An Efficient Numerical Model for the Evaluation of the Productivity Considering Depletion-Induced Plastic Behaviors in Weakly Consolidated Reservoirs

Efficient and accurate modeling of rock deformation and well production in weakly consolidated reservoirs requires reliable and accurate reservoir modeling techniques. During hydrocarbon production, the reservoir pressure is dropped, and rock compaction is induced. In such depletion-induced reservoir rock deformation, both elastic and plastic deformation can be generated. The numerical investigation of depletion-induced plasticity in shale oil reservoirs and its impact on coupled reservoir modeling helps provide insights into the optimization of horizontal well productivity. This study introduces a coupled flow and geomechanical model that considers porous media flow, elastoplastic deformation, horizontal well production, and the coupling between the flow and geomechanical processes. Simulation results are then provided along with numerical modeling parameters. Effects of relevant parameters, including depletion magnitude, rock mechanical properties, and hydraulic fracture parameters, jointly affect rock deformation, rock skeleton damage, and horizontal well productivity. Depletion-induced plasticity, stress, pressure, and subsidence are all characterized by the solution strategy. In addition, the implementation of direct and iterative solvers and the usage of full coupling and sequential coupling strategies are investigated, and the associated solver performance is quantified. It helps evaluate the numerical efficiency in the highly nonlinear numerical system. This study provides an efficient coupled flow and elastoplastic model for the simulation of depletion in weakly consolidated reservoirs.