Journal of MMIJ

Special Edition for Recent Research Current on a Coupled Problem of Pore Pressure and Deformation of Rock

Published: May 01, 2012 Updated: May 01, 2012

Displaying 1-6 of 6 articles

Volume 126 (2010) Issue 10_11 Pages 583-591 Published: May 01, 2012
CCS's Position in Japan's Energy Policy
Hirotoshi KUNITOMO

Presently, CCS is recognized globally as the essential option to realize the clean fossil energy usage under the climate change constraint. Especially, coal fired power generation is still major part of world total power generation supply. In order to reduce carbon dioxide emitted from coal fired power plants, not only the improvement of generation efficiency but also introduction of CCS is considered as the essential measure to secure the stable social development and enenrgy supply. In this report, present status of Japan and international discussion for CCS, R&D and demonstration of CCS and Japanese strategy for Zero emission coal fired power generation is reviewed and discussed.
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Volume 126 (2010) Issue 10_11 Pages 592-601 Published: May 01, 2012
The Latest Situation of Risk Assessment of Carbon Dioxide Geological Storage
Atsuko TANAKA, Yasuhide SAKAMOTO, Takeshi KOMAI

In this paper, the authors review the latest situation of risk assessment research efforts on to "Carbon Dioxide Geological Storage (geological CCS)" technology. After publication of the special report on geological CCS (2005) with sections about risk assessment, significant progresses have been achieved in risk assessment as technological evaluation of geological CCS as one of likely greenhouse gas discharge reduction measure. Those efforts produced permission scheme or safety guideline for geological CCS in some countries. On the other hand, as regard with research and development for precise risk assessment and management of CO₂ Geological Storage, it is on the halfway of establishing methodologies. To establish quantitative assessment methodology for rational and reasonable risk governance of this field, the following additional research and development efforts are still urgently required: hazard data collection, data preparation for evaluation about surface facilities and surface local environment, and establishing methodology for uncertainty treatment of geological formation.
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Volume 126 (2010) Issue 10_11 Pages 602-607 Published: May 01, 2012
Geological CO₂ Storage by Underground Coal Gasification
Sohei SHIMADA, Hitoshi KOIDE, Ken-ichi YAMAZAKI

Coal is generally used as solid fuel on the surface after open cut mining or underground mining. However, the coal seam mined economically is limited by the geological and technological conditions. In situ method is a promising method, which enables the energy recovery from deep coal seam and under sea coal seam, usually being not economical by conventional mining methods. In "in situ" method the coal is usually converted to gaseous form underground (UCG: Underground Coal Gasification). One of the features of this method is the CO₂ storage in coal seam in parallel to the gas production.
There are two methods for UCG, combustion and non-combustion methods. The former is the conventional UCG realizing the coal gasification by supplying heat through the combustion of coal seam. The other one is non-combustion method using microbial decomposition and supercritical CO₂ extraction for gas production at temperatures of some 10 or 100 degrees Celsius. The CO₂-reducer methanogenic archaea are found in underground coal seams, in petroleum reservoirs and in saline aquifers in Japan. The underground bioreactors for CO₂-reduction and methanogenesis may be realized in deep coal measures or in underground hydrocarbon accumulations.
The former UCG is now booming up for the technology development in the world now towards commercialization. The latter UCG is the still in the R&D stage. This report summarizes the present state of arts of these two UCG methods pressing the gas production and CO₂ storage in coal seam.
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Volume 126 (2010) Issue 10_11 Pages 608-613 Published: May 01, 2012
Study on CO₂ Sorption on Coal Measured by Heat of Sorption and Spin-Spin Relaxation
Naoto SAKIMOTO, Sohei SHIMADA, Kotaro OHGA, Haruo KUMAGAI, Osamu YAMADA, Mamoru KAIHO, Hajime YASUDA

CO₂ sorption on coal was estimated by two experiments, one is heat of sorption measurement and the other is ¹H-NMR measurement. In the heat of sorption measurement, differential heat of sorption (q_d) was compared with the calculated one. Measured q_d was same value with calculated one at low pressure. It decreased gradually with pressure and became lower than the calculated one. Since it couldn't be explained by the theory based on physisorption, it is estimated that the coal-CO₂ system could not be explained by only simple physisorption.
In ¹H-NMR measurement, spin-spin relaxation time (T₂) and composition fractions of L₁, L₂ and G were measured. Composition fractions and T₂ of L₁ increased with CO₂ gas pressure. Furthermore, the correlation was observed between volume increments and dissolution amount at over 10 atm. It indicates that part of CO₂ sorption capacity was used to coal relaxation.
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Volume 126 (2010) Issue 10_11 Pages 614-622 Published: May 01, 2012
Experimental Evaluation of Permeability of Coal in Supercritical CO₂ and N₂ Injection Under Stress and Strain Restricted Conditions
Tamotsu KIYAMA, Soshi NISHIMOTO, Masaji FUJIOKA, Zique XUE, Daisuke MIYAZAWA, Yoji ISHIJIMA

A micro pilot test of CO₂-enhanced coal bed methane (CO₂-ECBM), which is a carbon capture storage (CCS) technique for global warming prevention, was carried out in Yubari. CO₂ was injected into a coal seam, which consisted of a cleat and a coal matrix, and the injection rate of CO₂ was decreased with time. The matrix swelled as CO₂ was adsorbed. Depending upon the constraint conditions, the cleat closed with CO₂ injection, and the permeability decreased. In this study, the strain and stress constraint conditions were created in-laboratory and N₂ and supercritical CO₂ were injected repeatedly in a coal specimen for observation of the permeability, Vp, circumferential strain and confining pressure. In order to achieve the strain constraint condition, a circumferential extensometer was installed in a cylindrical specimen and the output was used to servo-control the confining pressure intensifier. In order for the matrix to adsorb CO₂ and swell, supercritical CO₂ was injected into the coal seam under the strain constraint conditions, the cleat (passage of flow) was closed, and infiltration of supercritical CO₂ was restrained for a short time, and flow was then suspended. A swelling pressure of approximately 6 MPa was observed at this time with adsorption of supercritical CO₂ onto coal. When N₂ was re-injected into the coal specimen in which supercritical CO₂ was injected under the strain constraint conditions, no immediate flow was generated. However, several hours later, when permeation began, the flow was progressively increased. Although the matrix might have adsorbed CO₂ and swelled when supercritical CO₂ was re-injected into the coal under stress constraint conditions, the cleat was not closed; therefore, infiltration of supercritical CO₂ was continued and the flow was not stopped. A swelling strain of approximately 0.6% with adsorption of supercritical CO₂ on coal was observed at this time.
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Volume 126 (2010) Issue 10_11 Pages 623-626 Published: May 01, 2012
Japan CCS is Advancing
Masanori ABE

Japan CCS Co., Ltd. was incorporated on 26th May 2008 by investment of total 29 Japanese major private companies for the purpose of conducting a total investigation for CCS demonstrations, and early extensive dissemination of CCS in Japan. In the spring of 2009, the company increased its capital and allocated new shares to new shareholders. The total number of shareholders became 37 companies as of 31st July 2009.
The company is conducting two projects in the fiscal year 2009; one is the Demonstration Project of the CO₂ Abatement Technology, which was assigned by the Ministry of Economy, Trade and Industry, and the other is a part of the Feasibility Study on a Total System from Electric Power Generation to CO₂ Storage, which was assigned by the New Energy and Industrial Technology Development Organization.
As a part of the former project, the company is carrying out 3D seismic survey for a site characterization and an offshore pipeline route survey over two candidate sites for a CCS demonstration project in Japan.
Several monitoring methods are also considered for the CCS demonstration project. 3D and 2D seismic survey and VSP are considered for monitoring of injected CO₂ distribution in the reservoir, chemical and physical marine surveys for seepage detection, and seismicity monitoring for assessing any impact to the surface and subsurface facilities of the CCS demonstration.
The Japanese Government together with Japan CCS Co., Ltd. and private sectors is advancing toward CCS demonstrations.
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