Numerical Simulation Applied to Characterize Induced Anisotropy in Densely Fractured Poroelastic Media

Abstract

Many hydrocarbon reservoirs are naturally fractured, and fracture orientation and distribution is an important subject of research, since fractures control the permeability of the reservoir. In this work presents a methodology to determine a viscoelastic transversely isotropic (VTI) medium long-wave equivalent to a fluid-saturated densely fractured poroelastic medium. The long-wave assumption implies that the VTI approximation is valid for fracture distances and fracture apertures much smaller than the average wavelengths of the predominant travelling waves. The fractures are modeled as discontinuities in displacements in the solid and fluid displacements and fluid pressures across fractures. The coefficients of the VTI medium are obtained using harmonic experiments on representative samples of the poroelastic material. In particular, the sensibility of VTI to variations in pore pressure is analyzed.