Contribution of Poroelasticity to Reservoir Engineering: Lab Experiments, Application to Core Decompression and Implication in HP-HT Reservoirs Depletion

Abstract

Abstract The linear mechanics of porous rocks is summarized : basic equations – i.e. constitutive law and fluid mass balance – and most useful relationships are given. For reservoir engineering applications, the hydrostatic loading case is dealt with in detail. The conventional diffusivity equation -i.e. uncoupled pressure equation-is then derived. Experimental procedures are suggested and results obtained on outcrop and reservoir sandstones are given. The data indicate that the sandstones have a nonlinear behavior and that volumetric coefficients are functions of the difference between the confining pressure and the pore pressure. A model is then proposed based on Biot's semilinear theory. The reservoir rock behavior is shown to be in agreement with this model for the experiments performed. As an application effective stress is computed. Finally the role of pore pressure in damaging cores during the pulling out phase is investigated.