The Automatic Differentiation General Purpose Research Simulator (AD-GPRS) is a flexible and extensible multiphysics simulation platform. It employs automatic differentiation to construct the Jacobian allowing for an easy extension to new physics and constitutive relations, as well as for complete flexibility in the specification of independent variables, which leads to a unified simulator for different formulations and solution strategies. There are no assumptions about the underlying grid structure thus unstructured grids are supported for accurate representation of the complex structure and heterogeneity of subsurface formations. Fully implicit or sequentially implicit time-discretization schemes are available. The latter is designed for handling different physical sub-problems with flexible coupling strategies.
AD-GPRS can be used, for example, to simulate enhanced oil recovery (EOR) processes, CO2 sequestration in saline aquifers and depleted oil reservoirs, shale gas/oil production, and enhanced steam injection.