Numerical Simulation of Production-induced Fault Loading - Modeling Concept and Poroelastic Material Definition

An increasing number of hydrocarbon fields is affected by production-induced seismicity. The influence of far-field stresses on poroelastic stress changes during depletion as well as the interaction with faults are not well understood as analytical solutions of poroelasticity cannot account for the complex reservoir geometries encountered in reality. In order to apply suitable numerical modeling tools we test a poroelastic material model with a full coupling of the stress tensor implemented in the finite element (FE) software ABAQUS®. Using a simple model geometry the numerical simulation results of pore pressure perturbations and stress changes match well with published analytical solutions. This material definition will now be used in generic FE models of reservoirs compartmentalized by faults. Selection of model geometry, material parameters and boundary conditions are inspired by the Rotliegend gas fields of the North German Basin. The modeling concept also involves systematic parameter variations to study the effects of the initial stress state as well as of mechanical, hydraulic and fault properties onto the modeling results.