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List of Papers
Toshiaki Tanaka Last modified date：2024.04.25

Assistant Professor / Exploration Geophysics / Department of Earth Resources Engineering / Faculty of Engineering


Papers
1. Mel Anthony A. Casulla, Hideki MIZUNAGA, Toshiaki TANAKA, Imaging crustal features and Moho depths through enhancements and inversion of gravity data from the Philippine island arc system, Progress in Earth and Planetary Science, 10.1186/s40645-022-00473-8, 2022.03.
2. Saeid Jalilinasrabady, Toshiaki Tanaka, Ryuichi Itoi, Hiroki Goto, Numerical simulation and production prediction assessment of Takigami geothermal reservoir, ENERGY, 10.1016/j.energy.2021.121503, 236, 2021.12.
3. Hao Chen, Hideki Mizunaga, Toshiaki Tanaka, Gang Wang, Maik Neukirch, Application of a new robust impedance estimator based on Hilbert-Huang transform for magnetotelluric method, Proceedings of International Symposium on Earth Science and Technology 2021, 253-256, 2021.11.
4. Kazuto Inoue, Hao Chen, Toshiaki Tanaka, Hideki Mizunaga, Example of application of a new MT time series processing method, Proceedings of International Symposium on Earth Science and Technology 2021, 372-374, 2021.11.
5. Chuichi Inoue, Mizunaga Hideki, Toshiaki Tanaka, A study on visualization of underground roots using electrical techniques, Proceedings of International Symposium on Earth Science and Technology 2021, 368-371, 2021.11.
6. Akira Ueda, Toshiaki Tanaka, Minoru Kusakabe, Takafumi Furukawa, Tamagawa hyper-acidic hot spring and phreatic eruptions at Mt. Akita-Yakeyama Volcano: Part 2. Secular variations of SO4/Cl ratios and their relationship to the phreatic eruptions, Journal of Volcanology and Geothermal Research, 10.1016/j.jvolgeores.2021.107242, 414, 1-11, 2021.06.
7. Casula Mel Anthony Asis, Hideki Mizunaga, Toshiaki Tanaka, Torres Aniano, Subsurface Characterization using Geophysical and Hydrochemical Data: An Application to Groundwater Resources Management in Pampanga, Philippines, Proc. of International Symposium on Earth Science and Technology 2020, 162-168, 2020.11.
8. Hao Chen, Hideki Mizunaga, Toshiaki Tanaka, Gang Wang, New strategy to calculate robust impedance using RMHHT estimator for continuous and discontinuous broadband magnetotelluric time-series data, Proc. of International Symposium on Earth Science and Technology 2020, 169-172, 2020.11.
9. Yushin Higashi, Toshiaki Tanaka, Hideki Mizunaga, An Experimental Study on Quad-Loop EM Method, Proc. of International Symposium on Earth Science and Technology 2020, 426-429, 2020.11.
10. Soichiro Hashimoto, Toshiaki Tanaka, Hideki Mizunaga, A New Technique of Resistivity Measurement for Drilling Cores, Proc. of International Symposium on Earth Science and Technology 2020, 436-439, 2020.11.
11. Abebayehu Andarge Mengiste, Hideki Mizunaga, Toshiaki Tanaka, 1-D and 2-D Inversions of Magnetotelluric Data in Butajira Geothermal Field, Ethiopia, Proc. of International Symposium on Earth Science and Technology 2020, 440-444, 2020.11.
12. Yosuke KIYOMOTO, Hideki MIZUNAGA, Toshiaki TANAKA, Development of Magnetotelluric 1-D Sparse Inversion, Proc. of International Symposium on Earth Science and Technology 2019, 2019.12.
13. Hao Chen, Hideki MIZUNAGA, Toshiaki TANAKA, The research on the application of Hilbert-Huang Transformation to time series magnetotelluric data, Proc. of International Symposium on Earth Science and Technology 2019, 2019.12.
14. Soichiro Hashimoto, Hideki MIZUNAGA, Toshiaki TANAKA, Resistivity measurement technique using capacitor electrodes, Proc. of International Symposium on Earth Science and Technology 2019, 2019.12.
15. Asuki AIKAWA, Toshiaki TANAKA, Saeid JALILINASRABADY, Ryuichi ITOI, The reproduction of temperature change in production area of Ogiri geothermal field, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
16. Keiji HIRASE, Toshiaki TANAKA, Saeid JALILINASRABADY, Ryuichi ITOI, Automatic Parameter Estimation in Geothermal Reservoir Numerical Simulation, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
17. Shinnosuke ISHIHARA, Toshiaki TANAKA, Hideki MIZUNAGA, Ryuichi ITOI, Junichi TAKAYAMA, Satoru HIGUCHI, Improvement of the numerical model considering Ogiri deep faults No.2 in the Ogiri geothermal field, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
18. Makoto TOYONAGA, Saeid JALILINASRABADY, Toshiaki TANAKA, Ryuichi ITOI, Tracer test simulation considering lower permeability area near injection well, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
19. Yosuke KIYOMOTO, Hideki MIZUNAGA, Toshiaki TANAKA, Archaeological Survey for Genko Borui using Ground Penetrating Radar, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
20. Gosuke Hoshino, Hideki Mizunaga, Toshiaki Tanaka, Development of a Simulator for 3-D Long-Offset TEM method, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
21. Hideaki EJIMA, Hideki MIZUNAGA, Toshiaki TANAKA, Detection and classification of anomalies in GPR B-scan data, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
22. Shokai IWAMOTO, Hideki MIZUNAGA, Toshiaki TANAKA, GPR Survey at Kuratsukasa Area in Dazaifu Histrical Site, Fukuoka Prefecture, Japan, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
23. Kazuki YAMADA, Hideki MIZUNAGA, Toshiaki TANAKA, Spectrum analysis of gamma ray data to extract spectrum peaks, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
24. Yusuke EGUSA, Hideki MIZUNAGA, Toshiaki TANAKA, 3-D Simulation of Square Array Resistivity Method Considering the Effects of Mixture of Soil-Cement, Proc. of International Symposium on Earth Science and Technology 2018, 2018.11.
25. Shunichi OKAMOTO, Toshiaki TANAKA, Hideki MIZUNAGA, Development of a Measurement Instrument Controlled by PSoC5LP for Fluid Flow Electromagnetic Method, Proc. of International Symposium on Earth Science and Technology 2017, 571-573, 2017.12.
26. Gosuke HOSHINO, Hideki MIZUNAGA, Toshiaki TANAKA, Development of a Ray Tracing Program for Seismic Refraction Method, Proc. of International Symposium on Earth Science and Technology 2017, 574-576, 2017.12.
27. Ryosuke NAGAWA, Hideki MIZUNAGA, Toshiaki TANAKA, Development of an Inversion Program of Marine TEM Using PSO, Proc. of International Symposium on Earth Science and Technology 2017, 577-579, 2017.12.
28. Syokai IWAMOTO, Hideki MIZUNAGA, Toshiaki TANAKA, GPR Survey at Kuratsukasa District in Dazaifu Historical Site, Fukuoka Prefecture, Japan, Proc. of International Symposium on Earth Science and Technology 2017, 580-582, 2017.12.
29. Hideaki EJIMA, Hideki MIZUNAGA, Toshiaki TANAKA, Recognition of Buried Objects of GPR Using CNN, Proc. of International Symposium on Earth Science and Technology 2017, 586-588, 2017.12.
30. Yusuke EGUSA, Hideki MIZUNAGA, Toshiaki TANAKA, Simulation of Square Array Resistivity Method to Detect Subsurface Layer Boundaries, Proc. of International Symposium on Earth Science and Technology 2017, 589-591, 2017.12.
31. Three-dimensional Visualization of the Inner Structure of Iwabaru-Futagozuka Kofun Using Resistivity Method.
32. Khasani, S. Jalilinasrabady, T. Tanaka, H. Fujii, R. Itoi, The study on transient behaviors of two-phase flow in a geothermal production well for a short period of continuous measurement, Experimental Thermal and Fluid Science, 84, 10-17, 2017.06.
33. Khasani, S. Jalilinasrabady, T. Tanaka, H. Fujii, R. Itoi, The study on transient behaviors of two-phase flow in a geothermal production well for a short period of continuous measurement, Experimental Thermal and Fluid Science, 84, 10-17, 2017.06.
34. Keisuke YAMAMURA, RYUICHI ITOI, Toshiaki Tanaka, Takaichi IWASAKI, Numerical Analysis of Transient Steam-Water Two-Phase Flow in Geothermal Production Wells with Multiple Feed Zones, Proc. of 42nd Workshop on Geothermal Reservoir Engineering, Stanford University, 2017.02.
35. Kenta KONDO, RYUICHI ITOI, Toshiaki Tanaka, Numerical Simulation of the Sumikawa Geothermal Reservoir, Japan, Using iTOUGH2, Proc. of 42nd Workshop on Geothermal Reservoir Engineering, Stanford University, 2017.02.
36. Junichi Takayama, Toshiaki Tanaka, Ryuichi Itoi, Evaluation of hydrological feature of reservoir in the Ogiri geothermal field by tracer test, Journal of the Geothermal Research Society of Japan, 10.11367/grsj.39.129, 39, 3, 129-140, 2017.01, We analyzed tracer tests in the Ogiri geothermal field, which was conducted in 2008 and 2011, respectively. The test results were analyzed with the multi-flowpath model, then interpreted together with hydrological features of the field determined from geological settings and geophysical surveys. The results indicate the presence of two flow path for reinjected water flowing to the production zone in the Ginyu fault. A part of the reinjected water flows into the main production zone of the Ginyu fault directly through this fault from the west. The water also flows the Ogiri deep faults zone located to the south of the Ginyu fault, then flows into the Ginyu fault from the east which takes longer time to reach the production zone..
37. Khasani, S. Jalilinasrabady, T. Tanaka, H. Fujii, Ryuichi Itoi, The study on transient behaviors of two-phase flow in a geothermal production well for a short period of continuous measurement, Experimental Thermal and Fluid Science, 10.1016/j.expthermflusci.2017.01.017, 84, 10-17, 2017.01, Deliverability of geothermal production wells is evaluated by measuring wellhead pressure versus mass flow rate at several wellhead pressures. Controlling a main valve of the well results in the changes in wellhead pressure and mass flow rate. However, duration required for these variables to stabilize depends on flowing behavior of steam-water two-phase fluid in the wellbore. Fluid stabilization seems to be an important parameter, mainly for short period of measurement. In addition, the manner of controlling valve operation whether it starts from the well in full-closed condition or in full-opened condition seems to affect this flow stabilization. Thus, the experiment was carried out for a production well 2H-21 at Hatchobaru geothermal field, Japan to verify these hypotheses. The measurement apparatus consisted of pressure sensors, water level sensor and a PC to store the measured data. The data were recorded every second for the pressures at upstream of the orifices, the pressure drops at the orifices, the pressures at the separators, and the water level at weir box. The degree of valve opening was changed three times during the measurement. Then, the duration of respective wellhead valve operation for controlling flow rate affecting the flow stabilization in wellbore was observed. It was found that quick valve operation caused longer period for stabilization and produced impulse response of flow rate soon after the valve operation stopped. The fluid flow required about 7 min to stabilize for closing valve operation whereas it needed longer than 20 min to reach the stable condition for opening valve operation. After changing the wellhead pressure, the steam flow rate stabilized quickly while the water flow rate showed a gradual change..
38. ADRIANTO, Ryuichi ITOI, Toshiaki Tanaka, Fractal Analysis of Pressure Transient Response in the Matsukawa Geothermal Field, Proc. of International Symposium on Earth Science and Technology 2016, 2016.12.
39. Shunichi OKAMOTO, Toshiaki Tanaka, Ryuichi ITOI, A Stabilization Technique for Geothermal Reservoir Simulation by TOUGH2 by Way of Coarse Numerical Models, Proc. of International Symposium on Earth Science and Technology 2016, 2016.12.
40. Kohei OTSUKA, Ryuichi ITOI, Toshiaki Tanaka, Yuji Ohya, Saeid JALILINASRABADY, Numerical Modeling of Solar Chimney Power Generation System Using Geothermal Hot Water as a Heat Source, Proc. of International Symposium on Earth Science and Technology 2016, 2016.12.
41. Kenta KONDO, Ryuichi ITOI, Toshiaki Tanaka, Takaichi IWASAKI, Natural State Modeling of Geothermal Reservoir in Sumikawa, Akita, Japan, Proc. of International Symposium on Earth Science and Technology 2016, 2016.12.
42. Takahiro YOSHIKAWA, Ryuichi ITOI, Toshiaki Tanaka, Dissolution Experiments and Simulation on Silica Scale Removal in Geothermal Reinjection Wellbore, Proc. of International Symposium on Earth Science and Technology 2016, 2016.12.
43. Shogo HAMADA, Hideki MIZUNAGA, Toshiaki Tanaka, A Study on Identification of Signal and Noise in Fluid Flow Electromagnetic Method, Proc. of International Symposium on Earth Science and Technology 2016, 2016.12.
44. Keisuke IKEDA, Hideki MIZUNAGA, Toshiaki Tanaka, GPR Survey at Onigaura Tunnel Tombs and 2-D Simulation, Proc. of International Symposium on Earth Science and Technology 2016, 2016.12.
45. Takahiro Yoshikawa, RYUICHI ITOI, Toshiaki Tanaka, DISSOLUTION EXPERIMENTS OF SILICA SCALE AND DERIVATION OF DISSOLUTION KINETICS, Proc. 38th New Zealand Geothermal Workshop 2016, 2016.11.
46. Keisuke Yamamura, RYUICHI ITOI, Toshiaki Tanaka, Takaichi Iwasaki, NUMERICAL MODEL OF TRANSIENT STEAM-WATER TWO-PHASE FLOW IN GEOTHERMAL PRODUCTION WELLS, Proc. 38th New Zealand Geothermal Workshop 2016, 2016.11.
47. Kohei OTSUKA, RYUICHI ITOI, Toshiaki Tanaka, Yuji Ohya, Saeid JALILINASRABADY, STUDY ON A SOLAR CHIMNEY POWER GENERATION SYSTEM USING GEOTHERMAL HOT WATER AS A HEAT SOURCE, Proc. 38th New Zealand Geothermal Workshop 2016, 2016.11.
48. Shogo HAMADA, Hideki Mizunaga, Toshiaki Tanaka, Research about Measurement of Marine MT Probe's Posture, Proc. International Symposium on Earth Science and Technology 2015, 2015.12.
49. Toshihiro NAKAMURA, Toshiaki Tanaka, RYUICHI ITOI, Masato WATANABE, Daisuke FUKUDA, Kazuto MATSUMOTO, Estimation of Hydrological Structure in the Kakkonda Geothermal Field using Tracer Test Results, Proc. International Symposium on Earth Science and Technology 2015, 2015.12.
50. Kohei OTSUKA, RYUICHI ITOI, Toshiaki Tanaka, Improvement in Solar Chimney Power Generation by Using Hot Water as a Heat Source, Proc. International Symposium on Earth Science and Technology 2015, 2015.12.
51. Adrianto, RYUICHI ITOI, Toshiaki Tanaka, Modeling of alcohol tracer test in vapor-dominated geothermal reservoir, Proc. 37th New Zealand Geothermal Workshop 2015, 2015.11.
52. Toshihiro NAKAMURA, Toshiaki Tanaka, RYUICHI ITOI, Tomohiro YAMASHITA, Characteristics of Analysis Results of Tracer Responses through a Vertical Two-Dimensional Porous Medium using Multi Flow Path Model, Proc. 8th International Conference On Geological and Geo-Resources Engineering & 7th Mineral Symposium, 2015.09.
53. Tomohiro YAMASHITA, RYUICHI ITOI, Toshiaki Tanaka, Effects of Feed Point Configuration of Wells on Tracer Material Movement in Vertical Two Dimensional Porous Media, Proc. World Geothermal Congress 2015, 2015.04.
54. Shunichi HIRAYAMA, RYUICHI ITOI, Toshiaki Tanaka, Junichi TAKAYAMA, Reservoir Simulation for Reinjected Water Return in Produced Fluid of Wells at Ogiri Geothermal Field, Japan, Proc. World Geothermal Congress 2015, 2015.04.
55. Toshiaki Tanaka, Hideki Mizunaga, Development of Measuring Instruments for Fluid Flow Electromagnetic Method to Monitor Geothermal Fluid Flow, Proc. World Geothermal Congress 2015, 2015.04.
56. Hideki Mizunaga, Toshiaki Tanaka, Three-dimensional Inversion of Fluid Flow Electromagnetic Method to Visualize Geothermal Fluid Flow, Proc. World Geothermal Congress 2015, 2015.04.
57. Masahiro TAKAKI, RYUICHI ITOI, Toshiaki Tanaka, Laboratory experiment of tracer test in the two-dimensional heterogeneous porous medium, Proc. Stanford Geothermal Workshop 2015, 2015.01.
58. Christi Fina LINGKAN, RYUICHI ITOI, Toshiaki Tanaka, Jatmiko Prio ATMOJO, Characterization of Fluid Flow System between Injection and Production Wells by Tritium Tracer Test Analysis, Proc. Stanford Geothermal Workshop 2015, 2015.01.
59. Yohei Tateishi, RYUICHI ITOI, Toshiaki Tanaka, Junichi TAKAYAMA, Development of the Natural-State Model of the Geothermal Reservoir at Ogiri, JAPAN using iTOUGH2, Proc. Stanford Geothermal Workshop 2015, 2015.01.
60. Experimental study on reinjected fluid flow in reservoir using vertical two-dimensional porous medium.
61. Kenta Kuma, Hideki Mizunaga, Toshiaki Tanaka, Three-dimensional Modeling and Inversion of Fluid Flow Electromagnetic Method, Proc. International Symposium on Earth Science and Technology 2014, 2014.12.
62. Yohei Tateishi, RYUICHI ITOI, Toshiaki Tanaka, Natural-State Simulation of Geothermal Reservoir at Ogiri, Japan, Using a Numerical Model Incorporated with Stratigraphic Information, Proc. International Symposium on Earth Science and Technology 2014, 2014.12.
63. Yohei Tateishi, RYUICHI ITOI, Toshiaki Tanaka, Junichi TAKAYAMA, Numerical simulation of evolution of steam-water two-phase zone in a fractured geothermal reservoir by considering capillary pressure effects, Proc. 36th New Zealand Geothermal Workshop 2014, 2014.11.
64. RYUICHI ITOI, Haruhiro INAGAKI, Toshiaki Tanaka, Takaichi IWASAKI, EFFECTS OF LOW TEMPERATURE WATER INFLOW INTO WELLBORE AT SHALLOW FEEDZONE OF PRODUCTION WELL ON STEAM-WATER TWO-PHASE FLOW IN WELL, Proc. 36th New Zealand Geothermal Workshop 2014, 2014.11.
65. Kenta Kuma, Hideki Mizunaga, Toshiaki Tanaka, Three-dimensional Numerical Simulation of Fluid Flow Electromagnetic Method for Geothermal Fluid, Proc. Grand Renewable Energy 2014 International Conference and Exhibition, 2014.07.
66. Shota Kukita, Hideki Mizunaga, Toshiaki Tanaka, 3-D Forward Modeling of Airborne TEM Method for Wide Geothermal Area, Proc. Grand Renewable Energy 2014 International Conference and Exhibition, 2014.07.
67. Masahiro TAKAKI, RYUICHI ITOI, Toshiaki Tanaka, Takumi MARUO, Laboratory experiment of tracer test using two kinds of dyes in the vertical two-dimensional porous media, Proc. Grand Renewable Energy 2014 International Conference and Exhibition, 2014.07.
68. Toshiaki Tanaka, Hideki Mizunaga, DEVELOPMENT OF MEASUREMENT SYSTEM FOR FLUID FLOW ELECTROMAGNETIC METHOD TO EVALUATE GEOTHERMAL FLUID FLOW BEHAVIOR, Proc. Grand Renewable Energy 2014 International Conference and Exhibition, 2014.07.
69. Takeru OKUZAWA, Toshiaki Tanaka, Hideki Mizunaga, Development of a Practical Measurement Equipment for Time-domain IP Method, Proc. International Symposium on Earth Science and Technology 2013, 2013.12.
70. Masahiro TAKAKI, Takumi MARUO, Toshiaki Tanaka, RYUICHI ITOI, Laboratory Experiment of Tracer Test in the Vertical Two-dimensional Porous Media Using Two Kinds of Tracers, Proc. International Symposium on Earth Science and Technology 2013, 2013.12.
71. Takumi MARUO, Masahiro TAKAKI, RYUICHI ITOI, Toshiaki Tanaka, Laboratory Experiment and Numerical Simulation of Tracer Test with Vertical Two-dimensional Porous Media, Proc. International Symposium on Earth Science and Technology 2013, 2013.12.
72. Takeshi HINO, RYUICHI ITOI, Toshiaki Tanaka, Agung PAMBUDI, Khasani, Effects of Production and Injection Rates on the Reservoir Performance of the Dieng Geothermal Field, Central Java, Indonesia, Proc. International Symposium on Earth Science and Technology 2013, 2013.12.
73. Yohei TATEISHI, RYUICHI ITOI, Toshiaki Tanaka, Naoto HIRAGA, Junichi TAKAYAMA, Estimation of Reservoir Parameters of the Ogiri Geothermal Field Using iTOUGH2, Proc. International Symposium on Earth Science and Technology 2013, 2013.12.
74. Yohei TATEISHI, RYUICHI ITOI, Toshiaki Tanaka, Naoto HIRAGA, Jyunichi TAKAYAMA, Numerical Simulation of Devolution and Evolution of Steam-Water Two-Phase Zone in a Fractured Geothermal Reservoir at Ogiri, Japan, Geothermal Resources Council Transactions , 37, 915-920, 2013.10.
75. Masahiro TAKAKI, RYUICHI ITOI, Toshiaki Tanaka, Takumi MARUO, Laboratory Experiment of Tracer Test in the Vertical Two-Dimensional Porous Media With Newly Developed Tracer Sensors, Geothermal Resources Council Transactions , 37, 337-340, 2013.10.
76. RYUICHI ITOI, Yasunari KATAYAMA, Toshiaki Tanaka, Naoto KUMGAI, Takaichi IWASAKI, Numerical Simulation of Instability of Geothermal Production Well, Geothermal Resources Council Transactions , 37, 837-842, 2013.10.
77. Takeshi HINO, RYUICHI ITOI, Toshiaki Tanaka, Nugroho Agung PAMBUDI, Khasani, Natural state model of Dieng geothermal field, Central Java, Indonesia, Geothermal Resources Council Transactions , 37, 831-836, 2013.10.
78. Katayama, Yasunari, ITOI RYUICHI, Tanaka Toshiaki, Numerical Simulation of Transient Two-Phase Flow in Geothermal Production Well with Multi-Feed Zones, Proceedings of the 2nd ITB Geothermal Workshop, 36, 1299-1304, 2013.03.
79. Y. Ebihara, Toshiaki Tanaka, Fundamental properties of substorm time energetic electrons in the inner magnetosphere, Journal of Geophysical Research, 10.1002/jgra.50115, 118, 4, 1589-1603, 2013.01, We studied fundamental properties of spatial-temporal evolution of energetic electrons trapped in the inner magnetosphere (L ≤ 7.4) during an isolated substorm by using a four-dimensional drift kinetic simulation under the time-dependent electric and magnetic fields provided by a global magnetohydrodynamics (MHD) simulation. When the interplanetary magnetic field turns southward, both the potential and induction electric fields start to increase in the inner magnetosphere, resulting in a gradual injection of low-energy electrons (≤51.9 keV) and deceleration of high-energy electrons (≥114 keV). The deceleration of high-energy electrons results in a decrease in the phase space density of the high-energy electrons during the growth phase. After a while, an abrupt transition of phase state (a substorm onset) occurs in the magnetosphere, which triggers abrupt changes in the magnetosphere and ionosphere. The AL index decreases rapidly, and magnetic field lines become dipole-like. The dipolarization does not proceed smoothly in the inner magnetosphere because of significant force imbalance between the J × B force and the grad P force. As a consequence, the electric field oscillates with a period of 2-3 min, resulting in multiple injections of the low-energy electrons. The low- and high-energy electrons are accelerated under the strong influence of the drift betatron and gyro betatron, so that the acceleration process is essentially nonlinear. Our simulation results suggest that the force-induced processes play an essential role in the substorm-associated redistribution of energetic particles in the inner magnetosphere. Key Points Two types of substorm-electric fields are identified in the inner magnetosphere.Electric field oscillation is generated by force imbalance near substorm onsetRedistribution of energetic electrons comes from force imbalance and ionosphere.
80. Riogilang, Hendra, ITOI RYUICHI, Tanaka Toshiaki, Jalilinasrabady, Saeid, Natural State Model of the Kotamobagu Geothermal System, North Sulawesi, Indonesia, Geothermal Resources Council Transactions, 36, 1299-1304, 2012.10.
81. Okuzawa Takeru, Toshiaki Tanaka, Hideki Mizunaga, Development of 2.5-D Modeling Program for Time-Domain IP Method, Proc. KSEG International Sympusium on "Geophysics for Discovery and Exploration", 2012.09.
82. Okumoto Ryosuke, Hideki Mizunaga, Toshiaki Tanaka, Development of 2.5-D Modeling Program for Time-Domain IP Method, Proc. KSEG International Sympusium on "Geophysics for Discovery and Exploration", 2012.09.
83. Takumi MARUO, RYUICHI ITOI, Toshiaki Tanaka, Hideto OISHI, Laboratory experiment of tracer test with vertical two-dimensional porous media, Proc. International Symposium on Earth Science and Technology 2012, 2012.09.
84. Yusuke SHIMOTOKU, Tanaka Toshiaki, ITOI RYUICHI, PERFORMANCE IMPROVEMENT OF TOUGH2 SIMULATION WITH GRAPHICS PROCESSING UNIT, PROCEEDINGS, TOUGH Symposium 2012, 2012.09.
85. Saeid Jalilinasrabady, ITOI RYUICHI, Hiroki Gotoh, Tanaka Toshiaki, NUMERICAL RESERVOIR MODEL OF THE TAKIGAMI GEOTHERMAL FIELD, OITA, JAPAN, PROCEEDINGS, TOUGH Symposium 2012, 2012.09.
86. Okumoto Ryosuke, Hideki Mizunaga, Toshiaki Tanaka, Development of 2.5-D Modeling Program for Time-Domain IP Method, Proc. KSEG International Sympusium on "Geophysics for Discovery and Exploration", 2012.09.
87. S. Fujita, H. Yamagishi, Ken T. Murata, M. Den, Toshiaki Tanaka, A numerical simulation of a negative solar wind impulse Revisited, Journal of Geophysical Research: Space Physics, 10.1029/2012JA017526, 117, 9, 2012.01, [1] Response of the magnetosphere-ionosphere system to a negative impulse of the solar wind dynamic pressure (the negative SI) is studied again with foci of the following three points; multiple convection oscillations, mirror-image relationship between the negative and positive SIs, and appearance of the overshielding potential. When the negative impulse impinges on the magnetopause, the Region 1 (R1)-type field-aligned current (FAC) and R2-type FAC appears alternatively in the dayside polar ionosphere (∼70°, ∼10 hLT and 14 hLT). These ionospheric current systems shift nightward and poleward. This alternative appearance of FACs invokes positive and negative ionospheric potential patterns switching alternatively. It is revealed that the negative SI is accompanied with multiple convection oscillations repeating more than the positive SI. We also notice that the magnetospheric current system producing the preliminary impulse (PI) of the intensive negative SI is a mirror-image of that of the positive SI. The multiple convection oscillations and the mirror-image relationship were not discussed by Fujita et al. (2004) who studied a moderate-amplitude negative SI. In addition, the R2-type FACs induced by the negative and positive SIs tend to yield the overshielding electric potential in the ionosphere. The shielding potential invoked by the SIs has shorter duration than that for the northward turn of the interplanetary magnetic field. The duration is longer for the negative SI than for the positive SI..
88. Seiji YAMASHITA, Ryuichi ITOI and Toshiaki TANAKA, A Three Dimensional Numerical Modeling of the Ogiri Geothermal System using TOUGH2 and iTOUGH2, Proceedings of International Symposium on Earth Science and Technology 2011, 2011.12.
89. Moriaki IWASAKI, Ryuichi ITOI and Toshiaki TANAKA, Analysis of Tracer Flow in a Two-dimensional Porous Media, Proceedings of International Symposium on Earth Science and Technology 2011, 2011.12.
90. Ryuichi ITOI, Seiji YAMASHITA, Toshiaki TANAKA, Jyunichi TAKAYAMA, Numerical Simulation of Reinjected Water Return to Production Wells in Ogiri Geothermal Reservoir, Japan, Resources Council Transactions, 1437-1442, 2011.10.
91. Saeid JALILINASRABADY, 糸井龍一, Pall VALDIMARSSON, 藤井 光, 田中俊昭, Energy and Exergy Analysis of Sabalan Binary Geothermal Power Plant, 日本地熱学会誌, 33, 3, 113-121, 第33巻、第3号、pp.113-121, 2011.07.
92. S. Saita, A. Kadokura, N. Sato, S. Fujita, Toshiaki Tanaka, Y. Ebihara, S. Ohtani, G. Ueno, K. Murata, D. Matsuoka, A. Kitamoto, T. Higuchi, Displacement of conjugate points during a substorm in a global magnetohydrodynamic simulation, Journal of Geophysical Research, 10.1029/2010JA016155, 116, 6, 2011.01, We reproduce a magnetospheric reconfiguration under southward interplanetary magnetic field (IMF) conditions using numerical magnetohydrodynamic simulations. To investigate the relative displacements of the geomagnetic conjugate points, we trace both footprints of the geomagnetic field lines during the magnetospheric reconfiguration under positive and negative IMF By conditions. Several substormlike features, namely, the formation of a near-Earth neutral line, a fast earthward flow, and tailward releases of the plasmoid, occur about 1 h after a southward turning of the IMF. The surveyed field line traced from the near-Earth magnetotail was strongly distorted duskward in the north and south after the substorm onset for positive and negative IMF By, respectively. The maximum of the relative longitudinal displacement of both footprints is 4.5 and 5.5 h in magnetic local time for positive and negative IMF By, respectively. While observational studies have indicated that the IMF orientation is the main factor controlling the relative displacement of the conjugate points, the present simulation-based study with a constant IMF orientation shows for the first time that the combined effects of plasma pressure, magnetic field intensity, and the field-aligned current density distribution along the field line are likely to be major factors controlling the relative displacement of conjugate points..
93. Naoto KUMAGAI, Toshiaki TANAKA and Ryuichi ITOI, Analysis of Tracer Returns by Considering Geological Structure in the Sumikawa Geothermal Field, Northeast Japan, Proceedings of International Symposium on Earth Science and Technology 2010, 351-356, 2010.12.
94. Saeid JALILINASRABADY, Ryuichi ITOI, Hikari FUJII and Toshiaki TANAKA, Flash Cycle and ORC Geothermal Power Plant Optimization Combined with District Heating System, Proceedings of International Symposium on Earth Science and Technology 2010, 357-362, 2010.12.
95. Ryuichi Itoi, Yurie Kumamoto, Toshiaki Tanaka and Junichi Takayama, History Matching Simulation of the Ogiri Geothermal Field, Japan, Proceedings of World Geothermal Congress 2010, 2010.04.
96. Saeid Jalilinasrabady, Ryuichi Itoi, Hikari Fujii, Toshiaki Tanaka, Energy and Exergy Analysis of Sabalan Geothermal Power Plant, Iran, Proceedings of World Geothermal Congress 2010, 2010.04.
97. Saeid Jalilinasrabady, Ryuichi Itoi, Hikari Fujii, Toshiaki Tanaka, Cascade Uses of Geothermal Energy in Sabalan - Iran, Proceedings of World Geothermal Congress 2010, 2010.04.
98. Hideki Mizunaga and Toshiaki Tanaka, Imaging of Geothermal Fluid Flow by Using Fluid Flow Electromagnetic Method, Proceedings of World Geothermal Congress 2010, 2010.04.
99. Toshiaki Tanaka and Ryuichi Itoi, Development of Numerical Modeling Environment for TOUGH2 Simulator on the Basis of Graphical User Interface (GUI), Proceedings of World Geothermal Congress 2010, 2010.04.
100. Three-dimensional imaging of GPR data using F-K migration.
101. Archaeological prospecting of keyhole shaped mounded tombs at Ito campus of Kyushu University.
102. Yurie KUMAMOTO, Ryuichi ITOI, Toshiaki TANAKA and Junichi TAKAYAMA, Exploitation modeling and reservoir performance prediction for the Ogiri geothermal system in Japan, Proceedings of International Symposium on Earth Science and Technology 2009, 2009.12.
103. Saeid Jalilinasrabady, Ryuichi Itoi, Hikari Fujii and Toshiaki Tanaka, Comparison of Geothermal and Fuel-fired Heating Systems in Sabalan - IRAN, Proceedings of International Symposium on Earth Science and Technology 2009, 2009.12.
104. Shoichiro Hozumi, Ryuichi Itoi, Toshiaki Tanaka, Hiroki Gotoh, Development of numerical model of Takigami geothermal reservoir, Oita, Japan, incorporated with wellbore flow simulation, Proceedings of International Symposium on Earth Science and Technology 2009, 2009.12.
105. Aijiro Shigematsu, Toshiaki Tanaka and Hideki Mizunaga, Development of Small Measurering Equipment for Electromagnetic Method, Proceedings of International Symposium on Earth Science and Technology 2009, 427-429, 2009.12.
106. Saeid Jalilinasrabady, Ryuichi Itoi, Hikari Fujii and Toshiaki Tanaka, Optimization of the Sabalan geothermal power plant, Iran, using exergy concept, Proceedings of 31th New Zealand Geothermal Workshop, CD, 2009.11.
107. Yurie KUMAMOTO, Ryuichi ITOI, Toshiaki TANAKA and Junichi TAKAYAMA, History matching and prediction simulations of the Ogiri geothermal field, Kyushu, Japan, Proceedings of 31th New Zealand Geothermal Workshop, CD, 2009.11.
108. Jalilinasrabady, S., Itoi, R., Fujii, H. and Tanaka, T., Energy and exergy analysis of single flash geothermal power plant, Sabalan, Iran, Proceedings of 2nd International Symposium of Novel Carbon Resource Science, 37-46, 2009.03.
109. Kumamoto, Y., Itoi, R., Tanaka, T.; Tanaka, Toshiaki;, T. and Hazama, Y., Modeling and Numerical Analysis of the Two-phase Geothermal Reservoir at Ogiri, Kyushu, Japan, Proceedings of Thirty-Fourth Workshop on Geothermal Reservoir Engineering, Stanford University, 79-87, 2009.02.
110. Khasani, Tanaka, T.; Tanaka, Toshiaki;, T. and Itoi, R., Interpretation of Continuous Measurement of Steam and Water Flow Rates at a Production Well 2H-21, Hatchobaru Geothermal Field, Japan, 30th New Zealand Geothermal Workshop, 2008.10.
111. Younes Noorollahi, Ryuichi ITOI, Hikari Fujii, Toshiaki Tanaka, GIS Integration Model for Geothermal Exploration and Well Siting, Geothermics, vol.37, 107-131, 2008.04.
112. Younes Noorollahi, Ryuichi Itoi, Hikari Fujii, Toshiaki Tanaka, GIS integration model for geothermal exploration and well siting, Geothermics, 10.1016/j.geothermics.2007.12.001, 37, 2, 107-131, 2008.04, The work involved in identifying geothermal fields can be simplified by means of a Geographical Information System (GIS), a decision-making tool used to determine the spatial association between exploration and environmental thematic maps. This methodology has been applied to part of the Sabalan geothermal field in northwestern Iran, and to the siting of exploration wells. The datasets used in the analyses consist of geological, geochemical and geophysical information. Boolean and Index Overlay knowledge-driven models were developed for site selection; the findings from these two models correlated well with the exploration data modeling. The results of the Index Overlay model were combined with those of an environmental suitability analysis for final selection of well sites. The results of exploration and environmental data modeling were combined to select and prioritize the sites of three exploratory wells in the study area..
113. Yurie Kumamoto, Ryuichi Itoi, Toshiaki Tanaka and Yukio Hazama, DEVELOPMENT OF THE OPTIMUM NUMERICAL RESERVOIR MODEL OF THE OGIRI GEOTHERMAL FIELD, KYUSHU, JAPAN, USING ITOUGH2, Thirty-Third Workshop on Geothermal Reservoir Engineering, Stanford University, SGP-TR-185, SGP-TR-185, 2008.02.
114. Noorollahi YOUNES, Ryuichi ITOI and Toshiaki TANAKA, Well Testing and Reservoir Properties Analyzing in Sabalan Geothermal Field, Northwestern Iran, Proc. 5th International Symposium on Earth Science and Technology, 247-254, 2007.12.
115. Akira NAKATANI, Ryuichi ITOI, Toshiaki TANAKA, Hiroki GOTOH, and Shigetsugu FURUYA, Development of Numerical Model of Takigami Geothermal Reservoir, Kyushu, Japan, Using iTOUGH2 Simulator, Proc. of New Zealand Geothermal Workshop, 2007.11.
116. Porras, E.A., Tanaka, T.; Tanaka, Toshiaki;, T., Fujii, H. and Itoi, R., Numerical modeling of the Momotombo geothermal system, Nicaragua, Geothermics, 2007.09.
117. Noorollahi YOUNES, Ryuichi ITOI, Hikari FUJII and Toshiaki TANAKA, GIS Model for Geothermal Resources Exploration in Akita and Iwate Prefecture, Northern Japan, Computer and Geosciences, Vol.33, pp.1008-1021, 2007.08.
118. Enrique A. Porras, Toshiaki Tanaka, Hikari Fujii, Ryuichi Itoi, Numerical modeling of the Momotombo geothermal system, Nicaragua, Geothermics, 10.1016/j.geothermics.2007.04.004, 36, 4, 304-329, 36, 304-329, 2007.08, The Momotombo geothermal field, Nicaragua, has been under commercial production since 1983; presently it has an installed capacity of 77 MWe. A three-dimensional, porous-media numerical model of the system was developed and calibrated using the code iTOUGH2, and was utilized to study the response of the geothermal reservoir under different fluid production and injection scenarios. Satisfactory agreements were obtained between measured and computed discharge enthalpies and flow rates for most of the shallow wells. The model also qualitatively reproduced the pressure drawdowns measured in selected wells..
119. Younes Noorollahi, Ryuichi Itoi, Hikari Fujii, Toshiaki Tanaka, GIS model for geothermal resource exploration in Akita and Iwate prefectures, northern Japan, Computers and Geosciences, 10.1016/j.cageo.2006.11.006, 33, 8, 1008-1021, 2007.08, In this study, a Geographic Information System (GIS) is used as a decision-making tool to target potential regional-scale geothermal resources in the Akita and Iwate prefectures of northern Japan. The aims of the study are to determine the relationships between geothermal wells and geological, geochemical, and thermal data layers within the GIS and to use these relationships to identify promising areas for geothermal exploration. We calculated the distances from existing productive geothermal wells to Quaternary volcanic rocks, calderas and craters, faults, hot springs, fumaroles, and hydrothermal alteration zones. The dominant distances were then defined for each evidence layer. We used ArcMap to develop a GIS Model for Geothermal Resource Exploration (GM-GRE) consisting of geoprocessing tools and a modelbuilder. Areas of geothermal potential were defined and prioritized by assigning a weighted overlying selection query for geological, geochemical, and thermal data layers. The result shows that 97% of currently productive geothermal wells in Akita and Iwate prefectures are located within the first priority zone selected by the GM-GRE..
120. Enrique A. Porras, Toshiaki Tanaka, Hikari Fujii, Ryuichi Itoi, Numerical modeling of the Momotombo geothermal system, Nicaragua, Geothermics, 10.1016/j.geothermics.2007.04.004, 36, 4, 304-329, 2007.08, The Momotombo geothermal field, Nicaragua, has been under commercial production since 1983; presently it has an installed capacity of 77 MWe. A three-dimensional, porous-media numerical model of the system was developed and calibrated using the code iTOUGH2, and was utilized to study the response of the geothermal reservoir under different fluid production and injection scenarios. Satisfactory agreements were obtained between measured and computed discharge enthalpies and flow rates for most of the shallow wells. The model also qualitatively reproduced the pressure drawdowns measured in selected wells..
121. Development of a three-dimensional imaging program for remains.
122. Development of a three-dimensional imaging program for remains.
123. Younes NOOROLLAHI, Ryuichi ITOI, Hikari FUJII and Toshiaki TANAKA, Regional and Local Scale Geothermal Resources Exploration and Potential Site Selection Using GIS in Ardebil Province Northwestern Iran, Proc. 4th International Workshop on Earth Science and Technology, 407-421, 2006.12.
124. Younes NOOROLLAHI, Ryuichi ITOI, Hikari FUJII, Toshiaki TANAKA, GIS Model for Geothermal Resources Exploration (GM-GRE) in Sabalan Geothermal Area Northwestern Iran, Proc. 4th International Workshop on Earth Science and Technology, 407-421, 2006.12.
125. Ushijima, Keisuke, Mizunaga, Hideki, Tanaka, Toshiaki, Toshiaki, Mine and UXO Exploration by Electrical Resistivity Measurements, Proceedings of the SAGEEP2006, 1615-1623, 2006.03.
126. Mizunaga, Hideki, Tanaka, T.; Tanaka, Toshiaki;, Toshiaki, and Ushijima, Keisuke, Fluid-Flow Monitoring by a 4-D Geoelectrical Techniques, Proceedings of Symposium in the Application of Geophysics to Engineering and Environmental Problems, Proceedings of the SAGEEP2006, 1494-1504, 2006.03.
127. Mizunaga, Hideki, Tanaka, T.; Tanaka, Toshiaki;, Toshiaki, and Ushijima, Keisuke, 3D Imaging of Archaeological Tomb by Electrical Resistivity Techniques, Proceedings of the SAGEEP2006, 1374-1377, 2006.03.
128. Toshiaki Tanaka, Substorm onset caused by the two state transition of the magnetosphere, Multiscale Coupling of Sun-Earth Processes, 10.1016/B978-044451881-1/50016-2, 217-233, 2005.12, The substorm process is simulated by resistive magnetohydrodynamic (MHD) equations. Starting from a stationary solution under a northward interplanetary magnetic field (IMF) condition with non-zero IMF, By, changes in magnetospheric convection following the southward turning of the IMF are investigated. The simulation results first show the progress of plasma sheet thinning in the tail. This thinning is caused by the drain of closed flux from the near-earth plasma sheet coupled with the enhanced ionospheric convection. In this stage, the flux transported from the near-earth tail to the dayside cannot be replaced by the flux from the midtail because the reclosure process of open field lines in the midtail plasma sheet is still slow because of the control by the remnant of northward IMF. The substorm onset occurs as an abrupt shift of the pressure peak in the plasma sheet from -12 Re to -8 Re and an intrusion of convection flow into the inner magnetosphere. After the onset, the simulation results reproduce both the dipolarization in the near-earth tail and the formation of near-earth neutral line (NENL) at the midtail, together with plasma injection into the inner magnetosphere and an enhancement of the nightside field-aligned current (FAC). During the dipolarization process, the static magnetospheric force balance changes from the z-direction-dominated state to the x-direction-dominated state. Thus, the dipolarization is not a mere pile up of the flux ejected from the NENL. The pressure distribution in the near-earth plasma sheet changes so, as to self adjust the restored magnetic tension associated with the establishment of force balance in the x direction. The direct cause of the onset is the state (phase-space) transition of the convection system from a thinned state to a dipolarized state..
129. Enrique PORRAS, Toshiaki TANAKA, Hikari FUJII and Ryuichi ITOI, Numerical Modeling of the Momotombo Geothermal Reservoir, Nicaragua, Proc. World Geothermal Congress 2005, CD, 2005.04.
130. Patricia MOLINA, Toshiaki TANAKA, Ryuichi ITOI, Farell SIEGA and Manny OGENA, Analysis and interpretation of Naphthalene Disulfonate Tracer Tests at the Mahanagdong geothermal field, Philippines, Proc. World Geothermal Congress 2005, CD, 2005.04.
131. Enrique PORRAS, Ryuichi ITOI, Hikari FUJII and Tosiaki TANAKA, Predictions of reservoir performances for different scenarios at Momotombo Predictions of reservoir performances for different scenarios at Momotombo geothermal field, Nicaragua, Proc. 26th Annual PNOC-EDC Conference, 51-57, 2005.03.
132. Toshiaki Tanaka, Shinichi Koshi, Patricia Molina, Ryuichi Itoi, Tatsuya Kajiwara, Analysis of Tracer Test Performed in the Kakkonda Geothermal Field with Multi-flowpath Model, Journal of the Geothermal Research Society of Japan, 10.11367/grsj1979.27.293, 27, 4, 293-305, 2005.01, For analysis of the hydrological connectivity between production and reinjection wells in the Kakkonda geothermal field, tracer tests were performed in 2002. In the tracer test, two different types of tracer were injected at respective reinjection well-116 and 136, and tracer return was examined by repeated sampling of water at 26 production wells. The results were analyzed with the multi-flowpath model to evaluate the magnitude of hydrological connectivity among the wells used in the tracer test, and to understand the flow behavior of reinjected water. Satisfactory results were obtained with a two-flowpath model for most production wells. Comparison of fluid velocities in each flowpath and the directions between the main feed points of production and reinjection wells indicated a possibility that some production wells are hydrologicaly connected to each other through the same fracture system. Tracer return are divided into two groups on the basis of mean-arrival-time, and amount of reinjected water return to production zone is appreciable for those with longer arrival time..
133. Keisuke USHIJIMA, Hideki MIZUNAGA and Toshiaki TANAKA, Imaging of Keyhole Tomb, Electrical Prospecting, Proceedings of the Annual General Assembly and the 6th Special Symposium of Korean Society of Exploration Geophysicists, 3-7, 2004.06.
134. Bingrui LI, Kenichi UCHINO, Masahiro INOUE and Toshiaki TANAKA, Location of Spontaneous Combustion in a Coal Waste Pile by Self-Potential Method, Proceedings of the 5th International Symposium on Mining Science and Technology, 249-253, 2004.06.
135. Naoto Kumagai, Toshiaki Tanaka, Koji Kitao, Characterization of geothermal fluid flows at Sumikawa geothermal area, Japan, using two types of tracers and an improved multi-path model, Geothermics, 10.1016/j.geothermics.2003.08.010, 33, 3, 257-275, 2004.06, Potassium bromide (KBr) and potassium iodide (KI) tracers were individually injected into two reinjection wells at Sumikawa: KI with steam condensate into one well and KBr with separated waste water at high temperature (140 °C), into another well 1000 m away from the KI well. The tracer concentrations were then analyzed in all production wells for 16 months. The iodine tracer was first detected in two wells (wells S-4 and SB-1) within 1000 m of the injection well within 47 h and in other wells (with the exception of well SC-2) up to 1500 m away within 9 days after injection. Before background correction as mentioned below, most of the injected iodine tracer was recovered from the production wells within 6 months. The bromine tracer was also observed first in well S-4 within 5 days and in other wells within 1 month, except for well SC-2. These observations show that vapor condensate quickly returns into wells S-4 and SB-1 compared to geothermal fluids. These results are consistent with the previous calculations examined through a box model using chlorine concentrations and hydrogen isotope ratios of fluids from production wells. The results of the present tracer tests were examined using a multi-path model. First, the background concentrations of both tracers were recalculated because the total recovered amounts of I and Br exceed the amounts that were originally injected. The variations of the tracer concentrations were then fitted by setting two or three paths between the injection and production wells. Our calculations show that the recovered fractions of I and Br are 36 and 40%, respectively, and the velocities of fluids in the reservoir are estimated to be 0.4 to 14.9 m/h in the case of both tracers..
136. Khasani, Ryuichi Itoi, Toshiaki Tanaka, Michihiro Fukuda, A numerical study on the effects of initial water saturation of a geothermal reservoir on well characteristics, Memoirs of the Faculty of Engineering, Kyushu University, 64, 1, 1-15, 2004.03, The effects of initial water saturation on well characteristics in two-phase geothermal reservoirs were evaluated. A vertical wellbore model of uniform diameter coupled with a radial horizontal flow in a reservoir of uniform thickness was employed. The momentum equation for two-phase flow in a wellbore was numerically evaluated with a method introduced by Orkiszewski. The energy equation in the wellbore was assumed to be isenthalpic. Mass flow rate and pressure at a feed zone of the well were calculated using a steady radial flow in a reservoir. The numerical calculation showed that the lower initial water saturation in the two-phase reservoir leads to less total flow rate at a given wellhead pressure. However, the decrease in the initial water saturation results in an increase in the maximum discharge pressure. The initial water saturation does not affect the steam flow rate significantly for low wellhead pressure..
137. Hideki Mizunaga, Toshiaki Tanaka, Keisuke Ushijima, Tetsuo Aono, Junichi Sasaki, Reservoir Monitoring of the Onuma Geothermal Field Using Fluid Flow Tomography, Journal of the Geothermal Research Society of Japan, 10.11367/grsj1979.26.251, 26, 3, 251-271, 2004, Fluid Flow Tomography (FFT) method is an improved mise-à-la-masse method, which is used as a reservoir monitoring method. This method is a 4-Dimensional (4-D) electrical method in order to visualize the transient subsurface fluid flow by measuring charged electric potentials due to subsurface resistivity and streaming potentials caused by subsurface fluid flow. This method is utilized to monitor the fluid flow during hydraulic fracturing of Hot Dry Rock project and periodical overhaul of geothermal power plant. This method is also used to monitor the flow of heavy crude oil in oil sand formation during thermal Enhanced Oil Recovery (EOR). The observed data of FFT method can be separated into charged electric potentials derived from subsurface resistivity structure and streaming potentials due to a permeable fluid flow. In this paper we describe the algorithm of three-dimensional resistivity inversion and three-dimensional probability tomography of self-potential data. A case study of FFT method was carried out in the Onuma geothermal area. As the results of 3-D analysis of resistivity data, distinguished low resistivity anomalies were detected and resistivity discontinuities where marked with resistivity changes were detected. As the results of 3-D analysis of self-potential data, the main production zone and reinjection zone were delineated from Charge Occurrence Probability (COP) distribution. We believe that the FFT method is a useful tool to monitor the dynamic change of fluid flow behavior in a reservoir during production and reinjection operations..
138. Porras, E., Itoi, R. and Tanaka, T., Interference Test Analysis at Momotombo geothermal field, Nicaragua,, Proc. of the Internationa Workshop on Earth Science and Technology, 155-162, 2003.11.
139. R. Itoi, T.Matsuzaki and and T. Tanaka, Lumped Parameter Model Analysis for Estimating Fractions of Reinjected Water Return to Produced Fluid at Sumikawa, Japan, Geothermal Resources Council Transactions, 27, 715-719, 2003.10.
140. Ryuichi Itoi, Ryo Matsuzaki, Toshiaki Tanaka, Junko Kamei, Lumped parameter model analysis for estimating fractions of reinjected water return to produced fluid at Sumikawa, Japan, Quaternary International, 27, 387-391, 2003, Chemical monitoring data from three production wells at Sumikawa was analyzed for estimating fractions of reinjected fluid mass to produced fluids with a lumped parameter reservoir model. Fractions were simultaneously and sequentially estimated with an on-line analysis method. Produced fluids at each production well receive different magnitudes of return of reinjected fluids with time..
141. Khasani, Itoi, Tanaka, T.; Tanaka, Toshiaki;, T. and Fukuda, M., An Analysis of pressure drops in wellbore , under low flow rate conditions, shown on a deliverability curve, Proc. of the 24th New Zealand Geothermal Workshop, 115-120, 2002.11.
142. Itoi, R., Unoki, R., Gotoh, T. and Tanaka, T., Environmental Effects of Volcanic Gases on a Regional Rainwater Chemistry at Kuju, Japan, Proc. of the 24th New Zealand Geothermal Workshop,, 5月9日, 2002.11.
143. Itoi, R. and Tanaka, T., Parameter Estimating by Use of Sequential Least Squares Method in Geothermal Reservoir Engineering, Proc.of Special Workshop on Earth Science and Technology, 1-8, 2002.09.
144. Itoi, R., Tanaka, T.; Tanaka, Toshiaki;, T. and Fukuda, M., Application of Sequential Least Squares Method for Estimating Fraction of Reinjected Water Return to Produced Fluid in Water Dominated Geothermal Reservoir, Proc.of International Workshop on Intelligent Mining Systems,, 41-46, 2002.04.
145. Michihiro FUKUDA, Hidenobu NAKAMURA, Shintaro MATSUURA, Toshiaki TANAKA and Ryuichi ITOI, An Analysis of Steam-Water Tow-Phase Flow in the Geothermal Well, Proc. of the 22nd Annual PNOC-EDC Geothermal Conference, pp.89-94, 2001.03.
146. Itoi, R., Tanaka, T.; Tanaka, Toshiaki;, T. and Fukuda, M., Estimating the fraction of reinjected water returned to the production fluid at Sumikawa, Japan, Proc. of the 22nd New Zealand Geothermal Workshop, 209-214, 2000.11.
147. M. Yoshida, Toshiaki Tanaka, Ryuichi Itoi and Michihiro Fukuda, Analysis of Interference Test in Fractured Reservoir -Application of Simulated Annealing-, Geothermal Resources Council Transactions, 2000.09.
148. Toshiaki Tanaka, Ryuichi Itoi, Michihiro Fukuda, Hideki Mizunaga and Keisuke Ushijima, An Analysis Method of Fluid Flow Monitoring Using a Genetic Algorithm, Geothermal Resources Council Transactions, Vol.24, 631-635, 2000.09.
149. Torigoe, K., Itoi, R., Kai, T., Tanaka, T.; Tanaka, Toshiaki;, T. and Fukuda, M., Flux of HCl gas from the fumarolic area at Kuju volcano, Japan, IVASC General Assembly 2000, 2000.07.
150. J. P. Atmojo, R. Itoi, T. Tanaka, M. Fukuda, S. Sudaman and A. Widiyarso, Modeling Studies of Sibayak Geothermal Reservoir, Northern Sumatra, Indonesia, Proc. of the World Geothermal Congress 2000, 2037-2043, 2000.05.
151. Toshiaki Tanaka, Hidenobu Nakamura, Ryuichi Itoi and Michihiro Fukuda, An Analysis Method of Tracer Tests by Using Genetic Algorithms and Its Application, Proc. of the World Geothermal Congress 2000, 2953-2957, 2000.05.
152. Itoi, R., Yoshioka, K., Tanaka, T.; Tanaka, Toshiaki;, T. and Fukuda, M., A Method for Estimating Reinjected Water Returns Using Natural Tracers, Proc. of the World Geothermal Congress 2000, 2635-2640, 2000.05.
153. Itoi, R., Noguchi, H., Tanaka, T.; Tanaka, Toshiaki;, T. and Fukuda, M., Laboratory Experiments on Formation Damage Caused by Inflow of Drilling Mud Water, Proc. of the 21st Annual PNOC EDC Geothermal Conference, 101-105, 2000.03.
154. Ryuichi Itoi, Tatsuji Kai, Toshiaki Tanaka, Michihiro Fukuda, Changes with Time in HO Gas Discharge Rate from the Fumarolic Area at Kuju Volcano, Journal of the Geothermal Research Society of Japan, 10.11367/grsj1979.22.159, 22, 3, 159-169, 2000.01, The discharge rate of HC1 gas from the fumarolic area at Kuju volcano had been estimated on the basis of distributions of Cl- concentration in rainwater and precipitation. The rain collectors of open type were set at eleven locations. within 7 km from the main fumarolic area. The rainwater was collected and then analyzed for chemical, compositions at intervals of two weeks from March to December during 1993-1997. The HC1 discharge rate in 1995 was stable at about 2.0 t/d until, early in July, and then increased abruptly to 6.7 t/d late in July. This increase of the HC1 discharge rate can be a precursor of the phreatic eruption on 11 October 1995. The maximum discharge rates were observed from April to May in 1996. In this period, both seismic activities below the fumarolic area and the energy discharge from the new craters increased. The discharge rate of HC1 decreased from July. 1996 with some fluctuations..
155. Keisuke Ushijima, Hideki Mizunaga, Toshiaki Tanaka, Reservoir monitoring by a 4-D electrical technique, Leading Edge, 18, 12, 1422-1424, 1999, A multichannel geoelectrical system and software for data acquisition, processing and interpretation was developed. The method, called fluid-flow tomography (FFT), was used for direct imaging of fractures and an extension of geothermal reservoirs, and to monitor an oil reservoir during thermally enhanced oil recovery. The fluid-flow behavior in the subsurface can be monitored and visualized by the technique, providing time-series data of charged potentials and self-potentials, fluid-flow fronts visualizations and quantifications, symmetric anomaly due to anisotropic permeability of the formation, and 3D fractures distribution..
156. Keisuke USHIJIMA, Hideki MIZUNAGA and Toshiaki TANAKA, Direct Imaging of Fractures by Stimulating Reservoirs, Proc. 4th SEGJ Int. Sympo. Geotomography, pp.239-244, 1998.12.
157. Ryuichi ITOI, Kentaro IMURA, Toshiaki TANAKA and Michihiro FUKUDA, An Estimating Method of Fraction of Reinjected Water to Produced Fluid on the Basis of a Lumped Parameter Model, Proc. of the 19th Annual PNOC-EDC Geothermal Conference, pp.21-125, 1998.03.
158. Calculation of electric potential due to a buried current source in a layered earth.
159. Basic Study on Effect of Reinjection Condition on Geothermal Field Production.
160. Estimation of Charged Potentials for the Fluid-Flow Monitoring Method.
161. Hideki Mizunaga, Toshiaki Tanaka, Hideshi Kaieda, Keisuke Ushijima, Fluid flow monitoring system of a geothermal reservoir by electrical prospecting, Memoirs of the Faculty of Engineering, Kyushu University, 55, 4, 505-512, 1995.12, An advanced geophysical technique for reservoir monitoring by electrical prospecting has been developed by the joint research of Kyushu University and CRIEPI work in related to fracture evaluation at the Hot Dry Rock Geothermal Power Project in the Ogachi area. The Fluid Flow Tomography survey method utilizes a casing pipe itself as a charged current electrode similar to the mise-a-la-masse method. The method has been applied to monitor fluid-flow behaviors during massive hydraulic fracturing operations and fluid-circulation experiments from injection to production boreholes. In the automatic recording system controlled by a personal computer charged potentials (mV/A) and spontaneous potentials (mV) can be simultaneously measured as a function of time at multiple stations (120ch) surrounding an operating borehole. Fluid-flow behavior in the subsurface could be visualized as a function of time by using contour maps of residual potentials from SP data and relative changes of apparent resistivity due to dynamic reservoir stimulations..
162. Hideki Mizunaga, Toshiaki Tanaka, Hideshi Kaieda and Keisuke Ushijima, Fluid flow monitoring system of a geothermal reservoir by electrical prospecting, Memoirs of the Faculty of Engineering, Kyushu University, 55, 4, 505-512, 1995.01.
163. H KAIEDA, T TANAKA, H MIZUNAGA, K USHIJIMA, FLUID-FLOW MONITORING BY VERTICAL ELECTRIC PROFILING METHOD IN OGACHI HDR SITE, AKITA PREFECTURE, JAPAN, 20TH ANNIVERSARY - GEOTHERMAL RESOURCES COUNCIL, 16, 497-499, 1992.12.
164. H. Kaieda, T. Tanaka, H. Mizunaga and K. Ushijima, Fluid flow monitoring by vertical electric profiling method in Ogachi HDR site, Akita prefecture, Japan, Transactions of Geothermal Resource Council, 16, 497-499, 1992.10.


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