Prediction Method of Bottom Water Coning Profile and Water Breakthrough Time in Bottom Water Reservoir without Barrier

Abstract

During the exploitation of bottom water oil reservoir, bottom water coning influences the breakthrough of bottom water significantly. Because water cut rises quickly after the breakthrough of bottom water, measures should be taken before the breakthrough to postpone production period without water, thus improving oil recovery. So accurate prediction of water coning profile and breakthrough time is very essential. Through mathematical derivation, this paper proposed a prediction method of bottom water coning profile and bottom water breakthrough time in bottom water reservoir without barrier. Based on theory of fluids flow in porous media, this paper assumes that the flow models are plane radial flow in opened intervals and spherical radial flow in unopened intervals. Further, factors of fluid viscosity, irreducible water saturation, residual oil saturation, and oil-water contact (OWC) movement are also taken into account. Compared with other prediction equations, this method achieves more precise bottom water breakthrough time, and the relative deviation is only 1.14 percent.