One Run, One Plug: A New Modular P&A Strategy for Faster, Safer, and Cost-Effective Abandonment

Abstract Objectives / Scope This paper presents an innovative methodology for Plug and Abandonment (P&A) operations that significantly enhances efficiency, safety, and cost-effectiveness through the use of a modular single-trip cement plug placement system. The approach introduces a novel combination of a quick-disconnect tool, inflatable packer, dedicated circulation sub and sacrificial string, all deployed as a single bottom-hole assembly, enabling placement of long, tailored cement plugs in a single operation. This contrasts with conventional P&A practices, which often rely on multiple stacked cement plugs and require several dedicated trips (for placement and for tagging) leading to increased operational complexity, higher costs, and extended rig time. Methods, Procedures, Process The new methodology addresses these limitations by introducing modularity and design flexibility into cement plug placement customized for each well scenario. The inflatable packer provides a secure and firm mechanical base at a pre-determined depth, while the circulation sub and disconnect tool allow precise plug placement, simplified release from the work string, usage of old and rejected pipes as sacrificial string instead of sent for disposal. This configuration minimizes risks associated with traditional methods, such as plug integrity, Equivalent Circulating Density (ECD) constraints and potential formation losses, particularly in wells with weak or fractured zones. Results, Observations, Conclusions Field trials of this approach were conducted across multiple offshore wells in both West Africa and the Americas. In West Africa, the quick-disconnect tool was tested as a standalone system during the permanent abandonment of a 12-1/4-in. open hole. Here, 400-meter-long cement plugs were successfully placed in a single operation, replacing the conventional approach of placing two 200-meter plugs in sequence. This not only fulfilled regulatory isolation requirements but also demonstrated the tool's reliability and allowed operators to gain familiarity with its use. The trial resulted in operational simplification and an estimated cost savings of USD 1.5 million. In the Americas, the full system—including the inflatable packer, circulation sub, and disconnect tool—was deployed in a single run for the abandonment of an 8-1/2-in. open hole. The plug base was set approximately 600 meters above the well's total depth. The entire system was assembled on a 3-1/2-in. sacrificial tubing string and deployed in one trip. The result was a successful cementing operation with no requirement to pull out of the cement, further reducing rig time and improving service quality. This operation was also completed ahead of schedule, again resulting in an estimated cost saving of USD 1.5 million. The success of these operations demonstrates the robustness and adaptability of the system. The modularity allows for flexible plug designs tailored to specific well conditions and regulatory demands, including control over hydrostatic pressure and gas migration. The system eliminates the need for staged operations and multiple trips, directly contributing to reduced operational risk, rig time, and cost. Novel / Additive Information In conclusion, this innovative approach to P&A operations represents a major advancement in well abandonment practices. By combining modular design with efficient deployment, the methodology enables safer, faster, and more cost-effective operations. Its field-proven success indicates significant potential for broader application across a variety of well types and abandonment scenarios globally.