Challenges and Lessons Learnt on Waste Management and Disposal from Mauritania Deepwater Abandonment and Decommissioning Campaign

ABSTRACT

Abandonment and decommissioning activities of oil and gas assets had been on the increasing trend. As an activity of minimal to no economic value return, the investment into Abandonment and Decommissioning (A&D) should be properly strategized to ensure all objectives are met safely within available time and resources. This paper will discuss Operator's strategy in planning and handling waste from A&D activities of fifteen (15) deepwater subsea wells in Mauritania, West Africa. The approach of this A&D project at a remote location was done in two separate campaign instead of a single campaign based on technical and commercial evaluations performed by Operator. Subsea structures, Christmas trees, tubulars and others are expected to be retrieved and disposed according to local and international standard. In general, Operator are expecting two (2) type of waste which are nonhazardous waste and hazardous waste due to hydrocarbon or naturally occurring radioactive material (NORM) contamination. Due to the limitation of capable hazardous waste handling and disposal in country, Operator decided to export waste to identified facilities outside of country at the end of the project via sea-freight. Operator appointed one contractor to provide a full-service related to the waste management and disposal that covers field services and onshore services that includes radiological monitoring to identify NORM waste, labelling, packaging at offshore, onshore storage, transportation and logistics that include Trans-Frontier Shipment (TFS). The strategy of appointing one contractor for full service of waste management and disposal has promoted a single - point accountability to the contractor and this has enabled the objective been delivered effectively. COVID-19 pandemic posed a great challenge on cross-border logistic planning due to additional measure been imposed by receiving country. Furthermore, the new development of United Kingdom exiting European Union (BREXIT) also posed some level of uncertainty to the contractor to obtain relevant approvals for waste export. To reduce the amount of waste to be export, Operator continuously looking for and successfully found a local recycling facility that able to handle the non-hazardous waste while meeting local regulation, Operator's and industrial standard. All outlined strategy was proven to be effective for waste management in remote location, uncertainty on cross-border waste export challenge, as well as capitalizing on the limited local resources available. Copyright © 2021, Society of Petroleum Engineers