| 講演要旨(和文) | | CO2地中貯留では圧入CO2 の流動挙動は貯留岩の種類、温度圧力条件により変化すると考えられている。本研究では、ベレア砂岩と多胡砂岩を岩石コア試料とし、両端面に印加電極、側面にリング状の計測電極を取り付け、超臨界CO2の圧入に伴う比抵抗変化を測定することで、種類の異なる岩石内でのCO2 流動挙動を評価することを目的とし室内実験を行った。測定の結果、ベレア砂岩ではCO2が均等に浸透し、地層水との置換率は平均約50%となった。多胡砂岩では、CO2の浸透が均等ではなく流入側で約50%、流出側で33%の置換となった。試料の層理面の状況、比抵抗変化の比較から、層理面分布の粗密の影響によりCO2の浸透が抑制され、CO2の浸透が不均一になったため置換率が流入側と流出側で変化したと考えられる。本実験の結果から、比抵抗計測による流動挙動の違いのモニタリングの可能性が示された。 |
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| | 講演要旨(英文) | | With CO2 sequestration, it is thought that flow behavior of injected CO2 changes with type of reservoir rock, and temperature pressure condition. In this research, measurement of resistivity change due to injection of supercritical CO2 was conducted to estimate the difference of CO2 flow behavior in different type of rocks, by using Berea and Tako sandstones. By setting the impression electrode on the both end and the measurement electrode of ring condition on the side of the rock sample, migration of CO2 was detected. From the result, with the Berea sandstone CO2 permeated equally, and the average of replacement ratio of the brine became approximately 50%. With the Tako sandstone, the permeation of CO2 was not equal and replacement ratio became approximately 50% on injection side, and 33% on outflow side. From the comparison of bedding plane of the sample and resistivity change, it is thought that replacement ratio of Tako sandstone changed on injection side and outflow side because of the influence of bedding plane distribution. The permeation of CO2 was controlled by the bedding plane and becomes uneven. From the result of this experiment, possibility of monitoring the difference of the flow behavior with resistivity measurement was shown. |
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