13:45 〜 14:00
[HSC06-13] 非構造帯水層への最適CO2圧入・貯留法の数値的検討
キーワード：CO2地中貯留、数値シミュレーション、最適圧入法、非構造帯水層貯留、坑井形状
CO2 injected into a non-structural saline aquifer migrates upward due to the buoyancy, accumulates beneath a caprock, and spreads laterally forming thin layer. As a result, injecting CO2 from a feed point at the bottom of the reservoir may result in poor sweep efficiency and large lateral footprint. It can lead to the undershooting of the storage amount of CO2 and migration outward the approved storage area, which can be a major problem in Japan where each reservoir does not necessarily have a large capacity.
In this presentation, we will report the results of numerical investigation on the optimal CO2 injection method into a non-structural aquifer. We assumed different well configurations including inclination and feed zone, and numbers of the injection wells to investigate the achievement of the stored amount of CO2, the sweep efficiency of the injected CO2, and the footprint.
For the simulation, 3D model of which X × Y × Z = 6 km × 6 km × 200 m was built. The reservoir with thickness of 100 m locates at a depth of 950 to 1,050 m, which is sandwiched between low permeable seal and basement. The horizontal permeability of the reservoir was assumed to be 100 mD. Different vertical permeability of 1, 10, and 100 mD was assumed to investigate the effect of the anisotropy of the permeability. Numerical simulations for 100 years including the injection period of 20 years at a rate of 1 Mt-CO2/year were carried out. Fluid flow simulations were carried out using the "STAR" reservoir simulation code (Pritchett, 1995; Pritchett, 2002) with the equations of state "SQSCO2" package (three pore components: H2O, CO2 and NaCl) (Pritchett, 2008).
Note that the reservoir was assumed to be homogeneous and porous in this study, so that the effects of heterogeneity and fractured reservoir were left to be considered (Kano et al., 2020). Injection schedule of each well also remains open for consideration. Preliminary numerical investigation based on the actual site can be useful for planning the optimal injection and storage of CO2.
References
Kano et al. (2020): Effects of Heterogeneous Seal Layer Property on The Long-Term Behaviour of CO2 Injected into Deep Multilayer Systems, Journal of MMIJ, 136, 140-150.
Pritchett, J.W. (1995): STAR-a geothermal reservoir simulation system. Proc. World Geothermal Congress, Florence, 853-858.
Pritchett, J.W. (2002): STAR User’s Manual Version 9.0, SAIC Report Number 02/1055
Pritchett, J.W. (2008): New "SQSCO2" equation of state for the "STAR" code, SAIC.
In this presentation, we will report the results of numerical investigation on the optimal CO2 injection method into a non-structural aquifer. We assumed different well configurations including inclination and feed zone, and numbers of the injection wells to investigate the achievement of the stored amount of CO2, the sweep efficiency of the injected CO2, and the footprint.
For the simulation, 3D model of which X × Y × Z = 6 km × 6 km × 200 m was built. The reservoir with thickness of 100 m locates at a depth of 950 to 1,050 m, which is sandwiched between low permeable seal and basement. The horizontal permeability of the reservoir was assumed to be 100 mD. Different vertical permeability of 1, 10, and 100 mD was assumed to investigate the effect of the anisotropy of the permeability. Numerical simulations for 100 years including the injection period of 20 years at a rate of 1 Mt-CO2/year were carried out. Fluid flow simulations were carried out using the "STAR" reservoir simulation code (Pritchett, 1995; Pritchett, 2002) with the equations of state "SQSCO2" package (three pore components: H2O, CO2 and NaCl) (Pritchett, 2008).
Note that the reservoir was assumed to be homogeneous and porous in this study, so that the effects of heterogeneity and fractured reservoir were left to be considered (Kano et al., 2020). Injection schedule of each well also remains open for consideration. Preliminary numerical investigation based on the actual site can be useful for planning the optimal injection and storage of CO2.
References
Kano et al. (2020): Effects of Heterogeneous Seal Layer Property on The Long-Term Behaviour of CO2 Injected into Deep Multilayer Systems, Journal of MMIJ, 136, 140-150.
Pritchett, J.W. (1995): STAR-a geothermal reservoir simulation system. Proc. World Geothermal Congress, Florence, 853-858.
Pritchett, J.W. (2002): STAR User’s Manual Version 9.0, SAIC Report Number 02/1055
Pritchett, J.W. (2008): New "SQSCO2" equation of state for the "STAR" code, SAIC.