Rig Optimisation for Energy Efficiency and Emissions Reduction for Well Plug and Abandonment

Decommissioning wells in the North Sea is a significant challenge, with around 2,100 wells needing plug and abandonment (P&A) over the next decade. Conventional P&A operations are energy-intensive and costly, especially in the North Sea, where semi-submersible rigs are common. These rigs, essential for deep water and harsh environments, consume substantial energy due to diesel-electric systems and dynamic positioning, increasing their carbon footprint. This paper explores strategies to optimize rig operations, enhancing energy efficiency and reducing emissions. A data-driven optimization model was developed to analyse energy efficiency and emissions reduction taking into consideration economic and environmental factors. The results show that allocating 5% of funding to rig upgrades can achieve a 7% improvement in energy efficiency and a 4% reduction in emissions. The optimal solution combines the installation of hull coatings to reduce drag and waste heat recovery for heating purposes. These findings demonstrate that rig optimization and technological upgrades can make the rig-based approach more sustainable and cost-effective in the long term for well decommissioning.