著者

加野 友紀 石戸 経士 中尾 信典

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.136, no.12, pp.140-150, 2020-12-31 (Released:2020-12-18)

参考文献数

45

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Heterogeneity in mudstone/shale layers has significant effects on seal layer integrity. The presence of intralayer sandstone channels in a seal layer may allow the buoyant CO2 to escape from the reservoir, even if the globally averaged permeability of the seal layer seems low enough. On the other hand, multi-layered structures are known to work often as baffles for the upward migration of CO2 in formations. In this paper, we investigate the storage capacity of multilayer formations with discontinuous seals. Numerical simulations are carried out to study the effects of seal layer discontinuity on the long-term behaviour of CO2 injected into deep saline aquifers. To represent a seal layer composed of low permeability rocks intersected by sandstone channels, ‘MINC' doubleporosity model is adopted. Also conducted is sensitivity analysis to investigate the effects of key parameters such as capillary pressure, relative permeability, temperature, and the thickness of the formations. The results show that CO2 injection into a sufficiently deep multi-layered reservoir enables CO2 to be stored and trapped in and around the reservoir without reaching to a shallow aquifer, even though seal layers have discontinuities. The upward movement of CO2 is greatly affected by capillary pressure of sandstone channels in seal layers. The relative permeability and the temperature-dependent CO2 properties have a significant effect on the final plume spread and the amount of CO2 dissolved or fixed by residual gas trapping.

著者

安川 香澄 内田 利弘 小関 武宏 最首 花恵 福田 大輔 松田 鉱二 柳澤 教雄 藤光 康宏 椋平 祐輔 糸井 龍一 岡部 高志 鈴木 杏奈 海江田 秀志 花野 峰行 石戸 経士 石橋 琢也 佐藤 真丈 山田 茂登

出版者

日本地熱学会

雑誌

日本地熱学会誌 (ISSN:03886735)

巻号頁・発行日

vol.37, no.4, pp.153-176, 2015-10-25 (Released:2016-04-25)

著者

石戸 経士

出版者

Tokyo Geographical Society

雑誌

地學雜誌 (ISSN:0022135X)

巻号頁・発行日

vol.114, no.6, pp.885-900, 2005-12-25

参考文献数

29

被引用文献数

6 3

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Characterizing the transport properties of reservoir-forming rocks is one of the most important tasks in reservoir engineering. We review the relationships among permeability, porosity, electrical formation factor, and electrokinetic coupling coefficient under saturated and unsaturated conditions on the basis of the capillary tube model of porous medium, by which one can relate the microscopic physics of the transport properties to the macroscopic behaviors described by Darcy's and Ohm's laws and the cross-coupling effects. These relationships together with the recent models of clay rich sandstones provide a useful guideline for interpreting core, logging, and geophysical survey data. Among various rock properties, permeability in particular needs in situ measurements such as pressure transient tests, because <I>in situ</I>i values are usually at least a few orders of magnitude larger than those measured for intact core samples due to the presence of discontinuities such as fractures in reservoirs. Concerning this topic, the concept of fractured rocks, <I>i.e.</I>, the double porosity medium and how to characterize fractured reservoirs are described.<BR>Even if the results of extensive field-wide pressure transient tests are available, in addition to drilling and various exploration data, numerical models of reservoirs are never precise, due to the problem of non-uniqueness. However, once exploitation begins in earnest, additional data become available such as temporal trends in downhole flowing pressure and enthalpy (in case of geothermal reservoirs), which may be used in history-matching studies. Because uncertainty in predictions of numerical reservoir models is directly related to the amount of field data available against which the models can be tested, it is clear that the addition of repeat geophysical survey data to the list of pertinent field measurements is likely to improve the reliability of these forecasts. Recently developed computational tools such as the EKP-postprocessor, which can calculate changes in self-potential distribution through electrokinetic coupling caused by changing underground conditions computed by reservoir simulation, enable us to use geophysical monitoring data in history-matching studies.