First Worldwide Application of HP/HT Water Swellable Packers Eliminates Deployment Risks and Improves MSF Efficiency in Tight Gas Reservoirs

Abstract

This paper presents the first-time application of high pressure/high temperature (HP/HT) water swellable packers worldwide for multistage fracturing completions. This technology eliminates deployment risks associated with premature swelling in high temperature oil-based muds (OBM) and improves efficiency of fracturing operations in tight gas reservoirs. The overall deployment method of this technology is similar to traditional open-hole multistage fracturing technologies that are industry standard. The main difference being that the isolation packer used is an HP/HT water swell packer that uses water/brine as the swelling medium as opposed to hydrocarbon. The technology comprises of an innovative compound that is capable of holding high differential pressure at high reservoir temperatures and maintaining permanent isolation in a relatively compact element length. The elastomer compound completed an extended qualification process to ensure fulfilling deployment and fracturing completion requirements in a specific well candidate. The outcome was an overall successful deployment and stimulation operation of multi stage completion with HPHT water swell packer technology. Water swell packer provided the ability to deploy the lower completion in high temperature/OBM environment with a significant increase of swelling factor delay and its compact length reduces stiffness in the BHA to further decrease the deployment risk. In addition, this technology provided an optimization technique for open-hole multi-stage stimulation by circulating out the drilling mud and leaving completion brine in the wellbore and annular space. Through a complete diagnostic process, it was confirmed that the water swellable packers successfully isolated each stage of the stimulation treatment. Prior to the first worldwide installation of an innovative elastomer compound, unique testing was conducted in the laboratory and in field tests to qualify the compound technology with special focus on the acid stimulation treatments domain. The elastomer compound was made of special fillers to chemically retain water in the elastomer matrix and eliminate any reverse osmosis problem present in traditional water-swellable compounds.