Mitigating Sustained Casing Pressure in the Denver-Julesburg Basin with a Low Permeability Flow Resistant Cementing Solution

Abstract

Sustained casing pressure (SCP) is an industry wide challenge, and the evaluation and validation of a new cement system proactively mitigates SCP defending against numerous flow mechanisms, by delivering a barrier that minimizes fluid loss, shortens transition time, improves shear bonding, and reduces permeability. The application of this new cement system in the Denver-Julesburg Basin demonstrates its ability to mitigate and reduce the occurrence of SCP both pre and post fracturing while delivering a more efficient and sustainable solution. The innovative chemistry of the cement system enables an efficient delivery of a dry blended system, providing enhanced cement properties without the need for premium liquid additives. The system was evaluated in the laboratory to mitigate SCP caused by flow through unset cement as well as evaluated for its long-term integrity to better withstand stresses placed on the cement sheath during fracturing operations. Pre and post frac SCP are well documented and monitored across the Denver-Julesburg (D-J) basin and the new cement system was pumped on over 200 wells and has shown a reduction in both pre- and post-fracturing SCP (COGCC 2022). The SCP mitigation cement system can deliver over a 40% increase in shear bond strength, increasing the anchoring forces the cement sheath has to the casing and formation while proving to be a more crack resistant barrier. With a 75% reduction in cement permeability, it has increased resistance to flow and degradation from corrosive fluids or gases. The cement system enables operators to proactively mitigate SCP, minimize risk, and limit their carbon footprint by eliminating the need for future remediation and can be tailored and applied to other basins with similar challenges across the globe to mitigate SCP and improve long term well integrity