Poroelasticity in PyLith

Representation of Cryer's problem - a fluid saturated porous sphere
subjected to an instantaneous radial compressive stress.

Poroelasticity refers to the coupling between mechanical deformation and fluid flow and is a process that is ubiquitous to the geosciences. Within crustal properties alone, poromechanics provide a governing framework to describe the processes behind subsurface hydrology, petroleum reservoirs and production, seismic activity, carbon capture and storage, and geothermal energy.

Prior efforts to incorporate poroelasticity within the PyLith framework have relied on a coupled approach employing a separate reservoir simulator in conjunction with the mechanical modeling capability built into PyLith. While permitting a specialized and refined means of modeling flow, this effectively required the consideration of two separate problems, with two separate modeling domains, and two separate means of simulation input. In addition, the iterative transfer of information between two separate models for fluid flow and mechanics reduced the ability for solver optimization.

With the upcoming version of PyLith, we have leveraged the new design to allow for the representation of multiphysics within what was formerly solely a mechanics code. This permits the solver flexibility and domain decomposition capabilities of the PETSc package, serving as the mathematical engine of PyLith, to be applied to the entire modeled domain. (continued)