared with the depressurization method, this method required less depressurization to produce the same amount of gas with pressure drawdown up to 10MPa. This causes less seabed subsidence; therefore, the hot-water injection method is a more environmentally friendly gas-production method for offshore MH reservoirs..
12. Kreangkrai Maneeintr, Monthicha Rawangphai, Kyuro Sasaki, Evaluation for Offshore Carbon Dioxide Geological Storage Potential in the Gulf of Thailand, Energy Procedia, 10.1016/j.egypro.2017.12.234, 142, 3486-3491, 2017.12, [URL], Currently climate change is one of the most concern problems because of an increase in the amount of carbon dioxide (CO2) in the atmosphere. This gas comes from the industries like power generation. Carbon capture and storage (CCS) is the practical technology to mitigate CO2 especially geological storage. In Thailand, the main potential of geological storage is in the Gulf of Thailand especially in the oil and gas fields. However, the research on this in Thailand is scarce. Consequently, this work is focusing on the simulation of CO2 geological storage in the formations of oil and gas reservoirs in the Gulf of Thailand. The fracture pressure and the storage capacity have been estimated. Also, the pressure buildup and plume migration have been simulated with various conditions by using real geological data in the area. CO2 injection is used from 1,000-4,000 tons per day with the depth from 2,000-2,500 meters and the results are studied for 50 years as a monitoring period. The results present that with the actual formation characteristics, CO2 storage in this area has potential. Moreover, pressure buildup and plume migration are presented the storage and monitoring for 50 years. As a fundamental knowledge, this study can contribute to CO2 storage in an offshore area in Thailand..
13. Salmawati, Kyuro Sasaki, Yuichi Sugai, Estimating Surface CO2 Flux Based on Soil Concentration Profile, British Journal of Environment & Climate Change, 10.9734/BJECC/2017/38328, 7, 4, 214-222, 2017.12, [URL], A total of seven measurements of soil CO2 concentration profile showed that the CO2 concentration increased with soil depth and it was fitted with logarithmic trend (R2 = 0.981 in average). A range of CO2 concentration values was measured at each depth, i.e., 1300 to 8700 ppm at 0.1 m depth; 2500 to 10800 ppm at 0.2 m depth; 4200 to 13200 ppm at 0.3 m depth..
14. Yuta Yoshioka, Kyuro Sasaki, Kyoichi Takatsu, Yuichi Sugai, Screening of Major Chemical Reactions in In-Situ Combustion Process for Bitumen Production from Oil Sands Reservoirs, International Journal of Petroleum and Petrochemical Engineering, 10.20431/2454-7980.0304008, 3, 4, 82-92, 2017.12, [URL], In this study, screening of major chemical reactions used for numerical simulations on in-situ combustion (ISC) process has been investigated to produce bitumen from oil sands reservoir. Bitumen productions from oil sands reservoirs have been successfully carried out using thermal method, such as Steam Assisted Gravity Drainage (SAGD), but operation cost including water treatment has been a big issue to continue the bitumen production. ISC has been expected to provide high recovery, low cost and saving water. However, combustion chemical reactions and their kinetic parameters for bitumen have not been completely fixed. Some numerical simulations on the combustion tube experiments with Athabasca bitumen were conducted to construct the chemical reactions. But, screening to pick up major chemical reactions is necessary to carry out a field size reservoir simulation by reducing of CPU processing time with less number of the chemical reactions. In this study, it was confirmed that the model presented Yang and Gates (2009) could simulate the experimental results of combustion tube test better than other models. Three major reactions, defined as low temperature oxidation and high temperature oxidation (LTO and HTO), were screened based on numerical simulations by extracting a reaction one by one from the model consists eight reactions. The field scale 3D numerical simulation on THAI (Toe-to-Heel Air Injection) process, an expected ISC technology to produce bitumen, has been carried out successfully for a typical oil sands reservoir by using the three reactions. Furthermore, the comparisons of numerical simulation results have been conducted between THAI and SAGD methods..
15. Yaguba Jalloh, Mustapha Olajiday Thomsa, Kyuro Sasaki, Groundwater Assessment through an Integrated Approach using GIS and Electrical Resistivity Technique - A Case Study from the Bullom Group of Sediments in Sierra Leone, Journal of Environmental and Analytical Toxicology, 10.4172/2161-0525.1000523, 7, 6, 1-7, 2017.11, [URL], Electrical Resistivity in conjunction with Geographic Information System (GIS) techniques have been widely used in groundwater resource management. In this research, Vertical Electric Sounding (VES), an Electrical Resistivity method, was integrated with GIS to delineate geo-electric characteristics and evaluate groundwater potential of the Bullom group of sediments in Sierra Leone. For this assessment, a total of 5 vertical electrical sounding stations were established within the site. The Schlumberger electrode configuration and the expanding procedure were used for data acquisition. The VES curves generated were interpreted using partial curve matching. The depth sounding interpretation results were used to generate geo-electric sections from which the aquifer was delineated. The aquifer revealed four subsurface layers which comprises of sandy topsoil, clayey sand which acts as aquitard and sandy gravel (confine aquifer) that serves as a source of portable water in the study area. A GIS model was then developed to locate the suitable groundwater prospective zones which reveals the average depth to groundwater to be between 10 m to 30 m. This research concluded that the boreholes were sited in high conductivity zones in VES layers 1, 2, 3 and 4 as they contain probable aquifers with good yield..
16. Yaguba Jalloh, Kyuro Sasaki, Mustapha Olajiday Thomsa, Groundwater Assessment through an Integrated Approach Using GIS and Electrical Resistivity Technique: A Case Study from the Bullom Group of Sediments in Sierra Leone, Journal of Environmental & Analytical Toxicology, 10.4172/2161-0525.1000523, 7, 6, 523-1-523-7, 2017.11, Electrical Resistivity in conjunction with Geographic Information System (GIS) techniques have been widely used in groundwater resource management. In this research, Vertical Electric Sounding (VES), an Electrical Resistivity method, was integrated with GIS to delineate geo-electric characteristics and evaluate groundwater potential of the Bullom group of sediments in Sierra Leone. For this assessment, a total of 5 vertical electrical sounding stations were established within the site. The Schlumberger electrode configuration and the expanding procedure were used for data acquisition. The VES curves generated were interpreted using partial curve matching. The depth sounding interpretation results were used to generate geo-electric sections from which the aquifer was delineated. The aquifer revealed four subsurface layers which comprises of sandy topsoil, clayey sand which acts as aquitard and sandy gravel (confine aquifer) that serves as a source of portable water in the study area. A GIS model was then developed to locate the suitable groundwater prospective zones which reveals the average depth to groundwater to be between 10 m to 30 m. This research concluded that the boreholes were sited in high conductivity zones in VES layers 1, 2, 3 and 4 as they contain probable aquifers with good yield..
17. Ronald Nguele, Kyuro Sasaki, Yuichi Sugai, Hikmat Said-Al Salim, Ryo Ueda, Mobilization and Displacement of Heavy Oil by Cationic Microemulsions in Different Sandstone Formations, Journal of Petroleum Science and Engineering, 10.1016/j.petrol.2017.07.032, 157, 1115-1129, 2017.08, [URL], Herein is presented a hybrid production scheme that considered the injection of gel type-microemulsions to mobilize and to displace stranded heavy oil. The present work investigated not only the flow of proposed microemulsions during their journey through the sandstone cores, but also evaluates the influence of flooding conditions on their displacement efficiency. The proposed formulated were prepared from micellar slugs, which were found efficient in solubilizing for heavy oils especially when they were prepared from a cationic Gemini surfactant with a longer alkyl chain. A series of coreflood tests showed that the injection of formulated microemulsions in a conventional water-flooded Berea sandstones recovered about 20.3 and 31.6% of initial-oil-in place (IOIP). The same formulations, injected in an artificially fractured and heterogeneous sandstones, yielded an oil recovery of 6.4 and 8.4% of IOIP respectively. Regardless the nature of the network of oil-bearing matrix, the heaviest formulation, that was the microemulsion prepared from the cationic Gemini surfactant with the longest alkyl chain, stood as a better displacing agent compared to its counterpart prepared from the a short alkyl chain. The mechanism of oil production was found subsequent to a reduction in viscous forces (order of 10−10), which itself was altered by the chemistry inherent to the propagation of microemulsion and that of the formation brines. These concomitant mechanisms prompt the wettability alteration of the sandstone from mixed-wet to water-wet for conventional sandstone and to strongly-water unconventional cores. Also, the formation of sludgy materials, subsequent to microemulsion flooding, was drawn as the main challenge in this work that could be mitigated by altering the composition of the preflush stage. For this production to be efficient in an unconventional formation, the results presented herein suggest a modification of the injection scheme..
18. Gen Murakami, Yuichi Sugai, Kyuro Sasaki, Preliminary study on in situ realtime quantitation of target bacteria on the principle of flow cytometry, 22nd International Biohydrometallurgy Symposium, 2017 22nd International Biohydrometallurgy Symposium, 10.4028/www.scientific.net/SSP.262.224, 262, 224-227, 2017.08, In-situ realtime method that can monitor the target bacteria should be used to determine the real situation of the bacteria in deep parts of heaps in heap bioleaching plants. This study suggest to apply flow cytometry technology to in-situ realtime monitoring of target bacteria. Flow cytometry is a method that can rapidly quantify the bacterial cells in bacterial suspension based on the detection of lights that are emitted from bacterial cells. In this study, we estimated the possibility of the application of flow cytometry to the selective detection of target bacteria. The bacterial culture solution that had been diluted by water including other bacteria was provided for fluorescence spectral analysis and scattered light analysis that were functions of flow cytometry. Our target bacteria could be selectively detected by those analyses in this study, therefore, it was shown that the flow cytometry could be useful for detecting target bacteria selectively. Because the measurement principle of flow cytometry is quite simple, it can be expected to be installed into deep heaps through the monitoring wells and determine the dominance of target bacteria in-situ and realtime in the future..
19. Yongjun Wang, Xiaoming Zhang, Yuichi Sugai, Kyuro Sasaki, Determination of Critical Self-Ignition Temperature of Low-Rank Coal Using a 1 m Wire-Mesh Basket and Extrapolation to Industrial Coal Piles, Energy & Fuels, 10.1021/acs.energyfuels.7b00409, 31, 7, 6700-6710, 2017.08, [URL], Testing of the self-heating and spontaneous combustion characteristics of large coal stockpiles is difficult owing to the influence and restrictions of various inconvenient factors, such as large space requirements, complicated measurement conditions, and the need for lengthy test periods. Heat generation from coal oxidation during storage is problematic, so researchers have sought methods of understanding the distribution and rise of internal temperatures in large low rank coal piles, with the aim of developing effective methods of predicting and controlling their spontaneous combustion. Several laboratory studies and numerical simulations have been carried out to predict and verify the self-heating and spontaneous combustion of coal piles. Wang et al. and Sasaki et al. presented preliminary experimental results using the Frank-Kamenetskii model to estimate the behavior of large coal piles by laboratory testing of the critical self-ignition temperature (CSIT) of small piles. Beamish et al. successfully achieved spontaneous combustion of coal by the systematic application of an anti-oxidant and tested the self-heating rates of a coal sample with a fixed particle size in the laboratory to develop an appropriate principal hazard management plan for law-rank coals. Fierro et al. developed a one-dimensional model to show that porosity and wind speed play an important role in coal pile oxidation, and verified their simulation results by application to stockpiles of mixed lignite..
20. Yousefi-Sahzabi Amin, Eda Unlu-Yucesoy, Kyuro Sasaki, Hossein Yuosefi, Arif Widiatmojo, Yuichi Sugai, Turkish Challenges for Low-Carbon Society: Current Status, Government Policies and Social Acceptance, Renewable and Sustainable Energy Reviews, 10.1016/j.rser.2016.09.090, 68, 1, 596-608, 2017.02, [URL], Turkey’s rapid economic growth followed by increasing gap between domestic energy production and consumption signifies the large-scale integration of low-carbon and renewable resources into energy system. Turkey’s energy demand is increasing and supplying fossil energies such as oil and gas is becoming more challenging due to the lack of domestic hydrocarbon resources. The country is facing two main issues; first, maintaining energy balance and second, handling environmental issues. Nevertheless, Turkey has substantial renewable and low-carbon energy resources with co-benefits for the country’s fast growing economy and environmental sustainability. This paper aims to present a comprehensive update on Turkey’s renewable and low-carbon energy sector. It reviews not only the current status of the technology, policy and economy, but also provides an insight into the social aspects as well. From a policy point of view, the paper critically discusses Turkey’s energy strategy and perspectives and from the social point of view, the paper argues that there is a research gap in recent literature regarding public awareness and social acceptance of low-carbon energy technologies. Also, the future challenges for promoting low-carbon society in Turkey are discussed in terms of sustainable development and socio-environmental conditions..
21. Olalekan S. Alade, Kyuro Sasaki, Yuichi Sugai, Bayonile Ademodi, Junpei Kumasaka, Effect of Emulsication Process Conditions on the Properties of Water-in-Bitumen Emulsion, 石油技術協会誌, 10.3720/japt.82.73, 82, 1, 73-84, 2017.01, [URL], SAGD法は、水蒸気生成と圧入に伴うエネルギーコスト、CO2排出量に関わる課題を有する。その解決策として界面活性剤水溶液を150℃程度で圧入し、水中油滴 (O/W) 型のエマルション化によって粘度を低下させ、ビチュメンを生産する生産スキームを提案する。ビチュメンおよびエマルションの粘度測定等に基づいて、提案した生産スキームに関する数値シミュレーションを実施し、従来のSAGD法との比較検討を行った。.
22. Yaguba Jalloh, Anuar Ahmad, Zulkarnaini Mat Amin, Kyuro Sasaki, Conventional Total Station Versus Digital Photogrammetry in Land Development Applications, Journal of Environmental & Analytical Toxicology, 10.4172/2161-0525.1000430, 7, 1, 430-1-430-2, 2017.01, In land development, the need for up to date planimetric plans is emphasised. Numerous techniques can be used to produce these plans such as traditional photogrammetry, satellite photogrammetry and terrestrial surveying using total station or Global Positioning System (GPS) techniques. However, for the purpose of this paper, GPS and total station are used together with photogrammetric techniques. GPS was used to establish ground control points for aerial triangulation in photogrammetry. Some selected portions within the campus of Universiti Teknologi Malaysia (UTM) are chosen to carry out this integration mapping [1]. Field surveying technique using total station is always adopted as a traditional method for planimetric plan production and mapping of urban and rural areas. Both the conventional surveying i.e., Total station and photogrammetry could be used for surveying purposes but the accuracy and techniques of each method differs from one another, hence in this project, both techniques are looked at in order to compare and draw some inferences. The main objectives will be to produce planimetric plan of the study area using conventional surveying technique (i.e., total station) and photogrammetric method to perform analysis of the two surveying methods..
23. Yaguba Jalloh, Anuar Ahmad, Zulkarnaini Mat Amin, Kyuro Sasaki, Conventional Total Station Versus Digital Photogrammetry in Land Development Applications, Journal of Environmental & Analytical Toxicology, 10.4172/2161-0525.1000430, 7, 1, 430-1-430-5, 2017.01, [URL], In land development, the need for up to date planimetric plans is emphasised. Numerous techniques can be used to produce these plans such as traditional photogrammetry, satellite photogrammetry and terrestrial surveying using total station or Global Positioning System (GPS) techniques. However, for the purpose of this paper, GPS and total station are used together with photogrammetric techniques. GPS was used to establish ground control points for aerial triangulation in photogrammetry. Some selected portions within the campus of Universiti Teknologi Malaysia (UTM) are chosen to carry out this integration mapping [1]. Field surveying technique using total station is always adopted as a traditional method for planimetric plan production and mapping of urban and rural areas. Both the conventional surveying i.e., Total station and photogrammetry could be used for surveying purposes but the accuracy and techniques of each method differs from one another, hence in this project, both techniques are looked at in order to compare and draw some inferences. The main objectives will be to produce planimetric plan of the study area using conventional surveying technique (i.e., total station) and photogrammetric method to perform analysis of the two surveying methods..
24. Olalekan S. Alade, Kyuro Sasaki, Bayonile Ademodi, Yuichi Sugai, Adeniyi S. Ogunlaja, Polyvinyl Alcohol (PVA) as an Emulsifying Agent for Viscosity Reduction of Heavy and Extra-Heavy Oils, Heavy Oil: Characteristics, Production and Emerging Technologies, 67-92, 2017.01.
25. Ronald Nguele, Kyuro Sasaki, Yuichi Sugai, Brian A. Omondi, Hikmat Said-Al Salim, Ryo Ueda, Interactions between Formation Rock and Petroleum Fluids during Microemulsion Flooding and Alteration of Heavy Oil Recovery Performance, Energy & Fuels, 10.1021/acs.energyfuels.6b02216, 31, 1, 255-270, 2017.01, [URL], In-situ emulsification/solubilization is an oil recovery technique routinely used to mobilize residual oil after the secondary oil production (waterflooding). The oil is produced after a subsequent reduction of interfacial tension (IFT) between stranded crude oil and water in the reservoir. Herein is presented a recovery method for heavy crude oils whose scheme consists of the injection of a fully solubilized (or emulsified) oil. Theoretically, the fully solubilized oil, referred hereinafter as microemulsion formulation, reduces the viscous forces that keep residual oil stranded. Different microemulsion formulations were prepared ex-situ from two heavy oils (API 11.5 and 16.6), micellar slugs from and low saline water. Tertiary heavy oil recovery consisted in displacing residual oil, from a water flooded core, by a specific microemulsion formulation followed by low-saline water, which acted as buffer solution. 31% of initial oil-in-place (IOIP) was recovered from water flooded core by microemulsion followed by an increment of about 20% of IOIP with chase water. The oil recovery efficiency by microemulsion and chase water flooding were lowered to 15% and 28% in a strong oil-wet core (i.e. non water flooded core). Despite the promising results presented herein, the performance of the microemulsion formulations, and thus the oil recovery efficiency, was found to be strongly dependent of (1) the nature of the core i.e. its mineralogy, (2) the state of plug i.e. wettability and (3) the chemical composition propagating fluid. The microemulsion formulations prompted a series of chemical reactions that subsequently altered their performance as displacing agent. Ion tracking analysis of the effluent fractions showed that the pH and the concentration in divalent and/or monovalent ions were altered also at each stage of production. When the plug was not water flooded, the oil was produced along with a deposit of sludge and a high emulsion cut. However, the use of preflush enriched with an alkali (Na2CO3), was found to dampen both effects. Furthermore, the spectral analysis revealed the formation of calcium bridges whose concentration reduced the efficiency of microemulsion formulations. Also, a series of chemical schemes, are proposed in this investigation, to support these results. Lastly, this investigation proposes a simplified electrostatic model that explains further the formations of clusters, which were promoted by propagation of displacing fluids..
26. Yaguba Jalloh, Kyuro Sasaki, Mustapha Olajiday Thomas, The Influence of Local Geology on the Groundwater Potential of Kunike, Hydrol Current Research, 10.4172/2157-7587.1000262, 7, 4, 262-1-262-6, 2016.12, This research investigated the influence of the local geology on the groundwater potential of the two kunike chiefdoms (Sanda and Barina) in the Tonkolili District, Northern Sierra Leone. The local geology is made up of rocks typical of the West African Archean greenstone belt. The stratigraphic sequence is marked by the basic ultramafics followed by mafics (metavolcanics) and a metasedimentary unit i.e., quartzite and banded iron formations in a greenstone belt lying on or beside granitic basement rocks. The basement relationship of the granites to the supracrustals has been obliterated by intrusion of Late-Kinematic granites and by deformation and metamorphism during the Liberian tectonothermal event (=2700 Ma) which produced the dominant N-S to NNE-SSW trend. Because of the geology, aquifers in the studied area are located in two different lithologies-granitic terrain and schist belt. Aquifer characteristics such as transmissivity and yield were measured and compared for the different lithologies. Comparison results show that the yield is greater (0.03%) in the granitic terrain than in the schist belt. And this is because of the presence of clays in the schist belt. The research also revealed that groundwater is readily available in the area..
27. Ibrahim Al Hadabi, Kyuro Sasaki, Yuichi Sugai, The Effect of Kaolinite on Water-In-Oil Emulsion Formed by Steam Injection during Tertiary Oil Recovery: A Case Study of an Omani Heavy Oil Sandstone Reservoir with a High Kaolinite Sludge Content, Energy & Fuels, 10.1021/acs.energyfuels.6b01822, 30, 12, 10917-10924, 2016.12, [URL], In this research, a numerical feasibility study of the thermal oil recovery using steam injection has been carried out for a heterogeneous heavy oil field located in southern Oman..
28. Ibrahim Al Hadabi, Kyuro Sasaki, Yuichi Sugai, Yousefi-Sahzabi, A., Steam Trap Control Valve for Enhancing Steam Flood Performance in an Omani Heterogeneous Heavy Oil Field, Journal of Unconventional Oil and Gas Resources, 10.1016/j.juogr.2016.03.005, 16, 113-121, 2016.12, [URL], In this research, a numerical feasibility study of the thermal oil recovery using steam injection has been carried out for a heterogeneous heavy oil field located in southern Oman..
29. Olalekan S. Alade, Kyuro Sasaki, Adeniyi Sunday Ogunlaja, Yuichi Sugai, Bayonile Ademodi, Junpei Kumasaka, Thermal Tolerance and Compatibility of NaOH-Poly (Vinyl Alcohol) in Bitumen Emulsification for Improved Flow Properties, Energy & Fuels, 10.1021/acs.energyfuels.6b02060, 30, 11, 9310-9321, 2016.09, [URL], The batch emulsification experiments were performed to investigate the thermal degradation tolerance and compatibility with ethanol-NaOH solution. Bitumen was emulsify using the heated samples of PVA..
30. Ferian Anggara, Kyuro Sasaki, Yuichi Sugai, The Correlation between Coal Swelling and Permeability during CO2 Sequestration: A Case Study using Kushiro Low Rank Coals, International Journal of Coal Geology, 10.1016/j.coal.2016.08.020, 2016.08, [URL], This study investigates the relationship between Kushiro lignite-subbituminous coal matrix swelling and gas permeability during CO2 sequestration. Banded and non-banded coal samples have been used in swelling experiments. Banded coal samples tend to have anisotropic swelling, whereas non-banded samples tend to have isotropic swelling..
31. Ronald Nguele, Kyuro Sasaki, Mohammad Reza Ghulami, Yuichi Sugai, Masanori Nakano, Pseudo-phase Equilibrium of Light and Heavy Crude oils for Enhanced Oil Recovery, Journal of Petroleum Exploration and Production Technology, 10.1007/s13202-015-0195-5, 6, 3, 419-432, 2016.09, [URL], Presented paper, herein, is on phase equilibrium of light and heavy crudes known to be closely related to enhanced oil recovery (EOR). In miscible gas injection, the advancing gas (or injecting fluid) develops with petroleum fluids a miscibility front in the reservoir fluids that further reduces the viscous forces holding crudes stranded. The present work presents a phase equilibrium scheme upon which heavy oil swelling and light crude vaporization were found when carbon dioxide (or methane) was used as advancing gas. Heavy crude swelling was observed to be not only dependent on gas solubility but also on the chemical composition of the crude oil. Although a small fraction of injecting gas was distributed in the reservoir water, the initial water–oil ratio was seen to alter the bubble-point pressure from 10 to 30 % depending of the injected gas. In order to mimic miscible-like behavior during gas injection, a dynamic description of methane and carbon dioxide was proposed. Alteration of PVT parameters below and beyond the bubble-point pressure was highlighted therefrom..
32. Abu Bakarr Jalloh, Kyuro Sasaki, Yaguba Jalloh, Abubakarr Karim Barrie, Integrating Artificial Neural Networks and Geostatistics for Optimum 3D Geological Block Modeling in Mineral Reserve Estimation: A Case Study, International Journal of Mining Science and Technology, 10.1016/j.ijmst.2016.0, 26, 4, 581-585, 2016.07, [URL], In this research, a method called Artificial Neural Network Model integrated with Geostatiscs(ANNMG) is presented to integrate Artificial Neural Networks and Geostatistics for optimum mineral reserve evaluation..
33. Olalekan S. Alade, Bayonile Ademodi, Kyuro Sasaki, Yuichi Sugai, Junpei Kumasaka, Adeniyi Sunday Ogunlaja, Development of Models to Predict The Viscosity of A Compressed Nigerian Bitumen and Theological Property of Its Emulsions, Journal of Petroleum Science and Engineering, 10.1016/j.petrol.2016.06.040, 138, 2016.06, [URL], In the present study, bitumen was dispersed in the aqueous solution of PVA (Poly Vinyl Alcohol) containing dissolved salt (NaCl). The stability and rheological property were studied to evaluate the characteristics of the dispersion system under the influence of salt. Under an isothermal condition (temperature of 20 °C), it was observed that the stability of bitumen-in-water emulsion containing 50% bitumen content, was increased by the dissolution of 0.5% w/w salt in the aqueous phase while at the salt content of 1% w/w and above, the stability of emulsion was decreased. In addition, the tolerance of the chemical to salinity was confirmed since the surface tension of the aqueous solution and the particle size of emulsions were not significantly affected at the level of salinity considered in this study. Moreover, analysis of the rheological property indicated that, the emulsions behave as non-Newtonian pseudoplastic (shear thinning) fluid regardless of the salt content. The apparent viscosity of emulsion was not significantly affected at up to salinity level of 1.0% w/w; while the salt content of 2% w/w and 3.5% w/w increased the apparent viscosity of emulsion..
34. Hiroki Matsuda, Takafumi Yamakawa, Yuichi Sugai, Kyuro Sasaki, Gas Production from Offshore Methane Hydrate Layer and Seabed Subsidence by Depressurization Method, Engineering, 10.4236/eng.2016.86033, 8, 6, 353-364, 2016.06, [URL], Numerical simulations on consolidation effects have been carried out for gas production from offshore methane hydrates (MH) layers and subsidence at seafloor..
35. Very Susanto, Kyuro Sasaki, Yuichi Sugai, Wataru Kawasaki, Field Test Study on Leakage Monitoring at A Geological CO2 Storage Site using Hydrogen as A Tracer, International Journal of Greenhouse Gas Control, 10.1016/j.ijggc.2016.04.001, 40, July, 37-48, 2016.04, [URL], In this study, a new monitoring approach for detecting CO2 leakage is proposed that utilizes hydrogen gas as a tracer for CO2 geological storage..
36. Junpei Kumasaka, Kyuro Sasaki, Yuichi Sugai, Olalekan S. Alade, Masanori Nakano, Measurement of Viscosity Alteration for Emulsion and Numerical Simulation on Bitumen Production by SAGD Considering In-situ Emulsification, Journal of Earth Science and Engineering, 6, 1, 10-17, 2016.03, [URL], A thermal steam stimulation process, such as steam-assisted gravity drainage (SAGD), induces water-in-oil emulsion of heavy oil or bitumen throughout the production..
37. Chanmoly Or, Kyuro Sasaki, Yuichi Sugai, Masanori Nakano, Motonao Imai, Swelling and Viscosity Reduction of Heavy Oil by CO2-Gas Foaming in Immiscible Condition, SPE Reservoir Evaluation & Engineering, 10.2118/179738-PA, 19, 1, 1-12, 2016.03, [URL], In this study, foaming of heavy oil generated by depressurization from saturated carbon dioxide (CO2) solution was studied because generating foamy oil has a possibility of developing an enhanced oil recovery (EOR). The experiments were carried out by with a heavy crude oil at CO2 pressure less than 10 MPa and temperature from 20 to 50°C. The swellings of the generated foamy oils increased from 36.8 to 47.5% with reducing viscosity ratio from 79 to 42%, comparing with original viscosity. Furthermore, the investigation shows that CO2 microbubbles in the foamy oil started nucleating at pressure less than 8.0 MPa during depressurizationfrom the saturation pressure of 9.97 MPa at 50°C, and the foamy oil started decreasing the apparent viscosity. By exposing generated foamy oil under the shear rate of 76.8 seconds-1 for 5 minutes, the bubble-volume density profile changes from broadband toward to Gaussian distribution caused by disappearing larger size of gas bubbles, where bubble diameter of the maximum probability density of the bubble-volume distribution reduced from 80 µm to less than 10 µm. However, reduction of viscosity ratio was almost kept even though the distribution was changed; this shows that apparent viscosity strongly depends on the microbubbles sized less than 10 µm in diameter. It was expected that CO2 foamy oil has a potential to improve the recovery ratio of heavy oil by making the residual oil flow out from the immobile zones because of its large apparent swelling and improving mobility in porous oil-flow..
38. Chanmoly Or, Kyuro Sasaki, Yuichi Sugai, Masanori Nakano, Motonao Imai, Preliminary Numerical Modelling of CO2 Gas Foaming in Heavy Oil and Simulations of Oil Production from Heavy Oil Reservoirs, The Canadian Journal of Chemical Engineering, 10.1002/cjce.22416, 94, 3, 576-585, 2016.03, [URL], Basic understanding of numerical modelling for the effects of CO2 foaming on heavy oil production behaviour using the huff-and-puff process is relevant for CO2-EOR performance. The numerical model was constructed based on laboratory measurements: CO2 solubility, foam swelling, and apparent viscosity. The model for unsaturated solubility in porous media, such as sandstone cores and oil reservoirs, was proposed by defining CO2 solubility in heavy oil for generating foamy oil. The foaming process was modelled with four kinds of foamy oils at discrete depressurizations below each equilibrium pressure. A numerical model of apparent foam viscosity with discrete depressurization was set up based on experimental measurements as a function of pressure and temperature of 0.1–10 MPa and 20–50 °C. The matching between the numerical simulations of heavy oil drainage and experimental measurements of foaming in Berea sandstone cores (Psat = 10 MPa at 50 °C) shows 31% oil recovery after depressurization to atmospheric pressure. The numerical simulation results of heavy oil production at field-scale showed that CO2 gas production quickly increases after depressurization and then the foamy oil production increases following the peak gas production rate. In the first cycle of the huff-and-puff process, the maximum oil production rate ranged of 4–68 m3/day. From the sensitivity study it can be concluded that the initial oil saturation and the CO2 dissolution zone as compared with reservoir size play a main function in heavy oil production by CO2 gas foaming in the huff-and-puff process..
39. Olalekan S. Alade, Kyuro Sasaki, Yuichi Sugai, Bayonile Ademodi, Masanori Nakano, Bitumen Emulsification using A Hydrophilic Polymeric Surfactant: Performance Evaluation in The Presence of Salinity, Journal of Petroleum Science and Engineering, 10.1016/j.petrol.2015.11.031, 138, Feb, 66-76, 2016.02, [URL], In the present study, bitumen was dispersed in the aqueous solution of PVA (Poly Vinyl Alcohol) containing dissolved salt (NaCl). The stability and rheological property were studied to evaluate the characteristics of the dispersion system under the influence of salt. Under an isothermal condition (temperature of 20 °C), it was observed that the stability of bitumen-in-water emulsion containing 50% bitumen content, was increased by the dissolution of 0.5% w/w salt in the aqueous phase while at the salt content of 1% w/w and above, the stability of emulsion was decreased. In addition, the tolerance of the chemical to salinity was confirmed since the surface tension of the aqueous solution and the particle size of emulsions were not significantly affected at the level of salinity considered in this study. Moreover, analysis of the rheological property indicated that, the emulsions behave as non-Newtonian pseudoplastic (shear thinning) fluid regardless of the salt content. The apparent viscosity of emulsion was not significantly affected at up to salinity level of 1.0% w/w; while the salt content of 2% w/w and 3.5% w/w increased the apparent viscosity of emulsion..
40. Ronald Nguele, Kyuro Sasaki, Hikmat Said-Al Salim, Yuichi Sugai, Experimental Analysis of Surface Tension Alteration by Salinity Change for Oil-Wet Rocks, International Journal of Earth Sciences and Engineering, 9, 1, 29-31, 2016.02, Wettability of porous media is altered from preferential liquid-wetting to preferential gas-wetting. The present work is an insight that addresses the issue of wettability alteration by change in brine. Moreover, herein is presented the effect of reservoir water concentration on surface tension of oil. By means of contact angle measurements, a Berea sandstone core was saturated with crude oil and used as reservoir rock. Not only the spreading was found to be dependent of the contacting fluid properties, but also the surface tension increased significantly with the concentration in brine. Moreover, the spreading on the core, which to an extent accesses the performance of waterflooding, was seen to be altered by chemical composition of the brine..
41. Mohammad Reza Ghulami, Kyuro Sasaki, Ronald Nguele, Yuichi Sugai, Experimental Study and Numerical Simulation of Methane Solubility in Crude Oil for Gas Injection Enhanced Oil Recovery, International Journal of Earth Sciences and Engineering, 9, 1, 37-40, 2016.02, Gas injection enhanced oil recovery has long been used in petroleum industry to increase oil recovery factor. Carbon dioxide, nitrogen, flue gas and lean hydrocarbon gases were all being utilized as displacing agents. The oil swelling is an indicator of amount of gas dissolved into oil phase. Swelled oil has lower viscosity and flows more easily, then it improves recovery factor. In current study, a crude oil sample was used for experimental investigation. Solubility of methane gas in oil and swelling factor of the oil were measured by a Pressure-Volume-Temperature apparatus and High-Pressure-Cell equipment, respectively. Furthermore, reservoir simulation software, CMG-WINPROP, was used to estimate the PVT properties of gas-oil mixture and compare it with experimental data. It was used to calculate gas solubility and oil swelling factor, and also tune the equation of state with experimental data. Experimental result shows that the solubility of methane in oil phase and swelling factor of oil increase proportionally with pressure. Moreover, reservoir fluid phase behavior was predicted using a tuned equation of state against experimental data..
42. Ibrahim Al Hadabi, Kyuro Sasaki, Yuichi Sugai, Effects of Kaolinite Clay on Omani Heavy-Oil Rheology in Considering Enhanced Oil Recovery by Steam Injection, International Journal of Earth Sciences and Engineering, 9, 1, 22-24, 2016.02, The presence of clays in the reservoir plays an important role in EOR applications. The focus of this paper is to characterize the heavy oil rheology behaviour with the presence of kaolinite clay mineral in considering an EOR process using steam injection. The effect of the kaolinite clay concentration has been investigated for viscosity changes in heavy oil and its water-in-oil emulsion formed after steam injection. The clay mineral used in this study is powder kaolinite clay for the Omani heavy-crude oil with 21 ºAPI at 23 ºC. A viscosity was measured to understand the rheology changes by including kaolinite in the original heavy oil and its water-in-oil emulsion formed after steam injection. The experimental results showed that presence of kaolinite clay in the heavy oil results in reducing the viscosity of heavy crude oil and its emulsion at high share rate..
43. Abu Bakarr Jalloh, Kyuro Sasaki, Drillhole Modelling using Geological Characteristics and Conditional Simulation for Mining Feasibility Studies - Case Study on an Iron Ore Mine in Sierra Leone, International Journal of Earth Sciences and Engineering, 9, 1, 15-21, 2016.02, The unpredictable fluctuations in metal price, political instability and socio-economic problems in resource rich areas are among the reasons why the mining industry needs to look for ways of maximizing returns whilst keeping operating costs at their lowest. In this research, the potential of improving exploration programs was investigated using a drillhole data modelling scheme based on the geology of the deposit. Secondly, the application of Geostatistical Simulation for mine design was investigated. A dataset consisting of 539 drillholes was used as a case study with grid dimensions of x (3100 m) by y (3800 m). Using the drillhole modelling scheme, the drillholes were segmented into groups using geological features based on which five (5) possible geological patterns were constructed. Each geological pattern was simulated 1000 times to capture the space of uncertainty, and the simulated realizations for each of the pattern were averaged to produce one block model per pattern. This modelling scheme showed how the geological information can be used optimally to reduce drilling requirement during mining feasibility studies. From analysis, it was concluded that the project could save the drilling and sample analysis cost combined by a margin of 32% using this method..
44. Ronald Nguele, Kyuro Sasaki, Hikmat Said-Al Salim, Yuichi Sugai, Arif Widiatmojo, Masanori Nakano, Microemulsion and Phase Behavior Properties of (Dimeric Ammonium Surfactant Salt – Heavy Crude Oil – Connate Water) System, Journal of Unconventional Oil and Gas Resources, 10.1016/j.juogr.2016.03.001, 14, June, 62-71, 2016.01, Fundamentally, recovery methods of untapped crude oils require injection of foreign material(s) in the reservoir, which subsequently promote(s) the displacement of residual oil. In chemical enhanced oil recovery (EOR), the microscopic sweep efficiency depends primarily on achievement of a low interfacial tension. The present work investigates into the surface tension and phase behavior properties of microemulsion developed from a contact between a dimeric ammonium salt surfactant achieve an ultra-low interfacial tension (IFT) was compared with a conventional polysorbate surfactant commonly used in chemical EOR. At fairly low concentration, dimeric surfactants achieved an IFT of order of 103 mN/m. Salinity tolerance and IFT were significantly altered not only by the heaviness i.e. API of the crude, but also by the reservoir conditions. Moreover, alkane carbon number (ACN), introduced in this work, revealed that modeling a micellar slug formulation solely based on chemical composition of the crude and/or its nature could be misleading. Presence of divalent ions was found to promote the increase in IFT rather to a shift to a lower value. Also, a relative low adsorption of micellar slug was found in both dolomite and Berea sandstone. However, active head of the dimeric surfactant showed a preferential attachment to carbonate rock while low interactions were observed for sandstone. Lastly, the present study has highlighted an inhibiting acidity activity for dimeric ammoniums salt surfactants..
45. Ronald Nguele, Mohammad Reza Ghulami, Kyuro Sasaki, Hikmat Said-Al Salim, Arif Widiatmojo, Yuichi Sugai, Masanori Nakano, Asphaltene Aggregation in Crude Oils during Supercritical Gas Injection, Energy & Fuels, 10.1021/acs.energyfuels.5b02903, 30, 2, 1266-1278, 2016.01, [URL], This paper presents aggregation of asphaltenic materials in three dead crude oils including two heavy samples from Hokkaido (Japan) and an extra heavy sample from Canada. In here, a modified ASTM D3279 method and PVT test were used to estimate the amount of precipitated asphaltene and the experimental bubble-point pressures of the samples. Upon which, a crude oil characterization was performed following pseudo-component approach with the use of molecular weight and specific gravity of single carbon number from oil assay data as distribution variables. A simplified thermodynamic model, derived from the solubility model, was used to correlate the maximum asphaltene soluble with the aggregated amount. This study has highlighted that the oil precipitation, during its titration, occurs as a function of both the molecular weight of the titrant and the carbon-to-hydrogen ratio in the asphaltene phase. Furthermore, the kinetics and the stability of intermolecular forces, developed during the miscibility process, are believed to alter oil polarity and gas solubility. More specifically, pressurization of the system [oil - supercritical gas] decreases concurrently the solubility parameters of the asphaltene fraction and increases the solvating strength of gas. Herein was also demonstrated that asphaltenes are less soluble in impure gases compared to the pure one. At/near the bubble-point pressure, the supercritical gas, in contact with the oil, develops a potential as either a flocculent or coagulant. The increase in pseudo equilibrium temperature attained after gas injection was found also to alter asphaltene aggregation..
46. Arif Widiatomojo, Kyuro Sasaki, Nuhindro Priagung Widodo, Yuichi Sugai, Amin Yousefi-sahzabi, Ronald Nguele, Predicting Gas Dispersion in Large Scale Underground Ventilation: A Particle Tracking Approach, Building and Environment, 10.1016/j.buildenv.2015.07.025, 95, 171-181, 2016.01, [URL], The present work highlights the gas dispersion evaluation in large underground tunnel ventilation by means of tracer gas measurement and numerical simulation using particle tracking method. Ventilation system is a tool to control pollutants and/or hazardous gas spreading. The use of grid-based numerical method is limited by the spatial dimension of ventilation network. Therefore, the applicability of such technique for large ventilation network is constrained. A Lagrangian based Particle Tracking method is proposed to evaluate the dispersion of tracer gas from a releasing point to the downstream position in a complex ventilation system. This method simulates mass transport by discretizing mass concentration into numbers of particles. Rather to solving the transport equation in grid system to obtain the mass concentration, this technique simulates mass concentration by counting number of particles at any specified position within the ventilation network. In this research, the network splitting scheme was used to simulate particles' transition in junctions. Further, it was found that by setting effective diffusion coefficient to 47 times larger than those for common underground airway and with velocity correction factor of a ¼ 0.59, a good agreement between particle tracking result and tracer gas measurement data can be achieved. This results suggests that the analytical approach in evaluating gas (or pollutant) dispersion and residence time in large ventilation system by the means of conventional ventilation network analysis have to consider both mechanical dispersion and the effect of delay due to trapping mechanism of gas..
47. Ronald Nguele, Kyuro Sasaki, Hikmat Said-Al Salim, Yuichi Sugai, Physicochemical and Microemulsion Properties of Oimeric Quaternary Ammonium Salts With Trimethylene Spacer for Enhanced Oil Recovery, Colloid and Polymer Science, 10.1007/s00396-015-3701-x, 293, 12, 3487-3497, 2015.12, Dimeric surfactants, also termed as Gemini surfactants, are regarded as organic materials which have two hydrophilic head groups and two hydrophobic groups in the molecules linked together with a spacer. In this study, dimeric surfactants of quaternary ammonium bromide connected with a trimethylene spacer group (m-3-m) have been investigated as potential micellar solutions for enhanced oil recovery. Static surface tension, interfacial tension as well as optimal salinity characterized their physicochemical and microemulsion properties. Using modeled petroleum fluids, the critical micelle concentration (CMC) was found dependent not only of the chemical architecture of the surfactant but also of the composition in the liquid phase. The nature and/or the length of spacer group participates significantly to the spatial rearrangement of the dimeric surfactants which subsequently altered the surface properties. For the same spacer group, an ultralow interfacial tension was achieved. Encouraging oil solubilization was found for surfactants used with an effect pronounced for longer alkyl chain. Furthermore, both the effects and the presence of metallic divalent ions on the phase behavior were discussed..
48. Paike Htwe, Sugeng Sapto Surjono, Donatus Hendra Amijaya, Kyuro Sasaki, Depositional Model Of Ngrayong Formation In Madura Area, North East Java Basin, Indonesia, Journal of Applied Geology, 7, 2, 49-58, 2015.12, [URL], The early Middle Miocene Ngrayong Formation, an important reservoir of North East Java Basin, is well exposed in the central anticlinal part of Madura Island. The purpose of current study is to classify the epositional environments of the study area based on the characteristics and geometry of sedimentary facies. In the Madura island, the thicker clastics and deeper carbonates of Ngimbang Formation and Kujung Formation of Late Oligocene-Early Miocene deposited in the northeast-southwest asymmetrical half grabens. After the deposition of Kujung Formation, the basin morphology developed nearly eastwest trending shelf edge and the deposition of Tuban Formation began. The fine grained complex of Tuban Formation was followed by the Ngrayong Sandstones deposition. The depositional model of Ngrayong Formation is being producing of wide variety of depositional environments. Large scale cross-bedded sandstones and bioturbated massive sandstones with thin to medium bedded argillaceous limestone that outcrop in the northern part of the study area are deposited in costal environment. The heterolithic sandstone with planar and trough cross-lamination, fine grained sandstone with interlaminated structure and bioclastic carbonate exposed in the central part of the study area are deposited in upper shallow marine area. Dark grey siltstones and mudstones deposited in lower shallow marine area are well exposed in southern part of the study area. In conclusion, Ngrayong Formation in Madura area is developed in three depositional units which are coastal, upper shallow marine and lower shallow marine..
49. , [URL].
50. Yuichi Sugai, Very Susanto, Kyuro Sasaki, Ryo Mori, Spectrophotometric Determination of pH Change of Formation Water Under High CO2 Pressure Using a Mixed pH Indicator, Journal of MMIJ, 10.2473/journalofmmij.131.518, 131, 8,9, 518-523, 2015.08.
51. Ferian Anggara, Kyuro Sasaki, Yuichi Sugai, Numerical Modelling and Simulation of CO2–Enhanced Coal-bed Methane Recovery (CO2-ECBMR): The Effect of Coal Swelling on Gas Production Performance, Journal of Applied Geology, 7, 2, 102-111, 2015.12, [URL], This presents study investigate the effect of swelling on gas production performances at coal reservoirs during CO2-ECBMR processes..
52. Arif Widiatomojo, Kyuro Sasaki, Amin Yousefi-sahzabi, Ronald Nguele, Yuichi Sugai, Atsushi Maeda, A Grid-free Particle Tracking Simulation for Tracer Dispersion in Porous Reservoir Model, Journal of Unconventional Oil and Gas Resources, 10.1016/j.juogr.2015.05.005, 11, September, 76-81, 2015.09, [URL], Tracer test is a useful method to investigate various phenomena in geological porous media including groundwater contaminant transport, sweep efficiency and retention time in oil reservoir, reservoir characterization, fractures orientation assessment, as well as geothermal reservoir evaluation. Numerical methods are powerful tools in interpreting tracer test results. However, they are limited by computational restrictions which include finer grid requirements and small calculation steps. In this study, an analog model of a quarter five-spot porous reservoir was simulated by using random walk particle tracking method. This scheme used ‘method of images’ with pairs of injector–producer potential flow to generate the velocity vectors instead of conventionally solving Darcy’s equation to obtain grid velocities. Simulated breakthrough concentration profiles and flow visualization were compared with both experimental results and Eulerian-grid based finite volume simulation. The predicted breakthrough curves of tracer concentration were found to agree with experimental data sets. In addition to be free from numerical errors as often encountered in grid-based simulation, the proposed particle tracking model showed a faster computational time. Unlike the conventional grid method, this technique provides inherently smooth and continuous flow field at arbitrary position within the reservoir model..
53. Olalekan S. Alade, Kyuro Sasaki, Yuichi Sugai, Bayonile Ademodi, Junpei Kumasaka, Masanori Nakano, Prospects of Bitumen Emulsification using a Hydrophilic Polymeric Surfactant, International Journal of Engineering Practical Research, 4, 1, 55-59, 2015.04, [URL], One of the most important factors of the successful production, transportation and utilization of the highly viscous oil such as bitumen is viscosity reduction. Several approaches including emulsification of bitumen as dispersed particle in the continuous aqueous phase containing surfactant have been investigated and practised. However, recent progress in heavy oil emulsification has witnessed the use of polymeric surfactants. The use of this type of surfactants have been supported by observations including the ability to form emulsion which is easy to brake and environmental friendly compared to the low molecular weight surfactants. The present effort therefore seeks primarily to investigate the suitability of a hydrophilic polymeric surfactant in viscosity reduction of the bitumen. It has been observed that the sample of polymeric surfactant employed is able to significantly reduce the viscosity of the original sample of bitumen and stabilized the emulsion formed..
54. Ronald Nguele, Kyuro Sasaki, Yuichi Sugai, Hikmat Said-Al Salim, Mohammad Reza Ghulami, Masanori Nakano, Experimental Investigation of Brine Hardness and Its Induced Chemistry during Heavy Crude Recovery through CO2 Injection, International Journal of Engineering Practical Research, 4, 1, 60-66, 2015.04, [URL], In a typical oil reservoir, untapped crude co‐exists with water (connate water or brine) whose chemical composition depends on the formation in which it trapped. Although CO2‐EOR has been lately regarded as viable recovery technique for heavy crudes, its applicability on the field scale lies in understandings of various phenomena among which induced chemistry. In this research, we proposed to evaluate the extent to which brine salinity and hardness as well as an induced chemistry inherent to CO2 injection alter heavy oil recovery. Conducted at a laboratory scale, CO2was selected as a displacing agent to be injected in an analysis cell of a PVT apparatus within which reservoir physical conditions were reproduced. A heavy crude (API 11.5o) and three brine solutions chemically different were selected as displaced fluids. CO2 showed a high solubility, which increased with the pressure, comparatively to methane in both pure component hexadecane and heavy crude with a bubble point –pressure at 7.8 MPa. Salinity, taken alone, was found not to alter gas solubility, however the build‐up in Ca2+ and Mg2+ within connate water impacted invariably GOR..
55. Ronald Nguele, Hikmat Said Al-Salim, Kyuro Sasaki, Oil Condition Monitoring-Degradation Mechanisms and Additive Depletion, Journal of Multidisciplinary Engineering Science and Technology , http://www.jmest.org/wp-content/uploads/JMESTN42350515.pdf, 2, 3, 355-360, 2015.03, Primarily designed to provide hydrodynamic friction between mechanical parts of a mechanical engine, lubricating oils are hydrocarbon mixtures composed of base oils and chemical enhancers or additives. The degradation of a lubricant should be regarded as a result of depletion in its additives. Through an extensive analysis of various grades of car engine oils, this work intended to elucidate the chemical mechanisms responsible of depletion in additives , thus loss of efficiency. Using both analytical tools and traditional oil condition monitoring techniques, performance enhancers degradation was found to be induced by a complex tribo-chemistry process occurring within the engine. Furthermore, physical conditions existing within were believed to promote oxidation processes that yielded acidic materials causing lubricant performance alteration. Triggered by wear metals, it has been established that conversion of antioxidant additives along with inhibition of antiwears were primary reasons of loss of efficiency. This study has not only highlighted the catalytic and inhibiting strength of wear metals, but also it has discussed, on a chemical point of view, mechanisms leading to additive depletions..
56. Yongjun Wang, Xiaoming Zhang, Yuichi Sugai, Kyuro Sasaki, A study on Preventing Spontaneous Combustion of Residual coal in A coal Mine Goaf, Journal of Geological Research, 2015, 712349, 1-8, 2015.03, In this study, the effectiveness of grouting scheme has been simulated to prevent the coal spontaneous combustion at a goaf in Haizi Colliery, China. The colliery has been operated for long period over 27 years and has a complex ventilation network including airflow leakages which could possibly lead to the spontaneous combustion of coal at goafs. Firstly, the mine ventilat ion simulator MIVENA was used to analyze the mine ventilation network airflows to control airflows in and out of working faces and goafs. As the second pproach, numerical simulations were carried by the simulator FLUENT in order to predict spontaneous combustion of residual coal with leakage flow in the #3205 goaf. It was cleared that the goaf can be divided into three zones based on Oxygen concentration in the goaf area. Finally, the numerical simulat ion results show that the slurry grouting method is able to be as an effective and economical method by reducing porosity in the goaf area to prevent spontaneous combustion of residual coal..
57. , [URL].
58. Kyuro Sasaki, Yuichi Sugai, Chanmoly Or, Yuta Yoshioka, Junpei Kumasaka, Masanori Nakano, Motonao Imai(2014) : Fluids Behaviors in Heavy Oil Production - Water-in-Oil Emulsion, CO2-Gas Foam and In-Situ Combustion, Journal of the Japanese Association for Petroleum Technology, 79-6, 391-397 (in Japanese)., [URL].
59. Chanmoly Or, Kyuro Sasaki, Yuichi Sugai, Masanori Nakano, Motonao Imai, Numerical simulation of CO2 gas microbubble of foamy oil, Energy Procedia (Elsevier), doi:10.1016/j.egypro.2014.11.816, 63, 7821-7829, 2014.12, Heavy oil production by CO2 gas foaming has been simulated with a function of depressurization pressure. The numerical simulation was carried out by using CMG-STARSTM and based on experimental physical properties of foamy oil such as foam swelling and apparent viscosity. The matching between the numerical simulations of heavy oil drainage and experimental measurements of foaming in Berea sandstone cores (Psat = 10 MPa at 50 °C) shows 31% of oil recovery after depressurization to atmospheric pressure. The behavior of heavy oil production and production scheme were proposed with assuming the CO2 gas dissolution zone. The effect of initial oil saturation and CO2 dissolution zone are the controlling factors of heavy oil production..
60. Amin Yousefi-Sahzabi, Kyuro Sasaki, Debra J. Davidson, Akiya Nagata, Hossein Yousefi, Climate Technology Investment and Innovation: Potential Benefits of CO2 Capture from The Air, Investment Management and Financial Innovations, 11, 4, 292-303, 2014.12, [URL], The purpose of this paper is to provide insights into technological innovation and investment for CO2 reduction with focusing on the concepts of carbon capture and storage (CCS) and CO2 direct air capture (DAC) technology. The paper initially argues the necessities and motivations for technology innovation as an effective approach for addressing climate change problem. Then, it undertakes investigations to track the main features, technical progresses, and potential benefits of CO2 air capture over conventional methods. Finally, economical aspects and cost feasibility issues associated with this technology are discussed. The study approves air capture as an effective and feasible investment for climate change mitigation, subject to extensive commitments and strong policy supports..
61. Amin Yousefi-Sahzabi, Kyuro Sasaki, Hossein Yousefi, Some Thoughts on The Notion of Environmental Infomation Science, Electronic Green Journal, 1, 37, 1-16, 2014.12, [URL].
62. Haruhiro Suzuki, Yousefi-Sahzabi, A., Yuichi Sugai, Hossein Yousefi, Kyuro Sasaki, Economical Considerations on CCS System for Geological Uncertainty and Injection Failure, International Journal of Energy Economics and Policy, 4, 4, 772-784, 2014.11, [URL], In this study, an operation research on the performances of Tomakomai CCS project has been carried out for investigating the permeability uncertainty and the failures on CO2 operation and transportation. Firstly, economical effects of estimation error in aquifer permeability were investigated by using a reservoir block modeling based on numerical simulation results on CO2 injection rate. Secondary, economic loss resulted from failure of CO2 injection was evaluated by assuming periodical injection halts. It is clear that CO2 buffers, such as sphere gas tanks, should be installed to store CO2 on the CCS process which can temporarily store CO2 after it is captured when a trouble on transportation or injection processes occurs. Without a buffer, releasing the captured CO2 to the atmosphere due to system failure or trouble in injection will add to capture costs, or will result in carbon tax or opportunity loss on CCS. The larger size of CO2 buffer volume can potentially withstand against long-term trouble, however the larger buffer volume needs larger cost for initial construction and maintenance. The study also present the optimum CO2 buffer volume based on economical evaluations for a commercial CCS model based on several simulations performed with and without CO2 buffer in the system..
63. Arif Widiatmojo, Kyuro Sasaki, Masanori Matsumura, Yuichi Sugai, Laboratory Experiment of Air Eesidence Time in A Side Rectangular Cavity, Advanced Chemical Engineering Research, 3, 1, 27-33, 2014.06, Dispersion phenomena in underground mine ventilation system is an important parameter in controlling the spreading of gas or other particulate matter throughout the mine. From the results of tracer gas measurement in underground mine ventilation, it was found that the evaluated dispersion coefficient is larger than theoretical value. The presence of cavities and dead ends in along mine ventilation airways are supposed to be the main cause of this finding. The trapped gas inside cavity also harmful for workers, therefore adequate ventilation should be provided to dilute. In present study, the air residence time in a cavity was investigated by using tracer gas released in cavity and the decay time was measured required for the gas to completely escaped. The air exchange rates and the cavity’s ventilation efficiency were investigated in correlation with cavity’s aspect ratio and free stream velocity..
64. Kyuro Sasaki, Yuichi Sugai, Shinji Ono, Gas-to-wire System for Gas Production from Methane Hydrates Reserves, 21st World Petroleum Congress 2014 (WPC2014), 3, 2191-2202, 2014.06, [URL], Huge Methane Hydrates (HM) reserves are expected to be unconventional natural gas resources reserved at Arctic area. However their developments are economically difficult, because dissociation heat is limited and gas transportation is costly in the area. In this study, the “Gas-To-Wire” system has been proposed to provide economical gas production system from MH layers. The system is an integrated gas production system that generates electricity using produced gas from MH reserves and sends it to onshore. Its advantage is that hot water for dissociating MH can be served from waste heat of the gas turbine electric generating system (about 60% of total combustion heat) without using additional energy. In the integrated system, generated hot water is circulated MH dissociated region including the horizontal wells filled with hot water, named as hot water chamber, was generated to produce gas continuously. The gas production rate has the maximum peak just after breakthrough of injected water between horizontal wells, then it declined and gas was produced by almost constant rate. We have successfully developed the numerical model, and matched the history of physical gas production. Moreover, numerical simulations of gas production by the hot water injection into a Nankai Trough sediment layer model using a pair of the horizontal wells 500m in length were carried out for a methane hydrate reservoir of 20 m in layer thickness, 46% of average methane hydrate saturation, 100 and 25md in horizontal and vertical absolute permeabilities, respectively. The cumulative gas production is simulated as 5×106 std-m3 for initial two years. Furthermore, a new gas production scheme, which uses the horizontal wells in radian arrangement in a methane hydrate sediment layer with area of 1km×1km located at Nankai Trough, has been presented and evaluated with the numerical simulation as the cumulative gas production for 15 years is 1.3×108 std-m3..
65. Ferian Anggara, Kyuro Sasaki, Sandra Rodrigues, Yuichi Sugai, The Effect of Megascopic Texture on Swelling of a Low Rank Coal in Supercritical Carbon Dioxide, International Journal of Coal Geology, 125, 1, 45-56, 2014.05, Swelling experiments in supercritical CO2 have been conducted on two groups of samples of Miocene low rank coal with different megascopic textures (non-banded and banded) to address the different swelling behaviors. A block sample (30 × 10 × 10 mm) from core samples was used and a strain gauge was attached to the long axis of the sample block to measure the length of change. The actual maceral group compositions between these samples were similar and high in huminite. However, there is a subtle difference in suberinite and corpohuminite maceral where banded samples consistently have higher compositions compared to non-banded ones. The experimental results showed that banded coal samples tend to have anisotropic linear swelling where swelling perpendicular to bedding plane was always greater than that parallel. In contrast, non-banded samples showed more isotropic behavior without much preference to bedding plane orientation. The ratio of perpendicular to parallel swelling was around 1.28 and 1.05 for banded and non-banded coal samples, respectively. The difference in swelling characteristics was concluded as a result of different megascopic textures of coal samples with respect to bedding orientation..
66. Arif Widiatmojo, Kyuro Sasaki, Yuichi Sugai, Hiroyuki Tanaka, Kagemi Uchida, Hiroyuki Matsumoto, Assessment of Air Dispersion Characteristic in Underground Mine Ventilation: Field Measurement and Numerical Evaluation
, Process Safety and Environment Protection, http://dx.doi.org/doi:10.1016/j.psep.2014.04.001, 2014, 2014.04, An environmental safety of an underground mine strongly depends on its ventilation system. An efficient ventilation system provides fresh air, removes hazardous gasses or dust, and maintains temperature and humidity in appropriate levels. One of the most important factors in removing hazardous gasses or dust is the dispersion behaviour in the mine network. This factor determines the longitudinal spreading and the average air residence time of gasses or particulate matters throughout the mine. This paper describes tracer gas measurement in an underground mine and its utilization and analyse the dispersion characteristic by using numerical simulations. The concentration-time curve obtained from the measurement is simulated to evaluate the effective diffusion coefficient which reflects the general dispersion characteristic of an entire mine. The evaluated values of effective diffusion coefficient are then compared to other data from several studies. The diffusivities obtained in this study have been found to be higher than other analytical and empirical results. More research is still required to identify the main factors causing such higher diffusivities; however the results from the present work can be an important standpoint for future works. In addition, numerical simulation conducted in this research confirmed to be effective in detecting several leakage paths occurred in the mine ventilation network.
67. Chanmoly Or, Kyuro Sasaki, Yuichi Sugai, Masanori Nakano, Motonao Imai, Experimental Study on Foamy Viscosity by Analysing CO2 Micro-bubbles in Hexadecane, International Journal of Oil, Gas and Coal Engineering, 10.11648/j.ogce.20140202.11, 2, 2, 11-18, 2014.03, Continuous desorbing gas in the heavy oil generates lower viscosity with dispersing gas micro-bubbles. In this study, laboratory experiments were carried out to measure the viscosity of foamy hexadecane, typical component of heavy oil, and to investigate the CO2 gas micro-bubbles at ranged temperature of 20 – 50 °C and depressurization pressure of 1.0 – 6.0 MPa. Apparently, hexadecane mobility increases with increasing foam swelling. The viscosity ratio of foam vs. original hexadecane showed 0.90 – 0.70 with increasing foam swelling in the swelling range of 3.0 – 4.8%. The foam swelling is caused by dispersed gas micro-bubbles, and its viscosity was more reducible at either low temperature or high foam swelling based on present measurement results. The bubble distribution showed the large bubbles (approximately 50 μm in diameter) were coalesced but the micro-bubbles (approximately 5 μm in diameter) were stable under the shear of 1575 s-1, within 3 minutes of measuring. It shows that the micro-bubbles in smaller diameter have higher stability against the high shear rate. Therefore, generating foam by creating CO2 micro-bubbles is capable to make flow through the pore throats with viscosity reduction and improves oil recovery from non-mobile domain, such as aggregate and fine pores, by its swelling..
68. Yuichi Sugai, Tayfun Babadagli, Kyuro Sasaki, Consideration of An Effect of Interfacial Area between Oil and CO2 on Oil Swelling, Journal of Petroleum Exploration and Production Technology, 4, 1, 105-112, 2014.03.
69. Isty Adhitya Purwasena, Yuichi Sugai, Kyuro Sasaki, Petrotoga japonica sp. nov., a thermophilic, fermentative bacterium isolated from Yabase Oilfield in Japan, Archives of Microbiology, 10.1007/s00203-014-0972-4, 2014.03, A gram-negative, motile, fermentative, thermophilic bacterium, designated AR80T, was isolated from a high-temperature oil reservoir in Yabase Oilfield in Akita, Japan. Cells were rod-shaped, motile by means of polar flagella, and formed circular, convex, white colonies. The strain grew at 40–65 °C (optimum 60 °C), 0.5–9 % (w/v) NaCl (optimum 0.5–1 %), pH 6–9 (optimum pH 7.5), and elemental sulfur or thiosulfate serves as terminal electron acceptor. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain AR80T belonged to the genus Petrotoga and shared approximately 94.5 % sequence similarity with the type species of this genus. The G + C content of genomic DNA was 32.4 mol% while the value of DNA–DNA hybridization between the closest relative species Petrotoga miotherma and AR80T was 58.1 %. The major cellular fatty acids of strain AR80T consisted of 18:1 w9c, 16:0, and 16:1 w9c. Based on genetic and phenotypic properties, strain AR80T was different with other identified Petrotoga species and represents as a novel species, for which the name Petrotoga japonica sp. nov. is proposed. The type strain is AR80T (=NBRC 108752T = KCTC 15103T = HUT 8122T)..
70. Isty Adhitya Purwasena, Yuichi Sugai, Kyuro Sasaki, The Utilization of Natural Reservoir Brine in an Enrichment Culture Medium: An Alternative Approach for Isolation of Anaerobic Bacteria from an Oil Reservoir, Petroleum Science and Technology, 10.1080/10916466.2011.615365, 32, 7, 783-789, 2014.02, This study aims to suggest the new approaches of enrichment cultures using natural reservoir brine for enrichment culture medium in order to increase the bacterial population in the enrichment cultures and isolate novel thermophilic anaerobic bacteria from an oil reservoir. The results suggest that the brine-based culture medium should be sterilized by filtration to increase the number of bacterial population and CO2 should be supplied to culture medium to increase the possibility of isolating novel bacteria from oil reservoirs. One of the specific bacteria isolated under the presence of CO2 was a strain AR80 representing a novel bacterium within the genus Petrotoga on the basis of the phylogenetic analysis..
71. Maneeintr Kreangkrai, Tayfun Babadagli, Kyuro Sasaki, Yuichi Sugai, Analysis of Heavy Oil Emulsion-Carbon Dioxide System on Oil-Swelling Factor and Interfacial Tension by using Pendant Drop Method for Enhanced Oil Recovery and Carbon Dioxide Storage, International Journal of Environmental Science and Development, 10.7763/IJESD.2014.V5.462, 5, 2, 118-123, 2013.12, [URL], Heavy oil becomes more interest owing to oil prices and the huge amount of reserves. Steam injection is a common method for heavy-oil production with emulsion formation. Also carbon dioxide injection is applied for viscosity and interfacial tension reduction. CO2 becomes more important because of environmental concerns. CO2 storage in reservoirs like depleted oil wells becomes widespread. Hence, understanding the behavior of CO2 when it encounters emulsive heavy-oil is critical. In this work, the interfacial tension and oil-swelling factors of CO2 in oil and its emulsions are measured at 296 K and pressure from 0.5 to 1.5 MPa with water/oil ratio from 0.00 to 12.27 percent compared to original oil. The results show that the interfacial tension decreases at higher pressure ranging from 3.7 to 16.8 percent and water content from 10.3 to 22.6 percent. Furthermore, oil-swelling factors increase with pressure and water content up to 1.9 percent and 8.0 percent, respectively. These results are explained by absorption processes in that high pressure can serve as high driving force for CO2 solubility.
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72. Abu Bakarr Jalloh, Kyuro Sasaki, Geo-Statistical Simulation for Open Pit Design Optimization and Mine Economic Analysis in Decision-Making, Mine Planning and Equipment Selection, 2014, 9, 93-103, 2013.11.
73. Maneeintr Kreangkrai, Kyuro Sasaki, Yuichi Sugai, Investigation of the Effects of Parameters on Viscosities and Correlation of Heavy Oil and Stability of Its Emulsion, Journal of the Japan Institute of Energy, 92, 9, 900-904, 2013.09, [URL], Heavy oil becomes more popular as new energy sources due to the current oil prices and enormous amount of heavy oil reserves. However, heavy oil is difficult to produce because of its viscosity. Recently,thermal recovery, like steam injection, is a common method for heavy-oil production. During oil production with steam, crude oils are typically produced as water in crude-oil emulsions. This work investigates the effect of parameters such as temperature, water content in emulsions and shear rate on viscosities and stability of heavy oil and emulsions. It is demonstrated that the viscosity of the emulsions decreases with increasing temperature. Moreover, correlation of the effect of temperature on viscosity has been established and the numerical results get along well with the experimental results. Furthermore, the viscosity of oil enhances with higher water content. In addition, shear rate plays a significant role in viscosity reduction as shear rate increases. Also large shear stress is applied in order to break up the droplet and droplet sizes become smaller and it affects the stability of emulsion..
74. Kyuro Sasaki, Yuichi Sugai, Arif Widiatmojo, Hideo Naka, Tracer Gas Measurements of Effective Ventilation Airflow and Its Influence on Dust Concentrations in Underground Quarry, World Mining Congress 2013, 2013.08, Ventilation measurements were carried out in a shallow underground-quarry space with relatively large internal volume of 14,600m3 in order to evaluate its effective ventilation characteristics. Based on air velocity measurements with an ultrasonic anemometer in the exhaust airway connected to the space, it was found that the space was ventilated by natural ventilation airflow with intermittent changes in direction. It was difficult to measure the ventilation flow with typical methods of flow measurement provided from the intake portal and throughout the mine, because the cross-sectional areas of the openings was too large and the flow was variable. In the present study, a tracer gas method was applied to evaluate the effective ventilation airflow rate in the space. A photo-acoustic infra-red gas monitor, highly sensitive to sulphur hexafluoride (SF6) the tracer gas used, capable to of measuring down to 10 ppb, was set in the space to determine air exchange rates from gas concentration-time decay curves. The seasonal variations of airflow and thermal environment in the space were investigated through 13 sets of measurements taken during a year. Airborne rock dust concentrations were also measured at same time in the space. The correlations between the effective ventilation airflow rate, thermal environment and dust concentrations in the space were analyzed and are discussed based on the presented measurements taken during year. It has been concluded that the reason for the seasonal variations in effective ventilation flow and the dust concentration is mainly due to differences in air temperature in the space, as affected by the rock’s surface temperature and surface atmosphere air temperature. In summertime, the air temperature and associated air density difference generated lower natural ventilation flows resulting in higher dust concentrations..
75. Ferian Anggara, Kyuro Sasaki, Yuichi Sugai, Swelling Measurements of a Low Rank Coal in Supercritical CO2, Vol.2013-4, pp. 863-870, International Journal of Geosciences, 10.4236/ijg.2013.45080, 2013, 4, 863-870, 2013.07, [URL], In this report, coal swelling experiments using a visualization
method in the CO2 supercritical conditions were conducted on crushed coal samples. The measurement apparatus was designed specifically for the present swelling experiment using a visualization method. Crushed coal samples were used instead of block coal samples to shorten equilibrium time and to solve the problem of limited availability of core coal samples. Dry and wet coal samples were used in the experiments because there is relatively limited information about how the swelling of coal by CO2 is affected by water saturation. Moreover, some coal seams are saturated with water in initial reservoir conditions. The maximum volumetric swelling was around 3% at 10 MPa for dry samples and almost half that at the same pressure for wet samples. The wet samples showed lower volumetric swelling than dry ones because the wet coal samples were already swollen by water. Experimental results obtained for swelling were comparable with other reports. Our visualization method using crushed samples has advantages in terms of sample preparation and experimental execution compared with the other methods used to measure coal swelling using block samples..
76. Arif Widiatmojo, Kyuro Sasaki, Nuhindro Priagung Widodo, Yuichi Sugai, Discrete Tracer Point Method to Evaluate Turbulent Diffusion in Circular Pipe Flow, Journal of Flow Control, Measurement & Visualization, doi:10.4236/jfcmv.2013.12008, 2013, 1, 2013.07, Diffusion of a solute in turbulent flows through a circular pipe or tunnel is an important aspect of environmental safety. In this study, the diffusion coefficient of turbulent flow in circular pipe has been simulated by the Discrete Tracer Point Method (DTPM). The DTPM is a Lagrangian numerical method by a number of imaginary point displacement which satisfy turbulent mixing by velocity fluctuations, Reynolds stress, average velocity profile and a turbulent stochastic model. Numerical simulation results of points’ distribution by DTPM have been compared with the analytical solution for turbulent plug-flow. For the case of turbulent circular pipe flow, the appropriate DTPM calculation time step has been investigated using a constant β, which represents the ratio between average mixing lengths over diameter of circular
pipe. The evaluated values of diffusion coefficient by DTPM have been found to be in good agreement with Taylor’s analytical equation for turbulent circular pipe flow by giving β = 0.04 to 0.045. Further, history matching of experimental tracer gas measurement through turbulent smooth-straight pipe flow has been presented and the results showed good agreement..
77. Arif Widiatmojo, Kyuro Sasaki, Nuhindro Priagung Widodo, Yuichi Sugai, Johannes Shinaga, Haris Yusuf, Numerical Simulation to Evaluate Gas Diffusion of Turbulent Flow in Mine Ventilation System, International Journal of Mining Science and Technology, 10.1016/j.ijmst.2013.05.004, 23, 3, 349-355, 2013.07, technique is a method to analyze the airflow path, measure the airflow quantity, and detect any recirculation or leakages in underground mine. In addition, it is also possible to evaluate the axial gas diffusion of gas in turbulent bulk flow by utilizing the tracer gas data. This paper discussed about the measurement using tracer gas technique in Cibaliung Underground Mine, Indonesia and the evaluation of effective axial diffusion coefficient, E, by numerical simulation. In addition, a scheme to treat network flow in mine ventilation system was also proposed. The effective axial diffusion coefficient for each airway was evaluated based on Taylor’s theoretical equation. It is found that the evaluated diffusion coefficient agrees well with Taylor’s equation by considering that the wall friction factor, f, is higher than those for smooth pipe flow. It also shows that the value of effective diffusion coefficient can be inherently determined and the value is constant when matching with other measurements. Furthermore, there are possibilities to utilize the tracer gas measurement data to evaluate the airway friction factors..
78. Zhigang Li, Xiaoming Zhang, Yuichi Sugai, Jiren Wang, Kyuro Sasaki, Measurements of Gasification Characteristics of Coal and Char in CO2-Rich Gas Flow by TG-DTA, Journal of Combustion, http://dx.doi.org/10.1155/2013/985687, 2013, 15 pages, Article ID 985687, 2013.06, [URL], Pyrolysis, combustion, and gasification properties of pulverized coal and char in CO2-rich gas flow were investigated by using gravimetric-differential thermal analysis (TG-DTA) with changing O2%, heating temperature gradient, and flow rate of CO2-rich gases provided. Together with TG-DTA, flue gas generated from the heated coal, such as CO, CO2, and hydrocarbons (HCs), was analyzed simultaneously on the heating process.The optimum O2% inCO2-rich gas for combustion and gasification of coal or char was discussed by analyzing flue gas with changing O2 from 0 to 5%. The experimental results indicate that O2% has an especially
large effect on carbon oxidation at temperature less than 1100∘C, and lower O2 concentration promotes gasification reaction by producing CO gas over 1100∘C in temperature.The TG-DTA results with gas analyses have presented basic reference data that show the effects of O2 concentration and heating rate on coal physical and chemical behaviors for the expected technologies on coal gasification in CO2-rich gas and oxygen combustion and underground coal gasification..
79. Haruhiro Suzuki, Kyuro Sasaki, Yuichi Sugai, Total Evaluation on CCS System Against Geological Uncertainty and Troubles, Energy Procedia, 10.1016/j.egypro.2013.06.158, 37, 2738-2745, 2013.01, [URL], In this study, several simulations have been conducted on its system performance with and without CO2 buffer in the system. Optimum CO2 buffer volume has been presented based on economical evaluations for a commercial CCS model..
80. Very Susanto, Kyuro Sasaki, Yuichi Sugai, Teruhisa Yamashiro, Mixing Gas Migration in Fractured Rock Through Unsaturated and Water-saturated Layer: Result of a Pneumatic Gas Injection Test, Energy Procedia, 10.1016/j.egypro.2013.06.242, 37, 3507-3512, 2013.01, [URL], In this study mixing gas of CO2 and H2 was use to observe the gas migration during CO2 leakage based on natural analogue approach. We constructed a test field to investigate an monitoring system against CO2 leakage by tracer injection into five wells..
81. Ferian Anggara, Kyuro Sasaki, Yuichi Sugai, Mineral Dissolution/Precipitation During CO2 Injection into Coal Reservoir: A Laboratory Study, Energy Procedia, 10.1016/j.egypro.2013.06.605, 37, 6722-6729, 2013.01, [URL], The numerical simulation was only focused on the calcite that showed to dissolve in the near injection well area (higher pressure) as well as to precipitate at some distance from the injection well when injection of CO2 was stopped..
82. , [URL].
83. Yuichi Sugai, Kyuro Sasaki, Keigo Yoshimura, Shigenori Muta, Pilot Study on The Construction of Several Temperature-Controlled Multi-Purpose Pooms in a Disused Tunnel, Tunnelling and Underground Space Technology (Elsevier), 10.1016/j.tust.2012.06.009, 32, 180-189, 2012.09, Present study described one such pilot scheme involving the utilization of a disused tunnel of an uncompleted railway line that has been revamped as a facility housing temperature-controlled multi-purpose rooms. In all, four rooms were constructed and installed with both indoor and outdoor air conditioning units. Testing of the facility was conducted over a 1-year period to establish operating criteria and to monitor for operating stability. The four rooms were finally maintained at different constant-temperature regimes: cold (5 deg.C), cool (13 deg.C), mild (21 deg.C), and warm (32 deg.C) with such low power consumption of 0.80 kW because of the nature of the subterranean site. Compared with typical surface facilities, this facility offers an obvious advantage in lower energy consumption. Monitoring of the humidity in the rooms revealed that preventing evaporation from the bare soil surface in the tunnel was the more important factor in controlling humidity in this facility..
84. Zhigang Li, Xiaoming Zhang, Yuichi Sugai, Jiren Wang, Kyuro Sasaki, Properties and Developments of Combustion and Gasification of Coal and Char in a CO2-Rich and Recycled Flue Gases Atmosphere by Rapid Heating, Journal of Combustion, doi:10.1155/2012/241587, 2012, Article ID 241587, 11 pages, 2012.07, [URL], Combustion and gasification properties of pulverized coal and char have been investigated experimentally under the conditions of high temperature gradient of order 200°C·s−1 by a CO2 gas laser beam and CO2-rich atmospheres with 5% and 10% O2. The laser heating makes a more ideal experimental condition compared with previous studies with a TG-DTA, because it is able to minimize effects of coal oxidation and combustion by rapid heating process like radiative heat transfer condition. The experimental results indicated that coal weight reduction ratio to gases followed the Arrhenius equation with increasing coal temperature; further which were increased around 5% with adding H2O in CO2-rich atmosphere. In addition, coal-water mixtures with different water/coal mass ratio were used in order to investigate roles of water vapor in the process of coal gasification and combustion. Furthermore, char-water mixtures with different water/char mass ratio were also measured in order to discuss the generation ratio of CO/CO2, and specified that the source of Hydrocarbons is volatile matter from coal. Moreover, it was confirmed that generations of CO and Hydrocarbons gases are mainly dependent on coal temperature and O2 concentration, and they are stimulated at temperature over 1000°C in the CO2-rich atmosphere..
85. Airflow Measurements and Evaluation of Effective Ventilation Flow in an Underground Quarry using with Tracer Gas Method.
86. Arif Widiatmojo, Yuichi Sugai, Kyuro Sasaki, Numerical Simulation Method on Turbulent Gas Diffusion Phenomena in Mine Ventilation Network, 22nd World Mining Congress & Expo (istanbul, Turkey), Vol.I, 731-737, 2011.09.
87. Kyuro Sasaki, Ferian Anggara, Yuichi Sugai, Coal-Matrix Swelling by CO2 Adsorption and A Model of Permeability Reduction, 22nd World Mining Congress & Expo (istanbul, Turkey), Vol.II, 593-598, 2011.09.
88. Amin Yousefi-Sahzabi, Kyuro Sasaki, Saied Pirasteh, Hossein Yousefi, Yuichi Sugai, GIS aided prediction of CO2 emission dispersion from geothermal electricity production, Journal of Cleaner Production (Elsevier), doi.org/10.1016/j.jclepro.2011.06.009, 2011, 2, 1-7, 2011.07, [URL], CO2 is the dominant constituent of non-condensable gases in the steam phase of most geothermal fluids. This paper attempts to present the results of a study conducted to develop prediction modeling of CO2 dispersion in the surrounding atmosphere from a planned 50 MWe geothermal power plant prior to its production. Dispersion models are widely used for predicting future concentrations of environmental emissions on a range of geographic scales. The dispersion type for gases and their average removal rate depends on the meteorological conditions such as wind direction, wind speed, precipitation, atmospheric stability, and surface roughness and topography. Geographic Information System (GIS) capabilities were used for quality visualization of the model outputs and presenting an accurate numerical copy of the study area. The results by the prediction model show that the natural transfer of CO2 will be from the power plant toward east and northeast and CO2 concentration trends after the power plant utilization will be similar to the background conditions with minor changes. This dispersion test was carried out to validate and field test the GIS aided dispersion modeling approach described in the paper and the procedure may be applicable for other studies assessing the emission dispersion of pollutants from a point source.
.
89. Hiroyuki Kono, Kyuro Sasaki, Yuichi Sugai, Takashi Takahashi, Daisuke Ito, Takashi Okabe, Oil Drainage by CO2 Gas Diffusion, Dissolution and Foaming in Heavy Oil , World Heavy Oil Congress 2011, WHOC11-327, 2011.03.
90. Amin Yousefi-Sahzabi, Kyuro Sasaki, Ibrahim Djamaluddin, Hossein Yousefi, Yuichi Sugai, GIS modeling of CO2 Emission Sources and Storage Possibilities, Energy Procedia (Elsevier), doi.org/10.1016/j.egypro.2011.02.188, 4, Issue 1, 2831–2838, 10th International Conference on Greenhouse Gas Control Technologies(GHGT-10), 2011.02, This paper summarizes the capabilities of geographical information system (GIS) in CO2 capture and geological storage (CCS). GIS is emerging as a useful tool for the spatio-temporal analysis, techno-economic feasibility and environmental assessment of CCS projects. A review on the recent case studies reveals the applicability of geoinformation technology to the screening and analysis of emission sources, transportation and storage possibilities of CO2. This paper presents a survey on the methodologies, techniques and tools for modeling of the CO2 emission form stationary sources, CCS-GIS database development, spatial source-sink matching, and economic assessment. .
91. Maneeintr Kreangkrai, Kyuro Sasaki, Yuichi Sugai, Experiment and Numerical Simulation of Japanese Heavy Oil Recovery, Journal of Novel Carbon Resource Sciences, 2, pp.41-44, 2010.10.
92. Phung Quoc Huy, Kyuro Sasaki, Yuichi Sugai, Maneeintr Kreangkrai, Tayfun Babadagli, Numerical Simulation of CO2 Enhanced Coal Bed Methane Recovery for a Vietnamese Coal Seam, Journal of Novel Carbon Resource Sciences, 2, pp.1-7, 2010.10.
93. Amin Yousefi-Sahzabi, Kyuro Sasaki, Hossein Yousefi and Yuichi Sugai, CO2 Emission and Economic Growth of Iran, Mitigation and Adaptation Strategies for Global Change (Springer), 10.1007/s11027-010-9252-z, 2010.10, [URL].
94. Takafumi Yamakawa, Shinji Ono, Akinori Iwamoto, Yuichi Sugai, Kyuro Sasaki, A Gas Production System from Methane Hydrate Layers by Hot Water Injection and BHP Control with Radial Horizontal Wells, Proc. of 2010 Canadian Unconventional Resources and International Petroleum Conference , SPE-137801-PP (CD-ROM), 2010.10.
95. Phung Quoc Huy, Kyuro Sasaki, Yuichi Sugai, Fundamental Parameters for CO2 Enhanced Coalbed Methane Recovery in Deep And Unminable Coal Seams in Quangninh Coalfield, Vietnam, Proc. of International Conference on Advanced Mining for Sustainable Development, pp.419-432, 2010.09.
96. Phung Quoc Huy, Kyuro Sasaki, Yuichi Sugai, Satoshi Ichikawa, Carbon Dioxide Gas Permeability of Coal Core Samples and Estimation of Fracture Aperture Width, International Journal of Coal Geology (Elsevier) , 83-1, 1-10, 2010.06, [URL].
97. Kyuro Sasaki, Shinji Ono, Yuichi Sugai, Norio Tenma, Takao Ebinuma and Hideo Narita, Gas production from Methane Hydrate Sediment Layer by Thermal Stimulation with Hot Water Injection, 2010 Offshore Technology Conference, OTC-20592-PP (CD-ROM), 2010.05.
98. Tetsu Yasunami, Kyuro Sasaki, Yuichi Sugai, CO2 Temperature Prediction System in Injection Tubing Considering Supercritical Condition at Yubari ECBM Pilot-Test, http://dx.doi.org/10.2118/136684-PA, 49, 4, 44-50, 2010.04, The Japanese consortium to enhance CO2-ECBM carried out a pilot project on CO2 injection from 2002 to 2007 in the city of Yubari, Hokkaido, Japan. However, supercritical CO2 could not be obtained because of low CO2 injectivity and heat loss along the deep injection tubing. The absolute pressure and CO2 temperature at the bottomhole was approximately 15.5 MPa and 28°C, respectively. Therefore, it can be assumed that CO2 was injected into the coal seam in its liquid phase. Liquid CO2 is less permeable in the coal seam because of its high viscosity and the resultant swelling of the coal matrix to decrease permeability. This study provides a numerical system to predict CO2 flow characteristics of pressure, temperature, supercritical or liquid by considering heat transfer from the injector into surrounding casings and strata. This study focused on keeping supercritical CO2 in the tubing because the viscosity of supercritical CO2 is 40% less than that of liquid CO2. The CO2 temperature required to keep CO2 in its supercritical condition from the surface to the bottom was successfully predicted for various CO2 injection rates and electric heating powers.Finally, injected CO2 is expected to be supercritical at an injection rate of over 12 ton/d without any heating..
99. Contribution of Sabalan Geothermal Power Plant to Climate Change Mitigation.
100. Takashi Fujii, Hongfei Lin, Yoshiyuki Sato, Yuichi Sugai, Kyuro Sasaki, Hiroshi Inomata and Toshiyuki Hashida (2010); Investigation of CO2 Sorption Behavior in Rocks for CO2 Geological Storage, Journal of MMIJ, Vol.126 No.3, pp.84-94(in Japanese)..
101. Kyuro Sasaki, Shinji Ono, Yuichi Sugai, Norio Tenma, Takao Ebinuma, Hideo Narita, A Thermal Gas Production System from Methane Hydrate Layers by Hot Water Injection, Proc. 2010 SPE Oil and Gas India Conference and Exhibition (OGIC2010) (CD-ROM), SPE-129085-PP, 2010.01.
102. Kyuro Sasaki,Arif Widiatmojo,Gabriel Arpa,Yuichi Sugai (2009); Airflow Measurements and Evaluation of Effective Diffusion Coefficient in Large Scale of Mine Ventilation Network using with Tracer Gas Method, Journal of MMIJ, Vol. 125 No.12, pp. 614-620 (in Japanese)..
103. Kyuro Sasaki, Tetsu Yasunami, Yuichi Sugai (2009); A Numerical Model and Numerical Simulations in Consideration of Permeability Reduction by Coal-Matrix Swelling for CO2-ECBMR, Journal of MMIJ, Vol.125 No.12, pp.605-613(in Japanese)., [URL].
104. Amin Yousefi, Kyuro Sasaki, Yuichi Sugai and Hossein Yousefi, Future Climate Change Prediction by MAGICC/SCENGEN Model: A Case Study of Temperature Change for Tehran Province, Iran, Proc. of International Symposium on Earth Science and Technology 2009(Fukuoka, Japan), pp.303-308, 2009.12.
105. Isty A. Purwasena, Yuichi Sugai and Kyuro Sasaki, Estimation of the Potential of Microbial EOR by Using Oil-degrading Bacteria, Petrotoga sp.
Isolated from an Oilfield, Proc. of International Symposium on Earth Science and Technology 2009(Fukuoka), pp.543-549, 2009.12.
106. Arif Widiatmojo, Kyuro Sasaki, Gabriel Arpa, Yuichi Sugai and Nuhindro Priagung Widodo, A New Numerical Scheme for Discrete Tracer-Points Method to Simulate Gas Concentration
in Mine Ventilation Network Flow, Proc. of International Symposium on Earth Science and Technology 2009(Fukuoka), pp.113-118, 2009.12.
107. Gabriel Arpa, Kyuro Sasaki, Nuhindro Priagung Widodo, Arif Widatmojo, Yuichi Sugai, A Comparative Study on Ventilation Efficiency in Dead Spaces Along Mine Airways Based
on a Laboratory Model, and Mine Measurement, Proceedings of International Symposium on Earth Science and Technology 2009(Fukuoka), pp.114-124, 2009.12.
108. Hiroyuki Kono, Kyuro Sasaki, Yuichi Sugai, Kreangkrai Maneeintr, Takashi Takahashi, Daisuke Ito, Takashi Okabe, Solubility Measurements of Gases into Heavy Oil by PVT Process, Proceedings of International Symposium on Earth Science and Technology 2009(Fukuoka), 135-138, 2009.12.
109. Phun Quoc Huy, Kyuro Sasaki, Yuichi Sugai, Satoshi Ichikawa, Tayfun Babadagli, Visualization Study on Swelling of Coal Matrix in High Pressure CO2, Proc. of International Symposium on Earth Science and Technology 2009(Fukuoka), pp.145-150, 2009.12.
110. Phung Quoc Huy, Kyuro Sasaki and Yuichi Sugai, Gas Adsorption Capacity to Evaluate CO2 Sequestration Potential in Quangninh Coalfield, Vietnam, Mine Ventilation, Ed. D.C. Panigrahi Oxford & IBH Pub. , Vol. 2, 1031-1040, Proc. 9th International Mine Ventilation Congress (New Delhi, India), 2009.11.
111. Gabriel Arpa, Kyuro Sasaki, Arif Widiatmojo and Yuichi Sugai, Numerical Modeling of Diffusion Phenomena in Narrow Vein Mine Stope from Field Measurement and Scaled Laboratory, Mine Ventilation, Ed. D.C. Panigrahi Oxford & IBH Pub. , Vol. 2, 695-707, Proc. 9th International Mine Ventilation Congress (New Delhi, India), 2009.11.
112. Arif Widiatmojo, Kyuro Sasaki, Gabriel Arpa, Yuichi Sugai and Nuhindro P. Widodo, Simulation of Diffusion using Discrete Points Movement Method and Effect of Dead Space Volume in Mine Ventilation Airways, Mine Ventilation, Ed. D.C. Panigrahi Oxford & IBH Pub. , Vol. 2, 685-694, Proc. 9th International Mine Ventilation Congress (New Delhi, India), 2009.11.
113. Phung Quoc Huy, Kyuro Sasaki, Yuichi Sugai, Takashi Kiga, Masaki Fujioka, Tomio Adachi, Effects of SO2 and pH Concentration on CO2 Adsorption Capacity in Coal Seams for CO2 Sequestration With Considerations for Flue Gas From Coal-Fired Power Plants, JCPT (SPE), 48, 10, 58-63, 2009.10.
114. Kyuro Sasaki, Shinji Ono, Yuichi Sugai, Takao Ebinuma, Hideo Narita, Tsutom Yamaguchi, Gas Production System from Methane Hydrates Layers by Hot Water Injection using Dual Horizontal Wells, JCPT (SPE), 48, 10, 21-26, 2009.10, In this study, we investigate a system of gas production from methane hydrate layers involving hot water injection using dual horizontal wells. Physical and numerical models simulating the gas production process from methane hydrate layers within a hot water chamber are proposed.
Experiments with scaled two-dimensional physical models using an imitated hydrate layer (NaHCO3 ice formation) were performed to investigate fluid flow characteristics and production performance. The thermal simulator was used to simulate experimental chamber growth and field production. Numerical simulations for the processes were successfully performed with a two-component (water and oil or methane hydrates), three-phase (water, methane hydrates and methane gas) and three-dimensional model, matching the physical model. Results of the history-matched numerical simulations were in good agreement with data on production and chamber shapes obtained using the Intermediate3-Stone1 wettability model. Simulations of field production using dual horizontal wells 500 m in length were performed to evaluate cumulative gas production over 3 years of injection with 500 × 103 kg/day of hot water, which varied from 5 × 106 to 9 × 106 std m3. The production process appears economical, in view of the expected convective heat transfer from the chamber boundary and buoyancy force on dissociated methane gas..
115. Shinji Ono, Kyuro Sasaki, Yuichi Sugai, Takao Ebinuma, Tsutomu Yamaguchi, Hideo Narita (2009): Gas Production System from Methane Hydrate Layer by Hot Water Injection using Dual-Horizontal Wells-Predictions by Physical and Numerical Models-, Journal of JAPT, Vol.74-4, pp.334-343 (in Japanese).
, [URL].
116. Arif Watmojo, Kyuro Sasaki, N.P. Widodo, Gabriel. Arpa, Yuichi Sugai, Numerical Simulation of Diffusion in Mine Airways Using Discrete Tracer Movement Method And Effect Of Dead Spaces Area, Proc. of The 2nd Int ernat ional Symposium of Novel Carbon Resource Science Earth Resource Science and Technology (Institut Teknologi Bandung, Indonesia), pp.III-47-54, 2009.03.
117. Gabriel Arpa, Kyuro Sasaki And Yuichi Sugai, Numerical Modeling of Diffusion Phenomena in Narrow Vein Mine Stope from Field Measurement and Scaled Laboratory, Proc. of The 2nd International Symposium of Novel Carbon Resource Science Earth Resource Science and Technology (Institut Teknologi Bandung, Indonesia), 2009.03.
118. Isty A. Purwasena1, Yuichi Sugai and Kyuro Sasaki, A Preliminary Study on Microbial Enhanced Oil Recovery using CO2 as A Nutrient Source, Proc. of The 2nd Int ernat ional Symposium of Novel Carbon Resource Science Earth Resource Science and Technology (Institut Teknologi Bandung, Indonesia), pp.VII-1-7, 2009.03.
119. Takashi Fujii, Kyuro Sasaki, Yuichi Sugai, Toshiyuki Hashida, Measurements of CO2 Sorption on Rocks using a Volumetric Technique for CO2 Geological Storage, Energy Procedia (Elsevier), Volume 1, Issue 1, 3715-3722, 2009.02, In this study, permeabilities of the coal core sample, that was taken from -890m from surface by core drilling at Yuhbari CO2-ECBM test field (Japan CO2 Geo-sequestration in Coal Seams Project, JCOP), have been measured with gas and liquid CO2. The objective of this study was to show the behavior of the coal and rock permeabilities for liquid CO2 compared to gas, and furthermore, to assess swelling effect by the dimension change of hole 4mm in diameter made in the sample saturated with liquid CO2. It was found from visualization pictures that the area of the hole was reduced against time with about 7% after 78 hours..
120. Kyuro Sasaki, Tetsu Yasunami, Yuichi Sugai, Prediction model of Bottom Hole Temperature and Pressure at Deep Injector for CO2 Sequestration to Recover Injection Rate, Energy Procedia (Elsevier), doi.org/10.1016/j.egypro.2009.02.170, Volume 1, Issue 1, 2999-3006, Energy Procedia, Volume 1, Issue 1, February 2009, pp.2999-3006
9th International Conference on Greenhouse Gas Control Technologies(GHGT-9)(Washington DC, USA), 2009.02, The field test of CO2-ECBM was carried during 2003 to 2007 in order to evaluate technical feasibility of injecting CO2 into the coal seam while producing CH4 at Yubari City, Hokkaido, Japan. It aims to resolve global warming and to develop a system for injection and sequestration of CO2 into coal seams. The targeted coal seam is located about 900m below the surface. The absolute pressure at the bottom hole is approximately 15.5MPa and the CO2 temperature is about 28ºC before the injecting into the coal seam. Thus, CO2 is injected in liquid phase to the coal seam and supercritical condition of CO2 has not been satisfied due to heat loss along the deep injection well. Replacements of usual tubing pipes with thermal insulated tubings were applied, however the temperature at the bottom hole was still lower than the CO2 critical temperature. The project had a problem about decreasing injection rate after starting injection CO2. It was evaluated by analyzing the field test data that the maximum decreasing ratio of the coal seam permeability was 0.065 and permeability around injection well was became 6 times larger than the original one. We assumed that its reason is caused with swelling of the coal seam around the injection well by liquid CO2 injection. Present study has focused on the keeping supercritical CO2 in the tubing because viscosity of supercritical CO2 that is 40% smaller than that of liquid CO2. The CO2 temperature has been successfully predicted in order to keep CO2 in supercritical condition from the surface to the bottom for various CO2 injection rates and electric heater power. The minimum injection rate has been presented in order to keep CO2 in the supercritical condition at the bottom hole of the injection tubing. Injected CO2 is expected to be super critical over 12ton/day of injection rate without any heating in the tubing..
121. Yuichi Sugai, Tayfun Babadagli and Kyuro Sasaki, Measurement of Swelling of Crude Oil due to Carbon Dioxide Dissolution, Proc. of International Symposium on Earth Science and Technology 2008, pp.143-148, 2008.12.
122. Amin Yousefi, Hossein Yousefi, Kyuro Sasaki, Sachio Ehara, State of Power Generation and Environmental Issues in Iran, Proc. of International Symposium on Earth Science and Technology 2008, pp.473-480, 2008.12.
123. Machiko Oka, Yuichi Sugai, Kyuro Sasaki and Kazuhiro Fujiwara, Investigation of Autotrophic Bacteria and Oil-Degrading Bacteria Inhabit Oil Reservoir for Meor Without Injection of Organic Nutrients
, Proc. of International Symposium on Earth Science and Technology 2008, pp.71-76, 2008.12.
124. Nuhindro Priagung Widodo, Risono, Kyuro Sasaki,Yuichi Sugai and Rudy Sayoga Gautama , Application of Diffusion Coefficient to Simulate Gas Flow Concentration in Pongkor Mine, Proc. of International Symposium on Earth Science and Technology 2008, pp. 375-380, 2008.12.
125. Phung Quoc Huy, Kyuro Sasaki and Yuichi Sugai, Effects of SO2 and pH Concentration on CO2 Adsorption Capacity in Coal Seams, Proc. of International Symposium on Earth Science and Technology 2008, pp.91-98, 2008.12.
126. Gabriel Arpa, Arif Widiatmojo, Nuhindro Priagung Widodo, Kyuro Sasaki, Tracer Gas Measurement and Simulation of Turbulent Diffusion in Mine Ventilation Airways, Journal of Coal Science and Engineering(China), Springer, 14, 4, 523-529 , 2008.12, [URL], The effective diffusion coefficients in mine ventilation-flows had been obtained as 4 to 200 m2/s by matching the measured concentration-time curves with the advection-diffusion equation. The turbulent diffusion coefficients in the simple airways have good agreement with the equation proposed by Taylor. However, for complex airways in operating mines, the evaluated effective diffusion coefficients in the mines show higher values than that calculated by the Taylor’s equation. A numerical simulation model using with movements of discrete particles dosed into ventilation flows has been developed to simulate diffusion phenomena of gas or dust in mine airways. Numerical simulations had been conducted on distribution of tracers in single airways with ordinary profiles of mean velocity, velocity fluctuations and Reynolds stress. As one of results, long band of diffused particles is obtained at the single airway of 600 m in length, and large effective diffusion coefficient is evaluated as 20 m2/s..
127. Gabriel Arpa, Kyuro Sasaki and Yuichi Sugai, A Laboratory Shrinkage Stope Model to Study The Effective Turbulent Diffusion, Proc. of International Symposium on Earth Science and Technology 2008, pp. 365-374, 2008.12.
128. Gabriel Arpa, Arif Widiatmojo, Nuhindro Priagung Widodo, Kyuro Sasaki, Tracer Gas Measurement and Simulation of Turbulent Diffusion in Mine Ventilation Airways, Proc. of 3rd International Symposium on Modern Mining and Safety Techology(Fuxin, China), pp. 265-272, 2008.08.
129. Phung Quoc Huy, Kyuro Sasaki, Yuichi Sugai, Takashi Kiga, Masaki Fujioka, Tomio Adachi, Adsorption Capacity of Vietnum Anthracite Coal considering to CO2 Capture and Strage(CCS) from Coal-Fired Power Plant, Proc. of International Conference on Advances in Mining and Tunneling (Hanoi, Vietnam), pp. 391-402, 2008.08.
130. Tetsu Yasunami, Kyuro Sasaki, Yuichi Sugai, Masao Nako, Hideki, Kawabata (2008); Numerical Model of Temperature at Injection Tubing and Bottom Hole for Supercritical CO2 Injection into Deep Coal Seams, Journal of MMIJ, Vol. 124 No.6-7, pp.459-466 (in Japanese)..
131. Tetsu Yasunami, Kyuro Sasaki, Yuichi Sugai, Numerical Temperature Prediction System in Injection Tubing, Bottom Hole and Reservoir Condition for Supercritical CO2 injection into Deep Coal Seams, Proc. of CIPC/SPE GTS 2008 Joint Conference (Calgary, Canada), Paper#2008-104, 2008.06.
132. Phung Quoc Huy, Kyuro Sasaki, Yuichi Sugai, Takashi Kiga, Masaki Fujioka, Tomio Adachi, Effects of SO2 on CO2 Adsorption Capacity in Coal Seams for ECBM Considering to Flue Gas from Coal-fired Power Plant, Proc. of CIPC/SPE GTS 2008 Joint Conference (Calgary, Canada), Paper#2008-164, 2008.06.
133. Kyuro Sasaki, Shinji Ono, Yuichi Sugai, Takao Ebinuma, Tsutomu Yamaguchi, Hideo Narita, Evaluation of Gas Production Rate from Methane Hydrate Layers by a System with Multiple Dual Horizontal Wells, Proc. of CIPC/SPE GTS 2008 Joint Conference (Calgary, Canada), Paper#2008-163, 2008.06.
134. Nuhindro Priagung Widodo, Kyuro Sasaki, Yuichi Sugai, Rudy Sayoga Gautama, Diffusion Coefficient in Straight And Curved Airways, Proc. of 12th U.S./North American Mine Ventilation Symposium(Reno, USA), pp. 287-292, 2008.06.
135. Kyuro Sasaki, Arif Widiatmojo, Nuhindro Priagung Widodo, Gabriel Arpa, Yuichi Sugai, Numerical Simulation on Diffusion Phenomena in Mine Airways by using a Method of Discrete Tracer Movements, Proc. of 12th U.S./North American Mine Ventilation Symposium(Reno, USA), 287-292, 2008.06, [URL], Diffusion phenomena in mine airways are important to trace gas and dust introduced into mine ventilation flows. Authors have carried out tracer gas measurements to check mine ventilation using concentration-time curves measured in mine airways, however dispersion mechanism to enhance effective diffusion have not been cleared. A numerical model using discrete tracer points dosed into tube flow has been presented to simulate their movements in consideration of turbulent velocity profile and fluctuation. Numerical simulations have been carried out to predict distributions of dosed points in tube flows with turbulent velocity profile, turbulent intensity profile and Reynolds stress. The numerical simulation results show that a combination of turbulent velocity profile and fluctuation creates extremely large dispersion of points in longitudinal direction and concentration curve with long tail was observed. This dispersion by velocity profile and fluctuation contributes large effective diffusion coefficient compared with original diffusion coefficient dominating in uniform velocity fields. Furthermore, the effect of Reynolds stress on the concentration-time curves is discussed. .
136. Nuhindro Priagung Widodo, Kyuro Sasaki, Rudy Sayoga Gautama, Risono , Mine Ventilation Measurements with Tracer Gas Method and Evaluations of Turbulent Diffusion Coefficient, International Journal of Mining, Reclamation and Environment (Tayloy and Francis), 22, 1, pp. 60-69, 2008.03, [URL].
137. Takashi Fujii, Yuichi Sugai, Kyuro Sasaki (2008); Characteristics of Adsorption, Permeability and Swelling of Coal Relating to Liquid CO2 Sequestration into Coal Seams, Journal of MMIJ, Vol.123 No.11, pp.518-523 (in Japanese)..
138. Phung Quoc Huy, Kyuro Sasaki and Yuichi Sugai, Estimating of Coal Permeability Range by Small Area Measrurements with Few Numbers of Core Samples, Proceedings of 5th International Symposium on Earth Science and Technology, pp. 239-246, 2007.12.
139. Gabriel Arpa, Kyuro Sasaki and Yuichi Sugai, Kainantu Underground Mine Stope Ventilation Measurement Using Tracer Gas and Numerical Simulation, Proc. of 5th International Symposium on Earth Science and Technology(Fukuoka, Japan), 11-18, 2007.12.
140. Kyuro Sasaki and Yuichi Sugai, A New concept of Equivalent Oxidation Exposure-time for Low Temperature Spontaneous Combustion of Coal, Proc. of Coal-Gen2007(Milwaukee, USA), Paper Coal Yard Operations-1, 2007.08.
141. Yuichi Sugai, Kyuro Sasaki, Shigeyuki Takahata, Hideo Naka (2007); Characteristics of Fundamental Wall Material Containing a Green Tuff, Transaction of Society of Heating, Air-Coditioning and Sanitary Engeneers of Japan (SHASE)Vol.123, June, pp.1-10 (in Japanese)..
142. Nuhindro Priagung Widodo, Kyuro Sasaki, Yuichi Sugai, Rudy Sayoga Gautama and Arif Widiatmojo, A Laboratory Experiments for Tracer Gas Diffusion, Proc. of 4th International Workshop on Earth Science and Technology, pp. 83-90, 2006.12.
143. Charles Dindiwe, Kyuro Sasaki, Innovative Open Cast Design by BPITC Approach, Proc. of 4th International Workshop on Earth Science and Technology (Fukuoka, Japan), pp. 83-90, 2006.12.
144. Yuichi Sugai, Kyuro Sasaki, Shigeyuki, Takahata, Hideo Naka (2005), "Applicability of The TOWADA Stone to The Deodorizing and The Fertilizing Agents", Journal of Kotsuzai Shigen, Vol.37, No.147, pp.153-161 (in Japanese)..
145. Shinji Ono, Yuichi Sugai, Kyuro Sasaki, Takao Ebinuma, Tsutomu Yamaguchi, Hideo Narita, Gas Production System from Methane Hydrate Layer by Hot Water Injection using Dual-Horizontal Wells, Proc. 3rd International Workshop on Earth Science and Technology(Fukuoka, Japan), 55-62, 2005.12.
146. Yuichi Sugai, Kyuro Sasaki, Osamu Matsubaya, Hideo Naka, and Fujio Tanaka (2005); "The Abilities of Hinai-Green Tuff to Adjust pH and Activate Microorganisms", Journal of MMIJ, Vol.121, No.10&11, pp.513-520 (in Japanese)..
147. Jiro Yamatomi, Hiroshi Shimotori, Osamu Sakai and Kyuro Sasaki:"Underground Tests for Paste Backfilling at the Toyoha Mine and Energy-Cost Saving Effects of Paste Fill", Journal of MMIJ, Vol.121, No.7, pp.330-340,2005 (in Japanese)..
148. Kyuro SASAKI, Takashi Fujii, Shinji Yamaguchi, Kotaro Ohga, Koji Hattori and Yasuyuki Kishi (2004):"CO2 Gas Permeability and Adsorption of Coal Samples in consideration of CO2 Sequestration into Coal Seams", Journal of MMIJ, Vol.120, No.8, pp.461-468, 2004 (in Japanese)..
149. Kyuro Sasaki, Takashi Fujii, Characteristics of CO2 Gas Permeability and Adsorption of Coal Samples for CO2 Sequestration into Japanese Coal Seams, Greenhouse Gas Control Technologies, 10.1016/B978-008044704-9/50313-X, 2257-2261, 2004.09, This chapter describes adsorption capacity of CO2 on coal matrix and gas permeability necessary for a numerical modeling were measured with two sizes of core specimens and four sizes of coal specimens including crushed specimens, respectively. The effects of coal specimen sizes on CO2 gas absorption capacity and permeability are investigated. Coal seams have a significant ability of CO2 adsorption more than CH4 as approximately double based on some experiments reported. By utilizing this property, coal bed methane gas can be replaced with CO2 injected and produced as a clean energy. Furthermore, adsorption behaviors against saturated CO2 water have been measured to simulate CO2 adsorption in a coal seam with high water saturation. © 2005 Elsevier Ltd. All rights reserved..
150. Kyuro Sasaki, Charles Dindiwe, Tsuyoshi Adachi(2001); Optimization of Open Pit limit Designs by Newly BPITC Approach and Initial Feasibility Study using Block Grade Data Set Estimated by Geostatistical Simulation, Journal of MMIJ, Vol. 117, No.7,pp.604-612 (in Japanese)..
151. Hikari Fujii, Satoshi Akibayashi, Kyuro Sasaki, Hiroyuki Kosukegawa (2001): Numerical Analysis and Visualization Experiments of Groundwater Flow in a Borehole with a Cylindrical Obstacle, Journal of JAGH, Vol.117 No.7,pp.604-612 (in Japanese)..
152. Kyuro Sasaki, Satoshi Akibayashi, Nintoku Yazawa, Quang Doan, S. M. Farouq Ali, Experimental Modelling of The Steam-Assisted Gravity Drainage Process -Enhancing SAGD Performance with Periodic Stimulation of The Horizontal Producer-, SPE Journal, 2001, March, 189-197, 2001.03.
153. Kyuro Sasaki, Satoshi Akibayashi, Nintoku Yazawa, Quang Doan, S. M. Farouq Ali, Numerical and Experimental Modelling of The Steam-assisted Gravity Drainage (SAGD) Process, Journal of Canadian Petroleum Technology (JCPT), 10.2118/01-01-04, 40, 1, 44-50, 2001.01, For complex petroleum recovery processes, an experimental investigation is usually performed with a numerical simulation to study the recovery mechanism(s). In this paper, both physical and numerical simulations of the steam assisted gravity drainage (SAGD) process were performed. One of the objectives of the numerical investigation was to determine the match between umerical results with data generated from scaled model experiments. The Computer Modelling Group's (CMG) STARS? thermal simulator was used. Results from the numerical simulation were found to be in reasonable agreement with those obtained from the experiments for oil production rates, and cumulative oil production. In addition, the steam chamber volume and temperature distribution were also examined. ffects of different parameters, such as steam injection pressure, vertical separation between injection and production wells, nd reservoir thickness, on the performance of the SAGD process ere investigated. They were observed to have the same effects on both experimental and numerical results. The numerical simulator was also used to study the influence of rock and fluid properties, such as oil viscosity, permeability, porosity, and the mount of heat loss from the reservoir to the surroundings.
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154. Kyuro Sasaki, Satoshi Akibayashi, Sunao Konno, Characteristics of Drilling Fluids at Low Temperature Range and Heat Transfer Model between Casing Pipe and Strata, International Journal of Materials Engineering for Resources, 18, 2, 84-91, 2000.09.
155. Kyuro Sasaki, Satoshi Akibayashi, A Calculation Model for Liquid CO2 Injection into Shallow Sub-Seabed Aquifer, Annals of the New York Academy of Sciences, 912, 211-225, 2000.01, This study provided a model for calculating the aquifer transmissibility, the CO2 injection rate, the inner diameter of the injection well, and the number of wells for liquid CO2 disposal in the aquifer. The possibility of disposing liquid CO2 in an aquifer just beneath the sea floor was shown, based on the equilibrium lines in the pressure and temperature map. Our study focused on the feasibility of liquid CO2 disposal below the critical temperature because CO2 can be denser in the low-pressure range (below the critical temperature) than above the critical temperature. An aquifer about 200 m under the sea floor, at a water depth of around 500 m (700 m below the sea surface), will serve for liquid CO2 disposal. In the aquifer the absolute pressure is approximately 7.3 MPa, sea-floor temperature is about 4–6°C, and aquifer temperature is about 15–20°C. Therefore, it can be assumed that CO2 dissolves in the aquifer water, and liquid CO2 replaces the water. This means that under the previous conditions, more CO2 can be injected into the aquifer compared to supercritical conditions. Furthermore, by forming a cap of CO2 hydrates, the sediment between the sea floor and the aquifer, prevents CO2 leakage to the sea. Even without the cap, liquid CO2 and CO2 hydrates form at the sea floor, so the CO2 exerts no large environmental impact..
156. Kyuro Sasaki, Satoshi Akibayashi, Akihiro Hachiya, A Fundamental Design Criterion for Liquid CO2 Injection into Shallow Sub-seabed Aquifer, International Journal of Materials Engineering for Resources, 7, 1, 29-43, 1999.01.
157. Satoshi Akibayashi, Kyuro Sasaki, Fumio Sugimoto, Shinji Yamaguchi, Jiro Yamatomi, Kunsoo Kim, A Theoretical Approach for Estimating the Surface Area of a Rough-Walled Fracture from Well Logging Data, International Journal of Rock Mechanics & Minning Sciences, 34, 3-4, no.270, 1997.06, A theoretical approach is presented to estimate the surface area of a rough-walled fracture artificially induced in a hot dry rock. In this approach the concept of parallel-plate model, measured values of permeability, average fracture aperture obtained from the injection test and by the televiewer, are used. This approach was also applied numerically to analyze the transport, deposition and dissolution of silica in the non-isothermal problem when a cool water was injected into the hot dry rock fracture through the injection well. From the results of the analysis, the effect of fracture surface area on the dissolution and precipitation of silica in the fracture and the computational error in this approach was evaluated..
158. Kyuro Sasaki, Masaru Kiya, Three-dimensional Vortex Structure in a Leading-edge Separation Bubble at Moderate Reynolds Number, Journal of Fluids Engineering , 10.1115/1.2909510, 113, 9, 405-410, 1991.09, This paper describes the results of a flow visualization study which concerns three-dimensional vortex structures in a leading-edge separation bubble formed along the sides of a blunt flat plate. Dye and hydrogen bubbles were used as tracers. Reynolds number (Re), based on the plate thickness, was varied from 80 to 800. For 80 < Re < 320, the separated shear layer remains laminar up to the reattachment line without significant spanwise distortion of vortex filaments. For 320 < Re < 380, a Λ-shaped deformation of vortex filaments appears shortly downstream of the reattachment and is arranged in-phase in the downstream direction. For Re > 380, hairpin-like structures are formed and arranged in a staggered manner. The longitudinal and spanwise distances of the vortex arrangement are presented as functions of the Reynolds number..
159. Masaru Kiya, Kyuro Sasaki, Mikio Arie, Discrete-vortex Simulation of A Turbulent Separation Bubble, Journal of Fluid Mechanics, 10.1017/S0022112082002742, 120, 219-244, 1982.07, [URL], The discrete-vortex model is applied to simulate the separation bubble over a two-dimensional blunt flat plate with finite thickness and right-angled corners, which is aligned parallel to a uniform approaching stream. This flow situation is chosen because, unlike most previous applications of the model, the separation bubble is supposed to be strongly affected by a nearby solid surface. The major objective of this paper is to examine to what extent the discrete-vortex model is effective for such a flow..
160. Masaru Kiya, Kyuro Sasaki, Structure of A Turbulent Separation Bubble, Journal of Fluid Mechanics, 10.1017/S002211208300230X, 137, 83-113, 1983.12, [URL], Flow in the separation bubble formed along the sides of a blunt flat plate with right-angled corners has been studied in terms of extensive single- and two-point measurements of velocity and surface-pressure fluctuations..
161. Kyuro Sasaki, Masaru Kiya, Effect of Free Stream Turbulence on Turbulent Properties of a Separation Reattachment Flow, Bulltine of JSME, 10.1299/jsme1958.28.610, 28, 238, 610-616, 1985.04, [URL], Studied in this paper is the effect of free-stream turbulence on the turbulent structure of a separation bubble formed at the leading edge of a blunt plate with right-angled corners. The free-stream turbulence was introduced by a thin circular rod placed upstream of the plate along its stagnation streamline. This paper is sequel to the authors' previous papers (Kiya & Sasaki 1983, Kiya et al. 1984) in which time-averaged properties of the separation bubble are given in terms of the turbulence intensity at a reference point near an edge of the plate. The longitudinal and spanwise integral length scales of vortices in the separation bubble were given as functions of the free -stream turbulence intensity. The cross correlations between the surface-pressure and velocity fluctuations suggested that large-scale vortices are similar in shape independently of the free-stream turbulence intensity. Moreover, the maximum gradient of the time-mean surface-pressure profile and the longitudinal length scale of vortices in the reattaching zone..