Environmental and Economic Considerations for the Decommissioning of Oil and Gas Infrastructure in Nigeria

Abstract When offshore structures reach their end of life it becomes necessary to remove them and return the environment to its initial state. Generally, there are three options for decommissioning which are complete removal, leave in place, and partial removal. The choice of option takes into consideration, economic environmental, technical, safety, stakeholders, and regulatory factors. This work aims to critically evaluates the environmental, economic, and regulatory aspects of oil and gas facility decommissioning in Nigeria and assesses the feasibility of various strategies in minimizing environmental impact and decommissioning cost. Following best practices of the United Kingdom, a leading country that has decommissioned several offshore facilities, the study highlights the challenges and opportunities associated with the Nigeria environment. A systematic approach was employed to evaluate the strategies, utilizing both ranking systems and sensitivity analysis. The findings indicate that the choice of decommissioning strategy has multifaceted implications, necessitating a thorough evaluation process. The study also proposes establishing a "Decommissioning Fund" and offering tax incentives for decommissioning activities. Technological advancements such as modern bond logging techniques, rig less intervention equipment and innovative containment approaches is deemed crucial for cost reduction and enhancing efficiency of decommissioning process. Theoretical insights derived from this study offer a fresh perspective on decommissioning in the Oil and Gas sector, highlighting both its challenges and opportunities. Practical implications of the findings are also discussed, providing industry practitioners with actionable recommendations.