14:15 〜 14:30
[HSC06-03] CO2と水の気液二相流体における砂岩の多孔質弾性挙動の数値シミュレーション
キーワード：CO2地中貯留、多孔質弾性、間隙圧、ひずみ、二相流、数値シミュレーション
Monitoring for CO2 geological storage must determine not only the extent of the CO2 plume but also the areal extent of the pressure perturbation caused by CO2 injection. The object of the latter monitoring comes from that pre-stressed faults (if present) in the storage site may be activated by increasing pore pressure (induced seismicity). Furthermore, we should understand poroelastic effects in CO2 geological storage.
We conducted core flood experiments to examine the poroelastic behavior of Berea sandstone. The evolution of the CO2 distribution during the experiment is measured by X-ray CT. The change of strain due to core expansion can be probed by optical fiber (Distributed strain measurement) attached around the core sample. In the experiment, there is a clear difference between single-phase (water) and two-phase flow (CO2 and water) injection. In the case of a single-phase flow, the change in strain (pressure distribution) gradually decreases following Darcy’s law, whereas in the case of a two-phase flow, the strain becomes a constant value over a long distance at the steady-state. This difference is thought to be a poroelastic behavior in the multi-phase fluid system.
In this work, numerical simulation coupling the two-phase fluid flow of CO2 and water and poroelastic deformation is performed, to understand the results obtained by optical fiber strain measurement combined with X-ray CT. In our simulation, we quantify observables (CO2 saturation, pressure, strain, etc.), and try to evaluate the physical parameters by the history matching with the results of the flooding experiment. This work could shed light on the mechanism of poroelastic behavior induced by CO2 injection in the reservoir.
We conducted core flood experiments to examine the poroelastic behavior of Berea sandstone. The evolution of the CO2 distribution during the experiment is measured by X-ray CT. The change of strain due to core expansion can be probed by optical fiber (Distributed strain measurement) attached around the core sample. In the experiment, there is a clear difference between single-phase (water) and two-phase flow (CO2 and water) injection. In the case of a single-phase flow, the change in strain (pressure distribution) gradually decreases following Darcy’s law, whereas in the case of a two-phase flow, the strain becomes a constant value over a long distance at the steady-state. This difference is thought to be a poroelastic behavior in the multi-phase fluid system.
In this work, numerical simulation coupling the two-phase fluid flow of CO2 and water and poroelastic deformation is performed, to understand the results obtained by optical fiber strain measurement combined with X-ray CT. In our simulation, we quantify observables (CO2 saturation, pressure, strain, etc.), and try to evaluate the physical parameters by the history matching with the results of the flooding experiment. This work could shed light on the mechanism of poroelastic behavior induced by CO2 injection in the reservoir.