Kyushu University Academic Staff Educational and Research Activities Database
Researcher information (To researchers) Need Help? How to update
Yuichi Sugai Last modified date:2019.06.23

Associate Professor / Department of Earth Resources Engineering
Department of Earth Resources Engineering
Faculty of Engineering


Graduate School
Undergraduate School


E-Mail
Homepage
http://reps.mine.kyushu-u.ac.jp/reps
Phone
092-802-3328
Fax
092-802-3328
Academic Degree
Dr of Engineering
Field of Specialization
Resources Production Engineering
Outline Activities
1) Estimation of the Potential of an Oil-Viscosity-Reducing Bacterium Petrotoga sp. Isolated from an Oil Field for MEOR
 An anaerobic oil-degrading thermophile, Petrotoga sp. AR80, was isolated from reservoir brine of an oilfield in Japan. This bacterium degrades long-chain hydrocarbons of crude oil into shorter-chain hydrocarbons in brine medium. Therefore, the oil viscosity can be decreased and the enhancement of oil recovery can be expected by this bacterium. The potential of this bacterium as a candidate for MEOR was estimated in this study. Some nitrogen source which is essential for bacteria should be injected into reservoir to stimulate the bacterial growth. To select a suitable brine medium for this bacterial activity on the reduction of crude oil viscosity, the numbers of nitrogen sources were evaluated. The highest growth rate was observed in medium contained yeast extract with maximum cell concentration in this medium was 10 times higher than that in other mediums. The influence of reservoir conditions such as temperature, salinity, and pressure on the bacterium was evaluated. This bacterium can grow and decrease oil viscosity at a temperature between 50 °C and 70 °C. The oil viscosity incubated with Petrotoga sp. AR80 was 46.3 %, 51.6 % and 65.9 % lower than control after 3 weeks incubation at 50 °C, 60 °C and 70 °C. In addition, the oil viscosity was 35.1 % lower than control at 70 °C and 800 psi. The result of GC chromatogram showed that this bacterium can convert and/or degrade various components of oil lead to depletion in heavier oil components and enrichment of light oil components respectively. Oil extracted from Oman, China and Canada can be utilized by this bacterium instead of Japanese oil. These results show that the isolated bacterium can be applied to a wide range of reservoirs for MEOR. In addition, this bacterium achieves economically feasible MEOR because it doesn’t need costly nutrients such as molasses which has been used as a nutrient in MEOR.

2) Microbial restoration of natural gas deposits with CO2 sequestration by indigenous hydrogen-producing bacteria and hydrogenotrophic methanogens
 CO2 sequestration into depleted oil reservoir has been expected as a method of reducing CO2 emission. Moreover, the authors focus on in-situ microbial conversion process of carbon dioxide into methane by hydrogenotrophic methanogens that inhabit oil reservoir universally. It is important for this process how to supply hydrogenotrophic methanogens with hydrogen for their methane production in reservoir. This study is aimed at searching for the oil-degrading and hydrogen-producing thermophilic bacteria (ODHPTB) which can produce hydrogen from oil in reservoir brine.
 Reservoir brine was extracted from 10 producing wells in Yabase oilfield in Japan. Indigenous bacteria in brine samples were incubated with sterilized oil under anaerobic conditions (10% CO2 balance N2) at 50oC and/or 75oC. Both the production of hydrogen and methane and the consumption of carbon dioxide were observed in almost all culture solutions after 2 months incubation. The maximum rate of hydrogen production was 20.9 Nml/L-medium/day.
 These culture solution and raw brine were inoculated into nutrient agar medium and incubated under anaerobic conditions at 50oC and 75oC. Microbial single colonies formed in the nutrient agar medium after 2 weeks incubation were picked and inoculated into sterilized brine including sterilized oil as a hydrogen source. More than 40 strains were isolated and incubated in the brine medium and 24 strains were observed to produce hydrogen from oil after 1 month incubation. The maximum rate of hydrogen production was 1.0 Nml/L-medium/day.
 These results show that the in-situ microbial conversion process of carbon dioxide and residual oil into methane using ODHPTB and hydrogenotrophic methanogens is promising. Moreover, the most talented ODHPTB that was isolated in this study can be injected into reservoir in order to stimulate the conversion of carbon dioxide into methane.

3) Numerical Prediction of Reservoir Souring Based on the Growth Kinetics of Sulfate-reducing Bacteria Indigenous to an Oilfield
 Seawater injection for oil recovery is frequently accompanied by souring because seawater contains sulfate related to the growth of sulfate-reducing bacteria (SRB). The mechanisms of reservoir souring vary depending on reservoir conditions such as species of SRB, organic substances that become nutrients for SRB, temperature, and so on. The purpose of this study is to predict the reservoir souring in an oilfield in which brine injection is planned. For this purpose, we performed chemical and microbiological analyses of the oilfield brine, kinetic studies of the growth of SRB indigenous to the brine, and numerical simulation studies on the reservoir souring in the oilfield. Several kinds of organic substances that can be nutrients for SRB were found in both production and injection brine collected in the oilfield. Three types of SRB were found in both brine samples by genetic analyses of DNA extracted from them. Bacterial cell number of SRB in the injection brine was ten times larger than that in the production brine. In addition, the most active growth of SRB was found in the injection brine supplemented with ethanol, therefore, the SRB inhabiting the injection brine was assumed to grow dominantly and generate hydrogen sulfide using sulfate and ethanol in the reservoir. On the basis of this mechanism, we derived an equation that calculated growth rate of the SRB with three variables: temperature, concentration of sulfate, and concentration of ethanol from the results of incubation experiments using the injection brine. A numerical simulator including the growth rate equation for the SRB was constructed by modifying our own simulator of Microbial EOR. The SRB grew and generated hydrogen sulfide around the injection well where temperature was decreased by injected brine. The results of the numerical simulation suggested that severe reservoir souring doesn't occur by the brine injection in the oilfield. Furthermore, the numerical simulation suggested that the reservoir souring can be prevented more surely by sterilizing the SRB in the injection brine, heating up the injection brine to 323K, or reducing sulfate in the injection brine.

4) Investigation of Microorganisms in Water-dissolved Natural Gas Fields for Preventing the Well Clogging
 The brine that is produced from water-dissolved natural gas reservoirs should be returned into reservoirs after the natural gas was separated to prevent the subsidence. However, reinjection capacities of reinjection wells decline gradually; therefore, their capacities should be maintained by backwashing process. Biofilm-like materials can be observed in solid materials that are produced by the backwashing from the reinjection wells. In this study, we investigated the relationship between microbial communities in water-dissolved natural gas reservoirs and the clogging of reinjection wells.
Brine samples were extracted from several places: production wellheads, sedimentation tanks below gas separators, sump pits below the recovery plants of iodine which is also extracted from brine as a natural resource, and wellheads and bottom holes of reinjection wells. Microbial community structures in brine samples were analyzed by genetic engineering techniques.
 Microbial community structures were changed drastically after the gas separators, at where the brine began to contact air, and the iodine recovery plants, at where sulfuric acid and oxidizer were added into brine for the recovery reactions. Both sulfate-reducing bacterium Desulfovibrio sp. and sulfur-oxidizing bacterium Sulfrimonas sp. were detected as dominant species from the bottom holes of the reinjection wells. Formation of microbial consortium and biofilms by those bacteria is well known in microbial corrosion. In addition, it is assumed that both oxygen and sulfate that are added through the surface process stimulate the formation of biofilms of those bacteria and it clogs the reinjection wells. Therefore, both deoxidization and desulfurization are expected to be effective for preventing the clogging the reinjection wells.
Research
Research Interests
  • Development of a Technology for In-Situ Recovery of Gold Using Iodide-Oxidizing Bacteria

    keyword : gold, Iodide-oxidizing bacteria, water-soluble natural gas, brine, iodide, iodine, triiodide, redox potential
    2017.10.
  • Consideration of methane gas recovery method from shallow gas hydrate deposits
    keyword : shallow gas hydrate deposits, hot water injection, subsidence, simulation, sand layer, directional well
    2017.04.
  • Construction of an experimental setup for estimating the spontaneous combustion coal
    keyword : coal, spontaneous combustion, oxygen, oxidation, heat generation, heat flux
    2016.04.
  • Estimation of IFT Reduction by a Biomass Material and Potential of Its Utilization for EOR
    keyword : Yeast, Cell wall, Interfacial tension, Enhanced oil recovery, Core flooding experiment
    2016.04.
  • Investigation of absorbing and desorbing behavior of CO2 and CH4 for enhanced coalbed methane recovery by CO2 injection
    keyword : Coal, Coalbed methane, Enhanced recovery, Cabon dioxide, Absorption, Desorption, Pressure, Mixed gas
    2015.04.
  • Consideration of an effect by dissolving gases on the interfacial tension between
    keyword : Gas, Dissolution, Interfacial tension, High pressure, Visualization, Pendant drop
    2015.04.
  • Fundamental investigation of an in-situ realtime method for monitoring subsurface bacteria
    keyword : Subsurface microorganism, Monitoring, In-situ, Real-time, Flow cytometry, Fluorescent, Scattered Light
    2015.04.
  • Experimental and Numerical studies on the Enhanced Oil Recovery Using Surfactin
    keyword : EOR, Core Flooding, Interfacial Tension, Sarfactin, Simulation
    2015.04.
  • Investigation of Indigenous Bacteria in Water-dissolved Natural Gas Fields and Control Technique for Them
    keyword : Water-dissolved natural gas, Microorganism, Brine, Well, Iodide Oxydizing Bacteria, Sulfate Resucing Bacteria, Methanogen
    2015.04.
  • Core Flooding Experiments for the Biostimulation Tyep Microbial Enhanced Oil Recovery Technbique
    keyword : Microorganism, Oil, MEOR, Core, Indigenous microorganism, Sabstrates
    2015.04~2018.03Microbial technology for production of mineral/hydrocarbon reserves is recognaized as a furture method with higher environmental and economical performance. I have investigated the functions of microorganisms sampled from mineral/hydrocarbon for resources production and environmental studies. In particular, organic nutrient such as molasses has been used for a nutrient of bacteria in Microbial EOR (MEOR), however, its cost is going up recently because it becomes to be a material for bio-ethanol. MEOR field test using molasses has been carried out in Jillin oilfield in China since 2000 and the current cost of Chinese molasses becomes three times higher compared with the cost at eight years ago. It will be difficult to use organic nutrients such as molasses for MEOR in the near future. The author suggests to use autotrophic bacteria and/or oil-degrading bacteria which can grow without sugars in MEOR. In this study, the potential of MEOR using these bacteria without injecting organic nutrients was estimated by investigating these bacteria inhabit oil reservoir using DNA analysis methods..
  • Development of new environment-purifying-material which consists of waste stone and effective microorganisms
    keyword : Effective microorganism, environment-purifying-material, Waste stone, Carrier, pH, Mineral, Porous media, Adsorption, Compost, Deodorant
    2012.04~2015.03Abilities of rock dusts to neutralize acid was shown in our laboratory experiments. Therefore, rock dusts will be very helpful to maintain pH appropriate for microbes for long time against decrease in pH caused by acid rain and/or acid metabolites of microbes. Based on this result, our research group suggests to utilize the rock dusts as a functional carrier for effective microbes of microbial materials. Because poultry farming is one of main animal husbandry around Ito-campus, an utilization of rock dusts as a carrier of a microbial material for promoting fermentation of poultry manure is studied..
  • Reservoir souring caused by sulfate-reducing bacteria indigenous to oilfield
    keyword : Sulfate reducing bacteria, Hydrogen sulfide, Specific growth rate, Simulation
    2012.10~2015.03.
  • Investigation of Indigenous Bacteria in Water-dissolved Natural Gas Fields for Preventing Microbial Clogging of Re-injection Wells
    keyword : Microorganism, restoration well, water-dissolved natural gas, Iodine, Brackish water, Clogging, Sulfate, dissolved oxygen, Bio-film
    2009.04~2013.03.
  • Studies on Enhanced Oil Recovery Method by Using Effective Microorganisms
    keyword : MEOR, Microorganism, Oil, PCR, DGGE, Petrotoga sp., Oil degradation, Viscosity
    2005.11~2014.03Microbial technology for production of mineral/hydrocarbon reserves is recognaized as a furture method with higher environmental and economical performance. I have investigated the functions of microorganisms sampled from mineral/hydrocarbon for resources production and environmental studies. In particular, organic nutrient such as molasses has been used for a nutrient of bacteria in Microbial EOR (MEOR), however, its cost is going up recently because it becomes to be a material for bio-ethanol. MEOR field test using molasses has been carried out in Jillin oilfield in China since 2000 and the current cost of Chinese molasses becomes three times higher compared with the cost at eight years ago. It will be difficult to use organic nutrients such as molasses for MEOR in the near future. The author suggests to use autotrophic bacteria and/or oil-degrading bacteria which can grow without sugars in MEOR. In this study, the potential of MEOR using these bacteria without injecting organic nutrients was estimated by investigating these bacteria inhabit oil reservoir using DNA analysis methods..
  • Basic Studies on the Microbial Conversion of CO2 into CH4 in Depleted Oil Reservoir by using Hydrogen-Producing Bacteria and Hydrogenotrophic Methanogens Inhabitting Oil Reservoir
    keyword : CO2, CH4, H2, Microorganism, Methanogen, Hydrogen-producing bacteria, Oil-degrading bacteria, CCS, Deplited oilfield
    2007.08~2013.03CO2 sequestration into depleted oil reservoir has been expected as a method of reducing CO2 emission. Moreover, I focus on in-situ microbial conversion process of carbon dioxide into methane by hydrogenotrophic methanogens that inhabit oil reservoir universally. It is important for this process how to supply hydrogenotrophic methanogens with hydrogen for their methane production in reservoir. This study is aimed at searching for the oil-degrading and hydrogen-producing thermophilic bacteria (ODHPTB) which can produce hydrogen from oil in reservoir brine. Reservoir brine was extracted from Yabase oilfield in Japan. Indigenous bacteria in brine samples were incubated with sterilized oil under anaerobic conditions (10% CO2 balance N2) at 50oC and/or 75oC. Both the production of hydrogen and methane and the consumption of carbon dioxide were observed in almost all culture solutions. These culture solution and raw brine were inoculated into nutrient agar medium and incubated under anaerobic conditions at 50oC and 75oC. Microbial single colonies formed in the nutrient agar medium after 2 weeks incubation were picked and inoculated into sterilized brine including sterilized oil as a hydrogen source. More than 40 strains were isolated and incubated in the brine medium and 24 strains were observed to produce hydrogen from oil after 1 month incubation. These results show that the in-situ microbial conversion process of carbon dioxide and residual oil into methane using ODHPTB and hydrogenotrophic methanogens is promising. Moreover, the most talented ODHPTB that was isolated in this study can be injected into reservoir in order to stimulate the conversion of carbon dioxide into methane..
Current and Past Project
  • Safety and environmental assessments during and after CO2 injection are important for geological CO2 storage. It is required to set up safety guideline and to evaluate long-term environmental changes. Study on environmental changes between past and present geological phenomena is also essential for geological storage. However, direct measurements during long-term changes are difficult, because the diffusion and dispersion rates of CO2 are expected to be small rate and the evaluation period is sometimes needed more than 1,000 years. One of possible answers for this problem is an approache by a natural-analogue study that carries measurements at relatively shallow sediments.
Academic Activities
Reports
1. Isty A. Purwasena, Yuichi Sugai, Kyuro Sasaki, Evaluation of Reservoir Condition Effects on the Reduction of Oil Viscosity by a Petrotoga strain Isolated from an Oilfield for MEOR
, 石油技術協会誌, 2010.09.
2. Recent advances and prospects in microbial Enhanced Oil Recovery (MEOR) -Present and future prospects for development of MEOR technology-.
3. Recent advances and prospects in microbial Enhanced Oil Recovery (MEOR) -Movement towards practical MEOR technology-.
4. Recent advances and prospects in Microbial Enhanced Oil Recovery (MEOR) -Outline of MEOR and microorganisms for MEOR -.
5. Development of a Functional Wall Material Using TOWADA Stone.
6. Development of a Environmental Material using the Effective Microorganisms and the Dust of TOWADA Stone.
Papers
1. Mochammad Andy Natawijaya, Yuichi Sugai, Ferian Anggara, CO2 microbubble colloidal gas aphrons for EOR application: the generation using porous filter, diameter size analysis and gas blocking impact on sweep efficiency, Journal of Petroleum Exploration and Production Technology (Springer), https://doi.org/10.1007/s13202-019-0680-3, 2019.05, The CO2 is regarded to be an excellent solvent for miscible flooding. However, it is still facing a main problem which is the high mobility. Microbubbles with their unique characters offer some advantages for CO2 EOR application. Different pore throat size filters were used to generate different dominant sizes of microbubbles that were injected into sandpacks under tertiary condition. Microscopic analysis was carried out to visualize the presence, stability and behavior of microbubbles inside the solution and porous media. The microbubbles with a dominant size of 10–50 µm showed additional 26.38% of oil recovery, showing their advantages over a larger dominant size of microbubbles up to 5.28% of oil recovery. The injection with larger microbubbles with a dominant size of 70–150 µm showed 27.5% of higher injection pressure than with a smaller dominant size of microbubbles, showing their advantage in gas blocking ability. In the heterogeneous porous media experiment, the recovery volume ratio between low- and high-permeability sandpacks was increased from 1:57 during water flooding to 1:4 during the CO2 microbubble injection with 74.65% of additional recovery from a low-permeability zone, showing the microbubble gas blocking capability to change the flow pattern inside heterogeneous porous media..
2. San Yee Khaing, Yuichi Sugai, Kyuro Sasaki, Myo Min Tun, Consideration of Influential Factors on Bioleaching of Gold Ore Using Iodide-Oxidizing Bacteria, Minerals (MDPI), https://doi.org/10.3390/min9050274, 9, 5, 274-285, 2019.05, Iodide-oxidizing bacteria (IOB) oxidize iodide into iodine and triiodide which can be utilized for gold dissolution. IOB can be therefore useful for gold leaching. This study examined the impact of incubation conditions such as concentration of the nutrient and iodide, initial bacterial cell number, incubation temperature, and shaking condition on the performance of the gold dissolution through the experiments incubating IOB in the culture medium containing the marine broth, potassium iodide and gold ore. The minimum necessary concentration of marine broth and potassium iodide for the complete gold dissolution were determined to be 18.7 g/L and 10.9 g/L respectively. The initial bacterial cell number had no effect on gold dissolution when it was 1×104 cells/mL or higher. Gold leaching with IOB should be operated under a temperature range of 30–35 °C, which was the optimal temperature range for IOB. The bacterial growth rate under shaking conditions was three times faster than that under static conditions. Shaking incubation effectively shortened the contact time compared to the static incubation. According to the pH and redox potential of the culture solution, the stable gold complex in the culture solution of this study could be designated as gold (I) diiodide..
3. Hung Vo Thanh, Yuichi Sugai, Kyuro Sasaki, Impact of a new geological modelling method on the enhancement of the CO2 storage assessment of E sequence of Nam Vang field, offshore Vietnam, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects (Taylor & Francis), https://doi.org/10.1080/15567036.2019.1604865, 1-15, 2019.04, This study proposed a new geological modelling procedure for CO2 storage assessment in offshore Vietnam by integrating artificial neural networks, cokriging and object-based methods. These methods could solve the limitations of well data that have not been addressed by conventional modelling. Petrel software was used to build a geological model for comparing conventional and new modelling workflows. Moreover, the Eclipse simulator was used for CO2 injection scenarios on the geological model of two workflows. The simulation results of CO2 flow response corroborated that the new modelling workflow by showing better performance than the traditional modelling workflow. Thus, in the selected CO2 storage sites, the new modelling workflow is preferred because it strongly enhances the CO2 storage evaluation..
4. San Yee Khaing, Yuichi Sugai, Kyuro Sasaki, Gold Dissolution from ore with Iodide-oxidising Bacteria, Scientific Reports (Nature), https://doi.org/10.1038/s41598-019-41004-8, 9, (2019) 9:4178, 1-11, 2019.03, Gold leaching from ore using iodide-iodine mixtures is an alternative to gold cyanidation. this study evaluated the ability of iodide-oxidising bacteria to solubilise gold from ore that was mainly composed of gold, pyrite, galena, and chalcopyrite. eight bacterial strains were successfully isolated from brine. Those strains were incubated in a liquid culture medium containing ore with a gold content of 0.26 wt.% and pulp density of 3.3 w/v% to evaluate their abilities to mediate the dissolution of gold. The gold was solubilised completely within 30 days of incubation in the iodine-iodide lixiviant solution generated by three bacterial strains. One strain, in particular, completed the dissolution of gold within 5 days of incubation and was identified as a member of the genus Roseovarius. thus, the possibility of bacterial gold leaching using iodide-oxidising bacteria was successfully demonstrated. Bioleaching gold with iodide would likely be more environmentally sustainable than traditional cyanide leaching. Further research is required to evaluate the techno-economic feasibility of this approach..
5. Eric O. Ansah,Yuichi Sugai,Pierre Ronald Nguele Odou,Kyuro Sasaki, Integrated microbial enhanced oil recovery (MEOR) simulation: Main influencing parameters and uncertainty assessment, Journal of Petroleum Science and Engineering (Elsevier), 10.1016/j.petrol.2018.08.005, 171, 784-793, 2018.12, The present study investigated the ability of a thermophilic anaerobic microbe (herein coded as AR80) for MEOR with the further objective to quantify the uncertainty of production forecast in terms of the cumulative probability distribution. A series of core flood experiments conducted in water-flooded Berea sandstone showed that up to 51% of initial oil-in-place was recovered when the plugs were treated with AR80 and shut-in for 14 days. Mainly, the oil recovery mechanisms were attributed to viscosity enhancement, wettability changes, permeability and flow effects. Matching the laboratory data using artificial intelligence: the optimized cumulative oil recovery could be achieved at an enthalpy of 894.2 J/gmol, Arrhenius frequency of 8.3, residual oil saturation of 20%, log of capillary number at microbe flooding stage of −1.26, and also depicted a history match error less than 3%. Therefrom, a sensitivity analysis conducted on reservoir shut-in period effect on oil recovery revealed that a relatively shorter shut-in period is recommended to warrant early incremental oil recovery effect for economical purposes. In addition, MEOR could enhance the oil recovery significantly if a larger capillary number (between 10−5 and 10−3.5) is attained. Per probabilistic estimation, MEOR could sustain already water-flooded well for a set period of time. This study showed that there is a 20% frequency of increasing the oil recovery by above 20% when a mature water-flooded reservoir is further flooded with AR80 for 2 additional years. Lastly, it was demonstrated herein that increasing the nutrient (yeast extract) concentration (from 0.1 to 1% weight) had less or no significant effect on the oil viscosity and subsequent recovery..
6. Yuichi Sugai,Yukihiro Owaki,Kyuro Sasaki,Fuminori Kaneko,Takuma Sakai, Numerical modelling of the growth of sulfate-reducing bacteria indigenous to an oilfield in Japan, Petroleum Science and Technology (Taylor & Francis), https://doi.org/10.1080/10916466.2018.1496102, 36, 19, 1597-1604, 2018.09, We performed kinetic studies of the growth of sulfate-reducing bacteria (SRB) indigenous to the water in an oilfield in Japan. The SRB growth was most active in injection water supplemented with ethanol; therefore, the SRB inhabiting the injection water of the reservoir were assumed to grow predominantly by assimilating sulfate and ethanol and generating H2S. Based on this mechanism and the results of incubation experiments in the injection water, we derived numerical models that calculate the growth rate and H2S generation of the SRB under three variables (temperature, sulfate concentration, and ethanol concentration)..
7. Eric O. Ansah,Yuichi Sugai,Kyuro Sasaki, Geological tectonics and physio-chemical metrics as screening criteria for MEOR applicability in West Africa transform regional oil wells - a review, International Journal of Petroleum Engineering, http://dx.doi.org/10.1504/IJPE.2018.093164, 3, 2, 116-137, 2018.07, Primarily, most oil wells in the West Africa transform region are produced using water or water alternating gas. This is believed to be unsustainable going forward. Also, though the region contributes less to global greenhouse emission, global warming effects in the region cannot be undermined. Microbial enhanced oil recovery (MEOR) has been proven worldwide to be environmentally friendly as well as less costly to develop. Despite the advantages of MEOR over other oil recovery methods, operating companies in the region are yet to apply this bespoke technology. Therefore, this study reviews the potential applicability of MEOR process to West African oil fields comparing the geology and physiochemical properties to major oil fields in South America (where MEOR has been previously applied). Applying MEOR in the region could be a major step towards improving production of new oil wells and enhancing sustainability of old oil wells..
8. Eric O. Ansah,Yuichi Sugai,Kyuro Sasaki, Modeling microbial-induced oil viscosity reduction: Effect of temperature, salinity and nutrient concentration, Petroleum Science and Technology (Taylor & Francis), 10.1080/10916466.2018.1463253, 1-7, 2018.05, 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..
9. Isty Adhitya Purwasena,Yuichi Sugai, The analysis of bacterial diversity in high thermic-low salinity Oil Reservoirs prior to Microbial Enhanced Oil Recovery field test, Journal of Engineering and Applied Sciences, 10.3923/jeasci.2018.4104.4112, 13, 11, 4104-4112, 2018.01, Nutrition injection in Microbial Enhanced Oil Recovery (MEOR) process might stimulate not only desirable microorganisms but also the undesirable ones. Therefore, studying the properties of bacterial community in reservoir prior to field test is a critical step in MEOR process. In this study, bacterial communities from high thermic and low salinity reservoirs located in Japan, China and Indonesia were characterized by 16S rDNA sequence analysis. Bacterial genomic DNAs were extracted from produced water samples and their sequences were evaluated by genetic fingerprinting based approach. PCR-DGGE analyses showed multiple bands in all produced water samples which indicated high bacterial diversities. Sequences identified in this study were mainly related to only five phyla, i.e., Bacteroidetes, Thermotogae, Defferibacteres, Firmicutes and Proteobacteria, suggesting that phylotype richness is low in oil reservoirs. One sequence of Bacteriodetes-affiliated bacteria which showed 99% similarity with Bacteriodales bacterium 5bM was retrieved from DGGE results of all oilfields. This result showed that, Bacteriodetes can grow well in Indonesia, Japan and China oilfield, making it the best bacterial candidate for MEOR field test. Results showed in this study revealed that finger printing is a considerable technique for microbial screening prior to MEOR field test application..
10. Evan Rosyadi Ogara, Yuichi Sugai, Kyuro Sasaki, Ferian Anggara, The Effect of Coal Characteristics on Adsorption and Desorption Gas at Indonesia Low Rank Coal, International Symposium on Earth Science and Technology 2017, 472-477, 2017.11.
11. Yuichi Sugai, Junpei Mikumo, Keita Komatsu, Kyuro Sasaki, Experimental Investigation on the Availability of Yeast Cell Wall as an Interfacial Tension Reducer for Enhanced Oil Recovery, Journal of Petroleum & Environmental Biotechnology, 10.4172/2157-7463.1000329, 8, 3, 1-6, 2017.06, We studied on the availability of residue of squeezed beer yeast whose principal component is yeast cell wall for enhanced oil recovery as an interfacial tension reducer. The cell wall solution was hydrothermally treated in order to elute amphiphilic substances such as phospholipids, proteins, and fatty acids from the cell wall to the solution under different conditions such as concentration of the cell wall, temperature and time of the hydrothermal treatment, and salinity. The cell wall solution which was hydrothermally treated with crude oil was also applied to the measurement of interfacial tension between the solution and crude oil. The interfacial tension was reduced with decrease in salinity and increase in concentration of the cell wall and temperature of the hydrothermal treatment. The time of hydrothermal treatment didn't have much influence on the interfacial tension reduction. The capability of the cell wall solution which had been hydrothermally treated with crude oil to reduce the interfacial tension became larger than that of the cell wall solution which had been hydrothermally treated without crude oil. It was suggested that those interfacial tension reductions were brought by phospholipids and proteins eluted from the cell wall. Core flooding experiments were carried out by injecting the cell wall solution which had been hydrothermally treated with and without crude oil after the water flooding as the primary oil recovery. 2.0% and 1.2% of original oil in place was additionally recovered by injecting the cell wall solution which had been hydrothermally treated with and without crude oil respectively. These results support an advantage of process injecting the cell wall solution without hydrothermal treatment into high temperature oil reservoir. The injection of the cell wall solution can be a promising EOR which has both high cost performance and low environmental load..
12. San Yee Khaing, Sugeng Sapto Surjono, Jarot Setyowiyoto, Yuichi Sugai, Facies and Reservoir Characteristics of the Ngrayong Sandstone in the Rembang Area, Northeast Java (Indonesia), Open Journal of Geology, 10.4236/ojg.2017.75042, 7, 5, 608-620, 2017.05, The Rembang area is a well-known prospective region for oil and gas exploration in Northeast Java, Indonesia. In this study, the reservoir characteristics of the Ngrayong Sandstone were investigated based on outcrops in the Rembang area. Petrological, mineralogical, petrophysical and sedimentological facies analyses were conducted. These sandstones are grain- and matrix supported, and composed of very fine to medium, sub-angular to poorly-rounded, moderately to very well-sorted sand grains. These sandstones are mainly composed of quartz, orthoclase, plagioclase, and micas with minor amounts of clay minerals, and therefore are predominantly classified as sub-lithic arenite and sub-felds pathicarenite. Petrographic observations and grain size data indicate that these sandstones are texturally quite mature, based on their good -sorting and the occurrence of minor amounts of matrix clays. Common clays in the samples include illite, smectite, kaolinite, and gibbsite. The porosity of the Ngrayong sandstones ranges from 25.97% to 40.21%, and the permeability ranges from 94.6 to 3385 millidarcies. Thus, these sandstones exhibit well to excellent reservoir qualities. Eight lithofacies were identified from five measured stratigraphic sections, and are dominated by foreshore and tide-dominated shoreface facies. The Ngrayong sequence shows a single transgressiveregressive cycle. Cross-bedded sandstone and massive sandstone are identified as the most promising potential reservoir facies based on their characteristics in outcrops, their lateral and vertical distributions, their sedimentological characteristics and their petrophysical properties..
13. Minoru Saito,Yuichi Sugai,Kyuro Sasaki,Yoshifumi Okamoto,Chencan Ouyang, Experimental and Numerical Studies on EOR Using a Biosurfactant, the Abu Dhabi International Petroleum Exhibition and Conference 2016, SPE-183496-MS, 2016.11, The EOR potential of a biosurfactant was evaluated through core flooding experiments and numerical simulation in this study. The biosurfactant which was called surfactin was generated by a microorganism belonging to Bacillus species. The EOR potential of surfactins has been already reported by previous papers, however, that of surfactins can be different depending on their making process such as the conditions of incubation, extraction, purification, etc. This study used a surfactin which was made by Kaneka corporation's original techniques.
Core flooding experiments were carried out under ambient temperature and pressure to evaluate the EOR potential of the surfactin. Berea sandstone cores whose permeability was 50 md were used in this study. The surfactin solution was injected into cores after water flooding. 3 experiments were carried out by injecting surfactin solution whose surfactin concentration was 0.3 %, 0.03 % and 0.003 % respectively. An experiments were carried out by injecting the culture solution which had been diluted so that the surfactin concentration was 0.3 %. 4 experiments were carried out by injecting sodium dodecyl sulfate (SDS) solution which had been supplemented with a slight amount of surfactin or the culture solution. An injection was continued until oil was not produced completely.
Higher oil recovery was obtained by injecting higher concentration of surfactin. 13.6 % of original oil in place (OOIP) was recovered by injecting 0.3 % of pure surfactin solution, whereas 6.3 % of OOIP was recovered by injecting 0.3 % of pure SDS solution. 0.27 % of SDS solution which was supplemented with surfactin whose concentration was 0.03 % could recover 14.7 % of OOIP. 23.9 % of OOIP could be recovered by injecting the culture solution which was diluted by 16 times so that the surfactin concentration was 0.3 %. Enhancement of oil recovery which was obtained by injecting SDS solution supplemented with the culture solution was a little lower than that with pure surfactin.
The EOR potential of surfactin is quite higher than that of SDS. It was shown that the surfactin can be useful as a cosurfactant for SDS. Culture solution of the microorganism demonstrated much higher EOR potential than pure surfactin, therefore, it may include effective components other than the surfactin. Utilization of the culture solution is economically advantageous..
14. Yuichi Sugai, Keita Komatsu, Kyuro Sasaki, Estimation of IFT Reduction by a Biomass Material and Potential of Its Utilization for EOR, Society of Petroleum Engineers (SPE) Asia Pacific Oil and Gas Conference and Exhibition, SPE-176490-MS, 2015.10, Surfactant injection is one of the most effective EOR techniques. Chemical surfactants however pose a few problems such as their high cost and low-degradability. We study on the utilization of biomass such as agricultural fertilizer mainly comprising the residue of squeezed beer yeast for EOR as an alternative of chemical surfactants because crude oil can be completely miscible with the fertilizer solution. The fertilizer can be stably supplied at a low cost because it is a waste of beer brewing industry and is only used for an animal feed additive so far. Its retail price is approximately 1 USD/kg in Japan.
We semi-quantitatively estimated the interfacial tension (IFT) between the fertilizer solution and crude oil by the oil displacement test. Concentration of the fertilizer was varied between 10 to 50 g/L. The fertilizer solution to which sodium chloride was added at a concentration of 10 to 40 g/L was hydrothermally treated at 60, 80, 100 or 120 ºC for 10, 20, 30, 45 or 60 minutes respectively before the tests. The fertilizer solution to which crude oil was added at a ratio of 1 % was also hydrothermally treated at 120 ºC for 20 minutes. Solution of surfactin which was a commercial biosurfactant was used as a
standard of the IFT.
The IFT was reduced with the decrease in salinity and increase in concentration of the fertilizer and temperature of the hydrothermal treatment. Time of the hydrothermal treatment was preferably 30 minutes or less for the IFT reduction. The capability of 50 g/L of fertilizer solution to reduce the IFT was almost same as the capability of 0.2 g/L of the surfactin solution. Because the fertilizer solution comes into contact with residual oil under high temperature in oil reservoir, IFT between the solution and crude oil can be expected to be reduced in-situ.
Core flooding experiments were carried out by injecting the fertilizer solution after the water flooding as the primary oil recovery. 1.2 % of original oil in place was additionally recovered by injecting 50 g/L of the fertilizer solution after the water flooding. The fertilizer should be biodegradable because it is a microbially-derived substance. In addition, because the IFT reduction was observed after the hydrothermal treatment of the fertilizer solution, the fertilizer should be effective even in the reservoir whose temperature is high such as 120 ºC at which chemical surfactants may be deactivated. From those results, the injection of the fertilizer solution can be a promising EOR which has both high cost performance, low environmental load and high versatility..
15. Yuichi Sugai, Very Susant, Kyuro Sasaki, Ryo Mori, Spectrophotometric determination of pH change of formation water under high CO2 pressure using a mixed pH indicator, Journal of MMIJ(資源・素材学会), 131, 8,9, 518-523, 2015.08, In geologic CO2 sequestration, the pH of formation water may be decreased due to CO2 dissolution, which may cause the change of porosity and permeability of reservoir rock. The pH changes of formation water are widely varied depending on CO2 pressure and the content of substances having pH buffering action, therefore, it is important to determine the wide range of pH change of various types of formation water under the various CO2 pressure conditions.
We considered a determination method of pH change of various types of formation water under the various CO2 pressure conditions based on the spectrophotometry using a windowed high-pressure cell and a mixed pH indicator consisting of 4 single pH indicators. The well-defined absorption peaks were found at the wavelength of 614 nm or 444 nm when the pH of the solution was ≥5.6 or <5.6 respectively, therefore, two different calibration curves were derived from the absorbance of standard pH buffer solutions at each wavelength. The validity of this method was confirmed by an experimental result that the pH change of deionized water under 0.1 MPa CO2 pressure had been determined accurately by this method.
We carried out experiments on this method using the real formation water samples which contained bicarbonate ion having pH buffering action with different concentration under various CO2 pressure. The results of the experiments demonstrated that this method is capable of determining the pH change of various types of formation water under various CO2 pressure conditions.
.
16. Yuichi Sugai, Keita Komatsu, Kyuro Sasaki, Kristian Mogensen, Martin Vad Bennetzen, Microbial-Induced Oil Viscosity Reduction by Selective Degradation of Long-Chain Alkanes, Abu Dhabi International Petroleum Exhibition and Conference, SPE-171850-MS, 2014.11.
17. Isty Adhitya Purwasena, Yuichi Sugai, Kyuro Sasaki, Estimation of the potential of an anaerobic thermophilic oil-degrading bacterium as a candidate for MEOR, Journal of Petroleum Exploration and Production Technology (Springer), 10.1007/s13202-013-0095-5, 4, 2, 189-200, 2014.06, We investigated the decrease in oil viscosity caused by the biodegradation of crude oil by a bacterium (AR80) isolated from an oil reservoir, and estimated the potential for this bacterium for use in microbial enhanced oil recovery (MEOR). AR80 degraded long-chain n-alkanes preferentially, and anaerobically increased the ratio between the short-chain and long-chain n-alkane concentrations in the crude oil. The long-chain n-alkane metabolism by AR80 decreased the oil viscosity. AR80 grew well in a reservoir of brine supplemented with yeast extract, and decreased the oil viscosity to approximately 60% of its original value. Adding a small amount of yeast extract (0.05 g/L) was necessary to stimulate the AR80 activity. MEOR can, therefore, be achieved using AR80 without incurring excessive costs. AR80 can grow at temperatures up to 80 °C, and it grows well at between 50 °C and 70 °C. AR80 can grow at a salinity of up to 90 g/L, and it grows well at a salinity of less than 30 g/L. The AR80 activity was not affected very much by high pressures (such as 6.0 MPa). Core flooding experiments were performed by injecting AR80 (in brine supplemented with yeast extract) into Berea sandstone cores. Gas chromatography analysis of the effluent oil suggested that long-chain n-alkanes in the residual oil were preferentially degraded by the AR80 in the porous rocks. The core flooding experiments showed that the AR80 activity in the porous rocks caused the oil recovery to be enhanced, so AR80 could be a suitable candidate for MEOR..
18. Yuichi Sugai, Yukihiro Owaki, Kyuro Sasaki, Fuminori Kaneko, Takuma Sakai, Numerical Prediction of Reservoir Souring Based on the Growth Kinetics of Sulfate-reducing Bacteria Indigenous to an Oilfield, Society of Petroleum Engineers (SPE) International Oilfield Corrosion Conference and Exhibition, 10.2118/169629-MS, SPE-169629-MS, 2014.05.
19. Isty Adhitya Purwasena, Yuichi Sugai, Kyuro Sasaki, Petrotoga japonica sp. nov., a thermophilic, fermentative bacterium isolated from Yabase Oilfield in Japan, Archives of Microbiology (Springer), 10.1007/s00203-014-0972-4, 196, 5, 313-321, 2014.05.
20. 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 (Springer), 10.1007/s13202-013-0085-7, 4, 105-112, 2014.03, Oil swelling is an important phenomenon in CO2–EOR. According to various studies in the past, the degree of oil swelling depends on the partial pressure of CO2, temperature, and oil composition. However, we expect that other factors, such as oil saturation, capillary pressure, and grain size of reservoir rock must be also considered in evaluating oil swelling because they may influence the interfacial area between oil and CO2, which affects the dissolubility of CO2 in oil. Therefore, we had made clear the effect of the interfacial area on oil swelling in this study.
Oil and CO2 were injected into a small see–through windowed high–pressure cell and oil swelling was observed under a microscope. The swelling factor increased with the increase of the specific interfacial area between oil and CO2. Moreover, oil swelling in porous media was observed by using micro–models which had been made of 2 different diameter glass beads. Swelling factor in fine beads micro–model became larger than that in coarse beads micro–model whose interfacial area between oil and CO2 was smaller than that of fine beads micro–model. Therefore, the swelling factor is expected to be larger with an increase in the interfacial area in porous media. These results suggest that the oil swelling should be expressed as a function of oil saturation, capillary pressure, and grain size of reservoir rock which are related to the interfacial area as well as the partial pressure of CO2, temperature, and oil composition.
.
21. Isty A. Purwasena, Yuichi Sugai, Kyuro Sasaki, Utilization of Natural Reservoir Brine in Enrichment Culture Medium: An Alternative Approach for Isolation of Anaerobic Bacteria from an Oil Reservoir, Petroleum Science and Technology (Taylor & Francis), 10.1080/10916466.2011.615365, 32, 7, 783-789, 2014.02, The successful enrichment, isolation, and cultivation of prokaryotes are considerably dictated by the selection of appropriate growth media and incubation conditions. In this study, the utilization of natural reservoir brine to enrich and isolate anaerobic thermophilic bacteria from an oil reservoir was observed. The genetic diversity of the bacterial population present in the brine water was subsequently evaluated using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). In addition, indigenous bacteria that grew in high CO2 concentrations were isolated for examination. We compared the effects of two sterilization methods (filtration and autoclaving) and three gas combinations (pure N2, CO2/N2 (1:9), and pure CO2) injected into the headspace of the medium solution on the cultures. The result demonstrated that the diverse gas composition of the headspace of enrichment culture medium consisting of filtered brine could be one approach to stimulating the growth of physiologically distinct types of microorganisms..
22. Yuichi Sugai, Kyuro Sasaki, Ryo Wakizono, Yasunori Higuchi, Noriyuki Muraoka, Considerations on the possibility of microbial clogging of re-injection wells of the wastewater generated in a water-dissolved natural gas field, International Biodeterioration & Biodegradation (Elsevier), http://dx.doi.org/10.1016/j.ibiod.2012.10.003, 81, 35-41, 2013.07, Brine produced from water-dissolved natural gas reservoirs should be returned to the reservoirs after the resources are recovered to prevent land subsidence. However, the ability to re-inject the brine gradually decreases and is only rectified by carrying out backwashing treatment of re-injection wells. Because the brine contains high levels of iodine also, it is also recovered from the brine using sulfuric acid and oxidizing agents. These chemicals may stimulate the growth of microorganisms that may cause the clogging. In this study, we used column experiments to investigate the possibility of the microbial clogging.
Significant clogging was observed on the columns that were treated by the brine containing both indigenous microorganisms and dissolved oxygen. In particular, iodide-oxidizing bacteria were detected from the columns and original brine dominantly; therefore, it was assumed to have an important influence on the clogging. Iodine that was produced by iodide-oxidizing bacteria corroded iron in the sand under the presence of dissolved oxygen. Eluted Iron formed ferric hydroxide colloid in the brine and it caused the clogging of the pore spaces.
We also demonstrated that deoxidized brine inhibited the iodide-oxidizing bacteria from becoming dominant and the column from the clogging through the column experiments. From these results, we can suggest removing dissolved oxygen as the most feasible countermeasures for the clogging..
23. Yuichi Sugai, Kyuro Sasaki, Keigo Yoshimura, Toshinori Yukitake, Shigenori Muta, Pilot study on the construction of several temperature-controlled multi-purpose rooms in a disused tunnel, Tunnelling and Underground Space Technology (Elsevier), 10.1016/j.tust.2012.06.009, 32, 180-189, 2012.11, Throughout the world, schemes for putting to use abandoned underground spaces are being pursued. We describe 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 (5ºC), cool (13ºC), mild (21ºC), and warm (32ºC) 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.
The heat transfer analysis of this facility was carried out through the computational analysis using a computational model constructed in this study. Computational analysis showed that the heat insulation property of the tunnel wall was reinforced by prolonged operation and the cost of operating facility became lower with the operation time. In addition, we demonstrated the procedure to estimate the overall heat transmission coefficients of the tunnel wall which was a great help in the design of similar facilities in underground spaces.
The different rooms in the facility are expected to be used for manufacturing fermented foods and drinks depending on temperature and humidity requirements. Not only running costs but also initial costs are expected to be lower than those for surface facilities; for this reason, our system has been demonstrated to be economically viable as well as environment friendly..
24. Ryo Mori, Yuichi Sugai, Kyuro Sasaki, Kazuhiro Fujiwara, Takamichi Nakamura, Experimental and Numerical Studies on the Microbial Restoration of Natural Gas Deposits in Depleted Oil Reservoirs Storing CO2, Society of Petroleum Engineers (SPE) Asia Pacific Oil and Gas Conference and Exhibition, SPE-158875-MS, 2012.10, We investigated the microbial conversion of CO2 into CH4 in depleted oil reservoirs by the interaction between indigenous oil-degrading hydrogen-producing bacteria and indigenous hydrogenotrophic methanogens that have been found in oil reservoirs universally. In this study, we investigated the influence of crude oil, yeast extract, bicarbonate and CO2 on the growth and gas production of those bacteria through the incubation experiments of isolated strains under reservoir conditions. The yeast extract was estimated to be the most influential factor on the growth and gas production of oil-degrading hydrogen-producing bacteria. Methanogen was unaffected by the crude oil, the yeast extract and bicarbonate, however, both CO2 and H2 are assumed to be the influential factors on it because they are the energy sources of methanogen.
In addition, we also investigated their growth kinetics that were needed to construct a numerical simulator of the microbial conversion of CO2 into CH4 in depleted oil reservoirs. The specific growth rate of oil-degrading hydrogen-producing bacteria was increased as the yeast extract concentration increased while that of the methanogen was constant regardless of the yeast extract concentration. These results indicate that the growth of methanogens is unaffected by the yeast extract that is injected into reservoirs to stimulate the growth of ODHPB. The growth yield of HYH-8 and HYH-10 was 5.5x1010 cells/g-(yeast extract) and 3.5x1011 cells/g-(yeast extract) respectively..
25. Yuichi Sugai, Isty A. Purwasena, Kyuro Sasaki, Kazuhiro Fujiwara, Yoshiyuki Hattori, Komei Okatsu, Experimental studies on indigenous hydrocarbon-degrading and hydrogen-producing bacteria in an oilfield for microbial restoration of natural gas deposits with CO2 sequestration, Journal of Natural Gas Science and Engineering (Elsevier), 10.1016/j.jngse.2012.01.011, 5, 31-41, 2012.03, Sequestration of carbon dioxide (CO2) into depleted oil reservoirs may be a method of reducing CO2 emissions. We focus on microbial restoration of natural gas deposits with CO2 sequestration via in situ microbial conversion of CO2 into methane (CH4) by hydrogenotrophic methanogens (HM) that universally inhabit oil reservoirs. The means of supplying HM with H2 for their CH4 production is central to this process. This study considers the potential of this process by evaluating the H2 productivity of hydrocarbon-degrading and hydrogen-producing bacteria (HD–HPB) that inhabit oil reservoirs.
Reservoir brine was extracted from 10 producing wellheads in the Yabase Oilfield of Japan. Indigenous bacteria in the brine samples were incubated with sterile oil under anaerobic conditions with 10%-CO2 (N2 balanced) at 50 °C and 75 °C. Production of H2 and CH4 and consumption of CO2 were observed in almost all the brine at both temperature, especially, larger amount of gases were produced at 50 °C. Those gases production was significantly stimulated with the additional yeast extract, on the other hand, it became lower under high pressure condition.
Nutrient agar inoculated with raw brine was incubated under anaerobic conditions at 50 °C and 75 °C. Microbial single colonies formed in the nutrient agar media after 2 weeks were selected and inoculated into sterile brine including sterile oil. More than 20 isolates were isolated and incubated in the brine media and 14 strains were observed to produce H2 after 3 months incubation. The maximum rate of H2 production by HD–HPB was 0.38 NmL/L-medium/day.
These results suggest that in situ microbial conversion of sequestrated CO2 and H2 generated by HD–HPB into CH4 using HM can be expected in many oilfields universally. Moreover, the most capable HD–HPB isolated in this study can be injected into reservoirs to stimulate the restoration of natural gas deposits with CO2 sequestration..
26. Ryo Wakizono, Yuichi Sugai, Kyuro Sasaki, Yasunori Higuchi, Noriyuki Muraoka, Investigation of Indigenous Bacteria in Water-dissolved Natural Gas Fields for Preventing Microbial Clogging of Injection Wells, Society of Petroleum Engineers (SPE) Asia Pacific Oil and Gas Conference and Exhibition, SPE-145990-MS, 2011.09, The brine that has been produced from water-dissolved natural gas reservoirs should be returned into reservoirs after the resources have been extracted to prevent the subsidence. However, the re-injectivity of the brine declines gradually; therefore, re-injection wells should be maintained by backwashing treatments. Colloidal materials like biofilms can be observed in solid materials that have been produced by the backwashing from the re-injection wells.
Because the brine contains not only dissolved natural gas but also high levels of iodine, the iodine is also extracted from the brine chemically using sulfuric acid and oxidizing agent; therefore, re-injected brine contains sulfate and dissolved oxygen abundantly. These chemicals may stimulate the metabolites of microorganisms that have influences on the clogging; therefore, we considered the influences of these materials on microorganisms that may cause the clogging in this study.
Column experiments were carried out using sand and brine that were collected in the gas field. The columns that the brine including indigenous microorganisms, dissolved oxygen and sulfate was injected into were clogged significantly. Iodide-oxidizing bacteria, iron-oxidizing bacteria and sulfate-reducing bacteria were found specifically in clogged columns, suggesting these microorganisms had influences on the clogging. In particular, Iodide-oxidizing bacteria were also found in original brine; therefore, it was assumed to have an important influence on the clogging.
Iodide-oxidizing bacteria convert iodide into iodine that corrodes iron in the sand under the presence of dissolved oxygen. Iron (II) ion that has been eluted from the sand is oxidized to iron (III) ion by iron-oxidizing bacteria under the presence of dissolved oxygen. Iron (III) ion forms ferric hydroxide colloid in the brine and it causes the clogging of the porous media.
From these mechanisms of the clogging, we can suggest removing dissolved oxygen as the most feasible countermeasures for the clogging..
27. Ryo Mori, Yuichi Sugai, Kyuro Sasaki, Kazuhiro Fujiwara, Evaluation of the Potential of Microbial Restoration of Natural Gas Deposit with CO2 Sequestration by Investigating Indigenous Bacteria in a High CO2 Content Oilfield, Society of Petroleum Engineers (SPE) Asia Pacific Oil and Gas Conference and Exhibition, SPE-145898-MS, 2011.09, We investigated the in situ microbial conversion of CO2 into CH4 by oil-degrading and H2-producing bacteria and hydrogenotrophic methanogens. CO2 is injected into depleted oil reservoirs as a method of carbon capture and storage (CCS). The bacteria involved in CO2 conversions are affected by high CO2 conditions, which cause a reduction in the pH level of the reservoir brine. Therefore, we assessed the efficacy of this microbial conversion process under high partial CO2 pressure by investigating the microbial communities present in high/low CO2 content reservoirs, the pH reduction of brine under high partial pressure of CO2, and the production of H2 and CH4 by indigenous bacteria in high CO2 content reservoirs. Thermotoga sp. and Thermoanaerobacter sp., which have previously been shown to produce hydrogen from crude oil by Fujiwara et al.1), were found to be the dominant species in the high CO2 content reservoir. Moreover, Methanobacterium sp. and Methanothermobacter sp., which are well-known hydrogenotrophic methanogens, were also detected in the reservoir. These results indicate that the microorganisms needed for this microbial conversion process can inhabit reservoirs where CO2 has been injected for CCS.
The pH of brine with bicarbonate levels > 0.1 mol/L was found to be maintained at pH 7.0–8.0, which is a favorable pH for the growth of a variety of microorganisms. Neutral pH levels were maintained even under CO2 partial pressure as high as 5.0 MPa, suggesting that the microbial conversion process could easily be applied in reservoirs whose brine is abundant in bicarbonate.
Enrichment culture experiments in brine were carried out under high CO2 partial pressure (3.0 MPa) at 75°C. Production of both H2 and CH4 was detected in brine with pH buffering action, as well as in brine with significantly reduced pH levels due to high CO2 partial pressure. Therefore, the microbial conversion process may also be expected to occur in normal reservoirs with poor acid neutralizing capacity..
28. Isty A. Purwasena, Yuichi Sugai, Kyuro Sasaki, Estimation of the Potential of an Oil-Viscosity-Reducing Bacterium Petrotoga sp. Isolated from an Oil Field for MEOR, Society of Petroleum Engineers (SPE) Annual Technical Conference and Exhibition, SPE-137568-MS, 2010.09.
29. Isty Adhitya Purwasena, Yuichi Sugai, Kyuro Sasaki, Estimation of the Potential of an Oil-Viscosity-Reducing Bacteria, Petrotoga sp., Isolated from an Oilfield for MEOR, Proceedings of International Petroleum Technology Conference 2009 (IPTC2009), IPTC-13861-MS, 2009.12.
30. Yuichi Sugai, Toshiya Niimi, Kyuro Sasaki, Yoshiyuki Hattori, Sanae Kano, Tsukasa Mukaidani, Kazuhiro Fujiwara and Komei Okatsu, Screening of Oil-Degrading and Hydrogen-Producing Microorganisms for Microbial Conversion of CO2 into CH4 in Oil Reservoir, Proceedings of CIPC/SPE GTS 2008 Joint Conference, SPE-115009-MS, 2008.06.
31. Yuichi Sugai, Hong Chengxie, Tadashi Chida, Heiji Enomoto, Simulation Studies on the Mechanisms and Performances of MEOR using Polymer Producing Microorganism Clostridium sp. TU-15A, Proc. of Society of Petroleum Engineers (SPE) Asia Pacific Oil and Gas Conference and Exhibition, SPE-110173-MS, 2007.10.
32. Characteristics of Functional Wall Material Containing a Green Tuff, Yuichi SUGAI, Kyuro SASAKI, Shigeyuki TAKAHATA and Hideo NAKA, Transactions of the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, No.123, 2007.
33. Possibility of the Towada-Stone Dust for the Deodorizer and the Compost Accelerator, Journal of Japan Institute of Aggregate Technology, No.147, pp.153-161, 2005.
34. The Abilities of Hinai-Green Tuff to Adjust pH and Activate Microorganisms, SUGAI Yuichi, SASAKI Kyuro, MATSUBAYA Osamu, NAKA Hideo and TANAKA Fujio, Journal of the Mining and Materials Processing Institute of Japan, Vol.121, No.10 (20051125) pp. 513-520 .
35. Laboratory Investigation on Profile Modification of Oil Reservoir Fluids by Water-insoluble Polymer Producing Microorganism CJF-002, SUGAI Yuichi, KISHITA Atsushi, YUMOTO Tetsuya, ENOMOTO Heiji, HONG Chengxie, FUJIWARA Kazuhiro and ONO Kenji, Journal of the Japanese Association for Petroleum Technology, Vol.70, No.4 (20050701) pp. 315-327 .
36. Numerical Experiments of MEOR with the microbe producing water-soluble polymer, SUGAI Yuichi, HONG Chengxie, CHIDA Tadashi and ENOMOTO Heiji, Journal of the Japanese Association for Petroleum Technology, Vol.69, No.5 (20040901) pp. 563-573 .
37. Y.SUGAI, J.FANGMING, H.ENOMOTO and T.MORIYA, Application of Membrane Separation Method to Concentrate Products on the Process Producing Environmentally Adaptable Deicer by means of Wet Oxidation of Organic Wastes, RESOURCES PROCESSING, Vol.51、No.3、148-157, 2004.09.
38. Simulation study on the performance and mechanism of MEOR with a water-soluble polymer producing microbe, SUGAI Yuichi, HONG Chengxie, CHIDA Tadashi and ENOMOTO Heiji, Journal of the Japanese Association for Petroleum Technology, Vol.69, No.4 (20040701) pp. 335-347 .
39. Numerical model for MEOR with a microbe producing water-soluble polymer, SUGAI Yuichi, HONG Chengxie, CHIDA Tadashi and ENOMOTO Heiji, Journal of the Japanese Association for Petroleum Technology, Vol.69, No.3 (20040501) pp. 262-271 .
40. Laboratory investigation on oil recovery with a Water-Soluble Polymer producing microorganism TU-15A, SUGAI Yuichi, HONG Chengxie, CHIDA Tadashi, ENOMOTO Heiji and YAZAWA Nintoku, Journal of the Japanese Association for Petroleum Technology, Vol.67, No.5 (20020901) pp. 491-500
.
41. Screening of water-soluble polymer producing microorganisms for MEOR, SUGAI Yuichi, HONG Chengxie, IKEDA Shuichiro, CHIDA Tadashi, ENOMOTO Heiji and YAZAWA Nintoku, Journal of the Japanese Association for Petroleum Technology, Vol.67, No.3 (20020501) pp. 277-286.
42. Yuichi Sugai, Atsushi Kishita, Hong Chengxie, Heiji Enomoto, Tadashi Chida, S.C.ZHOU, Laboratory Investigation of Polymer Producer TU-15A for MEOR Field Tests, Proc. of Society of Petroleum Engineers (SPE) Asia Pacific Oil and Gas Conference and Exhibition, SPE-54381-MS, 1999.04.
Works, Software and Database
1. .
Presentations
1. San Yee Khaing, Yuichi Sugai, Kyuro Sasaki, Novel Hydrometallurgical Method for Gold Leaching from Ore Using Iodide-Oxidising Bacteria, International Symposium on Earth Science and Technology 2018, 2018.11.
2. Jumpei Mikumo, Yuichi Sugai, Kyuro Sasaki, Investigation of a novel enhanced oil recovery technique using yeast residue, International Symposium on Earth Science and Technology 2018, 2018.11.
3. Nao Miyazaki, Yuichi Sugai, Kyuro Sasaki, Yoshifumi Okamoto, Chencan Ouyang, Dual role of citric acid as a binding inhibitor of anionic surfactant with bivalent cations and co-surfactant on bio-surfactant EOR, Abu Dhabi International Petroleum Exhibition and Conference 2018, 2018.11.
4. Masaki Uematsu, Yuichi Sugai, Kyuro Sasaki, Ronald Nguele, Investigation of the potential of polyvinyl alcohol as an inhibitor of spontaneous combustion of low rank coal, 7th World Conference on Applied Sciences, Engineering & Management, 2018.10.
5. Vo Thanh Hung, Yuichi Sugai, Kyuro Sasaki, An Object-Based Modeling and Simulation of CO2 Plume Dynamic in Saline Formation in Nam Vang Field, Cuu Long Basin, Vietnam, The 24th Formation Evaluation Symposium of Japan, 2018.10.
6. Yuichi Sugai, Challenges to Advance Microbial EOR Technique to a Practical Technique, Rundown Seminar International on "Maximizing More Barrels in Brownfield Rejunevation Through Enhanced Oil Recovery", 2018.08.
7. Masaki Uematsu, Yuichi Sugai, Kyuro Sasaki, The Developing Equipment for Evaluation to Coal Spontaneous Combustion
, Mining in Asia International Symposium, 2018.07.
8. San Yee Khaing, Yuichi Sugai, Kyuro Sasaki, Isolation and Culturing of Iodide-Oxidising Bacteria(IOB) from Brine, Mining in Asia International Symposium, 2018.07.
9. Eric Owusu Ansah, Yuichi Sugai, Kyuro Sasaki, Numerical Simulation of an Oil Viscosity Reduction Microbe for Enhanced Oil Recovery, 80th EAGE Conference & Exhibition 2018, 2018.06.
10. Evan Rosyadi Ogara, Yuichi Sugai, Kyuro Sasaki, Ferian Anggara, The Effect of Coal Characteristics on Adsorption and Desorption Gas at Indonesia Low Rank Coal, International Symposium on Earth Science and Technology 2017, 2017.12.
11. Gen Murakami,Yuichi Sugai,Kyuro Sasaki, Preliminary Study on In-situ Realtime Quantitation of Target Bacteria on the Principle of Flow Cytometry, 22th International Biohydrometallurgy Symposium, 2017.09.
12. Jumpei Tamai,Yuichi Sugai,Kyuro Sasaki, Measurement of the IFT between Oil and Water in which CO2 is dissolved, 6th World Conference on Applied Sciences, Engineering & Technology, 2017.08.
13. Noritaka Shimatani,Yuichi Sugai,Kyuro Sasaki, Basic Research of Enhanced Coalbed Methane Recovery by Injecting Air, 6th World Conference on Applied Sciences, Engineering & Technology, 2017.08.
14. Minoru Saito, Yuichi Sugai, Kyuro Sasaki, Yoshifumi Okamoto, Chencan Ouyang, Experimental and Numerical Studies on EOR Using a Biosurfactant, The Abu Dhabi International Petroleum Exhibition & Conference 2016, 2016.11.
15. エバン ロシャディ オガラ, 菅井裕一, フェリアン アンガラ, 佐々木 久郎, 石炭へのCO2およびCH4の吸脱着の測定, 資源・素材2016(盛岡), 2016.09.
16. Yuichi Sugai, Challenges to Advance Microbial Enhanced Oil Recovery Technique to a Practical Technique, ASEAN MICROBIAL BIOTECHNOLOGY CONFERENCE 2016, 2016.08.
17. Yuichi Sugai, Keita Komatsu, Kyuro Sasaki, Estimation of IFT Reduction by a Biomass Material and Potential of Its Utilization for EOR, SPE Asia Pacific Oil and Gas Conference and Exhibition, 2015.10, Surfactant injection is one of the most effective EOR techniques. Chemical surfactants however pose a few problems such as their high cost and low-degradability. We study on the utilization of biomass such as agricultural fertilizer mainly comprising the residue of squeezed beer yeast for EOR as an alternative of chemical surfactants because crude oil can be completely miscible with the fertilizer solution. The fertilizer can be stably supplied at a low cost because it is a waste of beer brewing industry and is only used for an animal feed additive so far. Its retail price is approximately 1 USD/kg in Japan.
We semi-quantitatively estimated the interfacial tension (IFT) between the fertilizer solution and crude oil by the oil displacement test. Concentration of the fertilizer was varied between 10 to 50 g/L. The fertilizer solution to which sodium chloride was added at a concentration of 10 to 40 g/L was hydrothermally treated at 60, 80, 100 or 120 ºC for 10, 20, 30, 45 or 60 minutes respectively before the tests. The fertilizer solution to which crude oil was added at a ratio of 1 % was also hydrothermally treated at 120 ºC for 20 minutes. Solution of surfactin which was a commercial biosurfactant was used as a standard of the IFT.
The IFT was reduced with the decrease in salinity and increase in concentration of the fertilizer and temperature of the hydrothermal treatment. Time of the hydrothermal treatment was preferably 30 minutes or less for the IFT reduction. The capability of 50 g/L of fertilizer solution to reduce the IFT was almost same as the capability of 0.2 g/L of the surfactin solution. Because the fertilizer solution comes into contact with residual oil under high temperature in oil reservoir, IFT between the solution and crude oil can be expected to be reduced in-situ.
Core flooding experiments were carried out by injecting the fertilizer solution after the water flooding as the primary oil recovery. 1.2 % of original oil in place was additionally recovered by injecting 50 g/L of the fertilizer solution after the water flooding.
The fertilizer should be biodegradable because it is a microbially-derived substance. In addition, because the IFT reduction was observed after the hydrothermal treatment of the fertilizer solution, the fertilizer should be effective even in the reservoir whose temperature is high such as 120 ºC at which chemical surfactants may be deactivated. From those results, the injection of the fertilizer solution can be a promising EOR which has both high cost performance, low environmental load and high versatility..
18. Yuichi Sugai, Keita Komatsu, Kyuro Sasaki, Kristian Mogensen, Martin Vad Bennetzen, Microbial-Induced Oil Viscosity Reduction by Selective Degradation of Long-Chain Alkanes, Abu Dhabi International Petroleum Exhibition and Conference 2014, 2014.11, Application of a thermophilic anaerobic bacterium which degrades long-chain alkanes of crude oil preferentially and induces oil viscosity reduction to MEOR in our target oilfield was evaluated in this study. Although the salinity of formation-water in our target reservoir is approximately 10 % which is considerably higher than the optimum salinity for the bacterium, the bacterium can grow well and induce oil viscosity reduction in the formation-water which was diluted with sea-water whose salinity was approximately 4 % and contained yeast extract as a nitrogen source. Oil viscosity was reduced to 70 percent of its original viscosity after two-week incubation of the bacterium in the culture medium consisting of sea-water supplemented with 1.0 g/L of yeast extract.
The performance of MEOR using this bacterium was evaluated by numerical simulation using two dimensional oil-water two-phase flow model. This model consists of 6 compositions: degraded oil, undegraded oil, brine, bacterium, sodium chloride and yeast extract. Undegraded oil and yeast extract are carbon source and nitrogen source for the bacterial growth respectively. Growth rate of the bacterium is calculated by Monod equation depending on the variables of the concentration of yeast extract and sodium chloride. Conversion of undegraded oil into degraded oil is depended on the proliferation of the bacterium. Growth of the bacterium is stopped by deficiency of either yeast extract or undegraded oil. Oil viscosity is reduced as the percentage of degraded oil in oil phase increases. Residual oil saturation is improved by oil viscosity reduction and enhancement of oil recovery can be obtained.
According to the numerical experiments, growth of the bacterium and oil viscosity reduction were found only around the injection well because the bacterium consumed whole yeast extract around there. Recovery factor therefore can be increased by increase of injection volume of yeast extract. As a result, enhancement of oil recovery reached to 5 % by 1.0 pore volume injection of sea-water containing the bacterium and 1.0 g/L of yeast extract. 100 bbl of oil was recovered additionally by using 1.0 tons of yeast extract in that case..
19. Yuichi Sugai, Yukihiro Owaki, Kyuro Sasaki, Fuminori Kaneko, Takuma Sakai, Numerical Prediction of Reservoir Souring Based on the Growth Kinetics of Sulfate-reducing Bacteria Indigenous to an Oilfield, SPE International Oilfield Corrosion Conference and Exhibition, 2014.05.
20. Yuichi Sugai, Ryo Mori, Kyuro Sasaki, Kazuhiro Fujiwara, Estimation of the Potential of Microbial Restoration of Natural Gas Deposit with CO2 Sequestration, International Symposium on Earth Science and Technology 2012, 2012.09.
21. Screening of Autotrophic Microorganisms and Oil-degrading Microorganisms for Microbial EOR.
22. Screening of oil-degrading and hydrogen-producing microorganisms for microbial conversion of CO2 into CH4 in oil reservoir.
23. Measurement of solvent gas solubility into core samples including oil using PVT analysis equipment.
24. Screening of Effective Thermophilic Microorganisms for Microbial Enhanced Oil Recovery.
25. Simulation Studies on the Mechanisms and Performances of MEOR using Polymer Producing Microorganism Clostridium sp. TU-15A.
26. Screening of the thermophilic bacteria that is helpful to popularize Microbial Enhanced Oil Recovery, Yuichi SUGAI, Machiko OKA and Kyuro SASAKI, Japan Petroleum Institute, November 2006.
27. Estimation of the effect of the microbial material using Hinai-Green tuff as a microbial carrier, Yuichi SUGAI, Ryohei YAYA, Kyuro SASAKI, Shigeyuki TAKAHATA and Hideo NAKA, Mining and Materials Processing Institute of Japan, March 2006.
28. EFFECTS OF A GREEN TUFF ON ACTIVATING MICROORGANISMS, Yuichi SUGAI and Kyuro SASAKI, 3rd International Workshop on Earth Science and Technology, December 2005.
29. Measurement of enviromental parameters in a poultry farm applied Hinai-Green tuff, Yuichi SUGAI, Kyuro SASAKI, Shigeyuki TAKAHATA and Hideo NAKA, Mining and Materials Processing Institute of Japan, September 2006.
30. Development of a bio-fartilizer made by an effective microorganism and Hinai-Green tuff, Yuichi SUGAI, Kyuro SASAKI, Shigeyuki TAKAHATA, Hideo NAKA and Fujio TANAKA, Mining and Materials Processing Institute of Japan, March 2006.
31. Introduction of Enhanced Oil Recovery Technique by using Microorganisms.
32. Characteristics of TOWADA stone and development of its utilization, Yuichi SUGAI, Kyuro SASAKI, Hideo NAKA and Fujio TANAKA, Mining and Materials Processing Institute of Japan, September 2004.
33. Development of the utilization of the rock dust of TOWADA-stone, Yuichi SUGAI and Kyuro SASAKI, The Resources Processing Society of Japan, June 2004.
34. Estimation of the ability of water-insoulble producing microorganism CJF-002 for the profile modification using network models., Yuichi SUGAI, Tetsuya YUMOTO, Atsushi KISHITA, Heiji ENOMOTO and Keiji NAGASE, Japanese Association for Petroleum Technology, May 2002.
Membership in Academic Society
  • Society of Petroleum Engineers, SPE
  • Mining and Materials Processing Institute of Japan
  • The Resources Processing Society of Japan
  • The Japan Petroleum Institute
  • Journal of the Japanese Association for Petroleum Technology