COMBINED METHOD OF STIMULATING A HETEROGENEOUS RESERVOIR BASED ON OXIDATION REACTIONS

Abstract

This article discusses the issue of enhancing oil recovery from a heterogeneous reservoir. The combined method is based on the technology of in-situ combustion with the injection of a slug of urea solution. The in-situ combustion technology itself is a combination of hot water or steam injection with a transition to air injection. This makes it possible to initiate combustion directly within the reservoir. Subsequently, a transition to a wet or super-wet combustion process is envisaged. For more efficient displacement of oil from a layered heterogeneous reservoir, it is     proposed to inject a slug of urea solution at the stage of wet in-situ combustion. In this case, the main properties of urea under the influence of high temperature are utilized. At high temperatures, urea decomposes into ammonia and carbon dioxide. Dissing in water, ammonia forms an alkali, due to which the interfacial tension at the phase boundary and rocks decreases, and wettability    improves. Carbon dioxide dissolves both in water and, to a greater extent, in oil. This contributes to a reduction in oil viscosity. All these factors combined allow for an additional increase in oil production from a heterogeneous reservoir.