Geomechanics analysis of caprock integrity in injection and production operations of aquifer gas storage

ABSTRACT

The safety of aquifer gas storage (AGS) depends on the mechanical stability of the caprock to a great extent. The injection and production operation of AGS will cause the disturbance of the in-situ stress due to the change of pore pressure in the reservoir and caprock, which may lead to the failure of caprock. The con AGS is established based on geological structure and hydrogeological information. By using the finite element method, the factors such as boundary condition, properties of reservoir and caprock, and in-situ stress coefficient are considered, respectively, and the variation of formation pressure and disturbed stress in the process of injection and production are analyzed. The results show that the boundary conditions are of significant influence on the stress field. The shear failure risk of reservoir–caprock interface under closed boundary is the greatest. The in-situ stress coefficient has the greatest influence on the failure risk of the caprock, followed by the permeability of the reservoir and caprock.

KEYWORDS:

• Aquifer gas storage
• hydro-mechanical coupling
• numerical simulation
• ABAQUS

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability Statement

The datasets used or analysed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

The work was supported by the the National Natural Science Foundation of China [42072166]; Key R&D Program of Heilongjiang Province of China [JD2023SJ26]; Natural Science Foundation of Heilongjiang Province of China [LH2020D004]; State Key Laboratory for GeoMechanics and Deep Underground Engineering [SKLGDUEK2001].