Mechanism Study of Disproportionate Permeability Reduction Using Nuclear Magnetic Resonance T2

Abstract

Excessive water production is an enduring problem in the oil industry that has always been an unbearable burden on the environment and a great damage to the ultimate oil recovery. Gel treatment has been routinely used for decreasing water production. Disproportionate permeability reduction (DPR) is a natural phenomenon in some polymer gels that can reduce the permeability to water more than to oil. The conformance improvement treatments with DPR can effectively reduce the water cut without substantially reducing the oil productivity in fractured reservoirs. At present, there are no widely accepted mechanisms of oil-phase permeability development and DPR. In this paper, nuclear magnetic resonance is applied to study the mechanisms of oil-phase permeability development, DPR, and permeability influence by scanning different core samples treated with Cr(III)–acetate–hydrolyzed polyacrylamide polymer gels. Results show that the permeability difference leads to a certain alteration in NMR T2 curves, but final c...