The abandonment and decommissioning of Chinguetti and Banda fields located off the coast of the Islamic Republic of Mauritania are currently underway. Chinguetti, an oil-producing field, was Mauritania’s first deepwater field development, while Banda contained gas resources.
Discovered in 2001, the Chinguetti field entered into commercial operations in 2006 and witnessed a peak production of 75,000 barrels of oil per day (bopd) for a brief period before it rapidly fell to 15,000bopd in 2007 and to 7,000bopd in 2013 due to unexpected reservoir discontinuity issues.
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The decommissioning of the Chinguetti was undertaken after it reached the end of its economic life. Production was ceased from the field in December 2017 and the phased decommissioning commenced in 2018.
The Chinguetti field was operated by Woodside until Petronas Australia took over the field in December 2007.
Petronas Carigali Mauritania 1 (PCMPL), a wholly-owned subsidiary of Petronas, was the operator of the field, while Tullow Oil, Mauritania’s oil company Société Mauritanienne Des Hydrocarbures et de Patrimoine Minier (SMHPM), Premier, Kufpec were its partners.
The Banda gas field was discovered in 2002 and a decision to abandon the field was taken by the project partners after shelving plans to go ahead with its development. Tullow Oil was the operator of the field.
Location
The Chinguetti oil field is located in Block 4, production sharing contract (PSC) area B, about 80km southwest of Nouakchott, offshore Mauritania. The water depth in the field area is approximately 800m.
The Banda gas field is located in PSC A and PSC B, 20km to the east of the Chinguetti field, offshore Mauritania. It is approximately 55km from the coastline.
Chinguetti and Banda fields development details
The Chinguetti field development consisted of 15 subsea and water injection wells, subsea manifolds, flowlines and risers connected to a permanently turret-moored floating production, storage and offloading (FPSO) vessel, the Berge-Helene, operated by BW Offshore.
Built in France in 1976, the FPSO had a production capacity of 75,000 barrels per day (bpd) and a storage capacity of 2,000,000 barrels. The 372m long and 52m wide vessel was also used to deliver the associated gas and seawater to the gas and water injection wells. Crude oil produced by the FPSO was transported through oil tankers.
The Banda field was appraised by Woodside and Petronas before Tullow acquired the operatorship of the field in November 2011.
The development was planned to include the drilling and installation of two gas production wells, connected to an onshore gas processing facility, located about 9km to the north of the city of Nouakchott, through a sub-sea pipeline. The processed gas was proposed to be supplied to a new power generation project in Mauritania.
Chinguetti and Banda’s decommissioning details
The Chinguetti oil field decommissioning was planned to be carried out in two phases with the ceasing of production and temporary well suspension in the first phase, and final plugging and abandonment of the well stock in the second.
Phase 1 was completed in 2018 and resulted in eliminating hydrate blockages in the subsea system and 10 wells while they were being shut down.
The decommissioning project also involved disconnection, laydown and wet storage of flexible risers, umbilical and mooring lines from the Berge Helene FPSO.
The Banda abandonment project covers the plugging and abandoning of the subsea wells that were drilled to develop the gas field.
Contracts awarded
Havfram (previously Ocean Installer) was contracted by PC Mauritania 1 to deliver engineering, procurement, retrieval and disposal (EPRD) services for the abandonment and decommissioning of subsea facilities at Chinguetti and Banda fields in May 2022. The contract scope consisted of the retrieval and disposal of the remaining field infrastructure. The company was also selected for phase 1 decommissioning operations of the Chinguetti field in 2018.
Petrofac was awarded a contract by Tullow Oil for project management, engineering, planning and plugging and abandonment (P&A) of subsea wells on the Banda field in May 2022. The contract involved taking over the execution of the subsea well decommissioning scope from Maersk Decom and providing personnel, assets and equipment for the project.
Expro was contracted for the well intervention scope of the Chinguetti field phase II decommissioning project. The contract involved the delivery of a subsea well access system, umbilicals, surface flowhead, topsides control equipment and installation and intervention workover control system (IWOCS) package.
Ocean Installer was awarded a contract by Petronas for the decommissioning of risers and umbilicals on the Chinguetti field. The company was also contracted by BW Offshore for the decommissioning of the Berge Helene FPSO in February 2018.
PDi was selected for a revised comparative assessment of various decommissioning scenarios for the subsea facilities at Chinguetti and Banda.
Reservoir Link was awarded a contract by PC Mauritania to provide perforation and wash for abandonment and decommissioning of Chinguetti and Banda fields.
MacAlister & Elliott & Partners was contracted to prepare an environmental impact statement, waste management plan and fisheries impact assessment for the Chinguetti oil field facilities as part of the abandonment and decommissioning project.
