Pioneering Perforation, Wash and Bismuth Plug for Groundbreaking Revolution and Decommissioning and Abandonment

Abstract This paper presents the first Plug and Abandonment (P&A) operation in Malaysia that utilized Bismuth Alloy as an innovative abandonment material. The operator employed a novel approach by placing the Bismuth Alloy Barrier not within a milled window, but rather in the annulus against the formation through perforations that had been meticulously washed to remove the original cement. The choice of Bismuth Alloy P&A barrier over conventional materials was motivated by the desire for a more efficient and compact solution. The Bismuth Alloy barrier, requiring only 6 feet in length, provides superior integrity compared to a standard 120-foot conventional P&A barrier. This significant reduction in length enabled the operator to create a shorter window, a strategic advantage given the milling efficiency limitations of the hydraulic workover rig used for the P&A operations. The operator further innovated by replacing the planned 20-foot section milled window with a 6.2-foot casing perforation run, followed by precise cement removal using high-efficiency washing techniques. Subsequently, three Bismuth Alloy plugs were installed across the zone, marking a paradigm shift in operational methodology. Firstly, this paper highlights the distinctive sealing mechanism of Bismuth Alloy, demonstrating how its expansive forces during the solidification process provide enduring benefits as a P&A barrier. Secondly, the paper delves into the business case for Bismuth Alloy P&A, contrasting the conventional approach with the innovative Bismuth Alloy P&A method featuring a shorter 20-foot section milled window, and ultimately introducing the groundbreaking 6-foot Perf Wash Bismuth P&A. This evolution represents a significant leap in P&A operational efficiency, resulting in reduced rig time, lower Health, Safety, and Environment (HSE) and operational Non-Productive Time (NPT) exposure, decreased emissions, and, most importantly, enhanced barrier integrity. Thirdly, the paper details the comprehensive Perf Wash Bismuth business process. This innovative system involved the installation of three Bismuth Alloy Plugs, covering the 13-3/8" perforated casing wellbore and the 13-3/8" × 18-1/2" open hole annulus. The results illustrate a transformative approach to P&A operations, underscoring the efficacy and benefits of utilizing Bismuth Alloy in well abandonment. This pioneering operation in Malaysia sets a new standard for future P&A projects, emphasizing the importance of adopting advanced materials and techniques to achieve optimal well integrity and environmental safety.