Utilization of Innovative Resin-Cement Blend to Enhance Wellbore Integrity

A major challenge that is being occasionally faced during the well's lifecycle is the pressure buildup between the cemented casing annuli, also known as sustained casing pressure (SCP). Compromise of cement sheath integrity is one of the primary reasons for such a pressure buildup. This challenge prompted to develop such an isolation material that should enhance the mechanical properties of cement. The resin-cement blend system can be regarded as a novel technology to assure long term zonal isolation. This paper presents the lab testing and application of the resin-cement system, where potential high-pressure influx was expected across a water-bearing formation. The resin-cement system was designed to be placed as a tail slurry to provide enhanced mechanical properties in comparison to a conventional slurry. The combined mixture of resin and cement slurry provided all the necessary properties of the desired product. The slurry was batch-mixed to ensure the homogeneity of resin-cement slurry mixture. The cement treatment was performed as designed and met all zonal isolation objectives. Engineered solutions ultimately deliver the optimal asset value of the reservoir. During the last few decades, several laboratory investigations and field studies have been conducted to find solutions to the problem of SCP, which appears after primary or remedial cement jobs. Almost all these studies unanimously conclude that the conventional cement does not always endure the mechanical stresses imposed by the wellbore conditions and it often falls short in providing long term isolation beyond the production life of the well. When the resin is introduced into a cement slurry, it forms a dense, highly cross-linked matrix. The extent of the cross-linking reaction is governed primarily by volume, temperature, and time. The distribution of resin throughout the slurry provides a shock-absorbing tendency to the particulates of the cement. This feature increases the ductility and the resilience to withstand stress from load-inducing events throughout the life of the well. Resin-cement's increased compressive strength, ductility, and enhanced shear bond strength help to provide a dependable barrier that would help prevent future sustained casing pressure (SCP).