Remedial Sand Control Using Chemical Sand Consolidation, A Field Experience

Abstract

Abstract Weak and loose sand grains that make up oil and gas formation matrix can be strengthened by chemical bonding while still maintaining the desired permeability for optimum production. This case study involves a well with high sand production rate that led to surface equipment failure and eventual shut down of an entire flow station for months. This paper discusses the application and results of the deployment of a chemical sand consolidation fluid system on the candidate well. The process involves mixing and squeezing the system into the formation and allow it to set. Once cured, the system forms an artificial core with a high compressive strength and permeability thereby preventing the well from producing sand. The system is externally catalyzed with two major additives in the mix that work in synergy to enhance wettability of the formation materials and to increase unconfined compressive strength of unconsolidated sand. In selecting a candidate well, formation data including bottom hole temperature and pressure, interval length, permeability, porosity and mineralogy were carefully studied and analyzed to build a geo-mechanical model that predicts minimum unconfined compressive strength (UCS) for sand sand-free production. Laboratory model and sanding assessment were carried out by developing cores using actual well formation materials. The fluid system was prepared and flown through cylindrical cores in the laboratory under reservoir conditions. Actual field deployment was carried out using coiled tubing. The well was shut-in for 24hrs after treatment and opened up for sand free production. Post treatment analysis of the surface cores made during deployment yielded a UCS of 789Psi and permeability to brine that stabilized at 1963mD.