Numerical modeling of gas flow and solid deformation in unconventional anisotropic shale
Computers and Geotechnics, 187:107441, 2025.
Summary
This work develops a coupled simulator for gas flow and deformation in anisotropic shale, including elastoplastic behavior and fractures. The formulation combines mixed displacement–pressure finite elements with a one-dimensional finite element description of fracture flow. Compressible gas is represented explicitly, allowing the study to distinguish its response from that of a slightly compressible pore fluid. The simulations address an apparent tension between production losses associated with reduced permeability and additional gas release caused by pore compaction. Validated examples include intact shale specimens and fractured reservoirs at field scale. They examine bedding orientation, mechanical anisotropy, plastic strain development, and the role of fluid compressibility. The results distinguish ultimate recovery from production over a limited operating period: deformation-related permeability reduction can inhibit short-term output even when compaction increases ultimate recovery. Bedding-dependent permeability evolution is identified as an important production control.