Gas flow and solid deformation in unconventional shale

Shale, a material that is currently at the heart of energy resource development, plays a critical role in the management of civil infrastructures. Whether it concerns geothermal energy, carbon sequestration, hydraulic fracturing, or waste storage, one is likely to encounter shale as it accounts for approximately 75% of rocks in sedimentary basins. Despite the abundance of experimental data indicating the mechanical anisotropy of these formations, past research has often simplified the modeling process by assuming isotropy. In this study, the anisotropic elasticity model and the advanced anisotropic elastoplasticity model proposed by Semnani et al. (2016) and Zhao et al. (2018) were adopted in traditional gas production and strip footing problems, respectively. This was done to underscore the unique characteristics of unconventional shale. The first application example reveals the effects of bedding on apparent permeability and stress evolutions. In the second application example, we contrast the hydromechanical responses with a comparable case where gas is substituted by incompressible fluid. These novel findings enhance our comprehension of gas flow and solid deformation in shale.