Emulsified Epoxy Resin for Mitigating Sand Production

Abstract

Sand production from unconsolidated or crushed weakly consolidated formations due to high reservoir fluid flow velocity leads to operational problems and limits their potential. Many techniques are practiced by the completion and production engineers to combat such challenge. This paper discusses the development and testing of a novel polymeric resin formulation that consolidates sand grains to form a high regained permeability and high compressive strength rock matrix, allowing high production rate without sanding concern. The new chemical solution utilizes a low viscosity water external epoxy emulsion to strengthens the bonding of sand grains while maintains flow capacity. The chemical formulation contains two components that can be batch mixed at wellsite, injected by coiled tubing or drill pipe, and shut-in in the formation to cure for 24 to 48 hours depending on the reservoir temperature from 200°F to 320°F. Unlike most of the currently used resin consolidation products, by which post flush is required to maintain opening of the pore space, the emulsion separates during the curing process with epoxy attaching to the sand surface while the water phase occupies the pore to help keep the flow path open. Laboratory experiments in both water or oil saturated sand packs showed the treated loose sand are well consolidated with the unconfined compressive strength significantly greater than 1000 psi and the regained permeability up to 54%. No sand production was observed in the produced fluid at high flow rates. This paper focuses on the laboratory testing of the water external emulsified epoxy. The chemical mechanism and evaluation methodology are described. Having the water emulsified epoxy resin system allows the convention water based diverting techniques such as foam to be used during treatment of long sections. Another benefit of the water based emulsified epoxy is its operation simplicity and safety. The flash point concerns for safe field operation is completely alleviated with this chemical formulation.