Effect of irreversible and unstable processes on reservoir recovery

Abstract

Hysteresis behaviour, during filtration, is caused by lithological differences in geo-fluid-dynamical media, geological-physical characteristics, and properties of saturating fluids. Typically, irreversible changes are caused by excessive external loads on the investigated porous media. The proposed solutions are part of a new concept of unsteady water flooding, which allows for early prediction of water breakthrough into production wells. This text discusses the negative impact of hysteresis phenomena on oil recovery and proposes a solution. To solve this task, control parameters, based on growth models and catastrophe theory, are selected so to predict local instability and irreversibility before the bifurcation moment., Herewith it is necessary to develop technologies, which can prevent irreversible changes in permeability, capillary retention of oil, oil degassing, and to consider the unstable behavior of the displacement front. Systemic optimization of oil field development aims to increase oil production, effectively mobilize, save injected and recovered water and gas. Keywords: hysteresis; instability; irreversible changes in permeability and porosity; phase transition; capillary forces; oil recovery.