Impact of Planning and Experience in Well Abandonment - Lessons Learned from Complex Well Abandonment in Bonga Deepwater Field

Abstract The abandonment of deepwater oil and gas fields has become increasingly prevalent over the past decade as these assets reach the end of their productive and economic life. The Bonga Deepwater Field stands as a notable example, having produced over one billion barrels of oil since its inception in 2005. With more than 70 wells consisting of oil producers and water injectors drilled, the field’s development strategy incorporated a robust abandonment plan, ensuring compliance with Shell standards and local regulatory requirements. Over the last four years, the Bonga wells delivery team successfully abandoned 26 wells across three Plug and Abandonment (P&A) campaigns. These operations presented unique challenges, including complex well configurations and complications from previous failed interventions, which left tools and wireline conveyance equipment downhole. Addressing these challenges required a combination of meticulous planning, innovative technological applications, and the integration of diverse expertise from the well delivery team and service partners. This paper underscores the critical impact of proactive planning and accumulated experience in the successful execution of complex well abandonment. By leveraging insights from earlier abandonment campaign operations and incorporating industry best practices, the team implemented comprehensive front-end engineering design (FEED), rigorous risk assessments, and tailored operational strategies. Advanced techniques such as blind back-out fishing methods, technologies including electric-line powered tools for debris removal, and downhole imaging systems were deployed to overcome significant barriers. Furthermore, collaborative workshops and an integrated team approach were instrumental in developing robust solutions and refining Standard Operating Procedures (SOPs) for complex well abandonment. The lessons learned from these campaigns highlight how careful planning and experience-driven strategies ensure operational success. The result was the safe, efficient, and cost-effective abandonment of wells, achieved within budget while maintaining strict adherence to regulatory requirements and process safety standards. This paper provides a detailed exploration of the planning, execution, and lessons learned, offering a framework for future complex well abandonment projects in deepwater environments.