[H-SC07] 地球温暖化防止と地学（CO2地中貯留・有効利用、地球工学）

[HSC07-08] Monitoring hydromechanical responses in aquifer by distributed fiber-optic strain sensing: From lab to field

*張 毅^1,2、薛 自求^1,2、橋本 励^1,2、朴 赫^1,2 (1.二酸化炭素地中貯留技術研究組合、2.公益財団法人地球環境産業技術研究機構)

キーワード：分布型光ファイバひずみセンサ、帯水層透水試験、ハイドロメカニカル変形、CO2地中貯留

Pore fluids control deformation of porous media by the fluid-to-solid hydromechanical (HM) coupling in which a change in fluid pressure can modify the effective stress and deform the porous medium (Wang, 2000). The HM coupling mechanism provides a possibility that to understand aquifer characteristics and fluid activities during fluid extraction and/or injection operations, e.g., in geological CO₂ storage (GCS), by monitoring rock strain changes. We successfully measured such HM deformations using a high-resolution distributed fiber optic strain sensing (DFOSS) tool in both laboratory and field scale studies. From the DFOSS-obtained HM information, we are able to track the pressure impact zone, understand the permeability structure of the aquifer formation and identify the preferential flow layers. Moreover, we can track the fluid migration front during CO₂ displacing water and the mechanical response of CO₂ breaking through to a low-permeability layer or caprock. The application of DFOSS would be beneficial to guide the aquifer pressure management for safe GCS with prior or simultaneous water extraction (Buscheck et al., 2012).