Reclaiming the Operating Window: A Managed Pressure Cementing Workflow to Achieve Zonal Isolation Success in a Mature Field

Abstract

Successfully cementing production casing strings is one of the main challenges of well construction in mature fields. The implementation of cementing best practices can be difficult in the narrow pore pressure-fracture pressure (PPFG) window associated with reservoir depletion and complex well architecture. The increased risk of losses can lead operating teams to compromise on these best practices, often jeopardizing the zonal isolation objectives. This can result in significant additional time, cost, and production deferral/loss. Managed pressure cementing (MPC) is a viable technique to address these challenges. Using the managed pressure drilling (MPD) system's capability to precisely control bottomhole pressure, coupled with the use of mud weights that are lower than conventionally needed can expand the PPFG window; enabling operating teams to achieve a higher success rate in meeting the zonal isolation objectives. This paper will offer an optimized design methodology and critical considerations and parameters for MPC operations. It will also briefly describe the primary applications of MPC and specific, unique design considerations associated with each, namely, (1) mud weight less than pore pressure (PP), (2) losses prevention, and (3) wellbore stability control. Lastly, it will provide a case history illustrating how MPC was used in one of the operator's mature fields, by giving an overview of the job engineering design process, the operational planning (inclusive of contingencies), and the key highlights and learnings observed during execution.