oa Geomechanically-derived Fault Zone Petrophysical Properties – A Synthetic Fault Model Study

A 2D geomechanical model of a fault zone has been used to develop porosity and permeability distributions that reflect the geomechanical rock damage. A pseudo-3D geomodel, where fault displacment varies from zero to maximum has been created and a method developed to appropriately populate it with porosity and permeability values. Both dilational and compactional deformation occurs in this normal fault,as is expected in real subsurface faults, resulting in both increased and decreased (relative to the matrix) permeability values. Geometrically equivalent geomodels using a range of transmissibility multiplier to represent the fault have also been generated. These six geomodels (5 with transmissibity multipliers and 1 with geomechanically-derived poroperm) have then been converted into an industry-standard flow simulation that vary only in the treatment of petrophysical properties around the fault zone. The resulting flow simulations show that the geomechanically-controlled poroperm properties to a better job of representing the kind of complexity of e.g. across-fault pressure regimes and fluid saturations that are encountered in subsurface reservoirs.