Abstract
As global oil and gas reserves continue to deplete, and aging platforms near the end of their design and production life, the imperative for their removal, commonly referred to as decommissioning, becomes increasingly pronounced. This paper sheds light on a recent offshore decommissioning project in Malaysia, concluded in June 2023, which distinguishes itself through the pioneering reuse and refurbishment of the decommissioned topside for a new oil and gas development project by a different operator. Simultaneously, the substructures underwent complete removal from the site for onshore disposal.
The decommissioned platform, a three-legged conductor-supported structure installed by a jack-up rig, presented unique challenges in its removal. Located just 3.3 nautical miles (approximately 6.1 km) off the coast of Sarawak, Malaysia, the soft soil conditions rendered jack-up rig removal too risky, a lesson learned painfully during the initial platform installation. The shallow water depth of 10 meters MSL further constrained lifting vessel selection and associated marine spread, posing challenges in planning well plug and abandonment (P&A) activities and overall facilities removal. Additionally, the decommissioning methodologies for this ‘conductor-supported platform’ significantly deviated from those typical of wellhead platforms.
This paper provides a comprehensive account of the decommissioning process, addressing challenges across all phases, including well abandonment, pre-abandonment surveys, data gathering, engineering, decommissioning, structural removal and transfer, disposal, and final site clearance. The successful execution hinged on critical factors such as engineering studies, cutting tool selection, removal sequences, and vessel selections.
Beyond the technical hurdles, the paper explores the collaborative efforts of the Project Management Team and Malaysia's regulatory body in optimizing schedule and costs. It aims to engage and inform those interested in platform and facilities abandonment and decommissioning, guiding readers through the entire journey of platform facilities decommissioning and removal.
