The Usan Oil Field is located approximately 100 kilometers off the coast of the Niger Delta in Nigeria, specifically in licence block OML 138 (also referred to as OPL 222).
The field is situated in water depths ranging from 750 to 850 meters.
Discovery and Development
The Usan field was discovered in 2002. Subsequent appraisal wells, including Usan-2, Usan-3, Usan-4, Usan-5, and Usan-6, further defined the field's extent and potential.
In 2005, the eastern extension of the Usan field was confirmed by wells Usan-7 and Usan-8.
Development approval was granted by the Nigerian Government in February 2008.
Operator and Partners
The field is operated by Total E&P Nigeria Limited, a wholly-owned subsidiary of TotalEnergies.
The partners in the project include:
TotalEnergies: 20% interest
Chevron Petroleum Nigeria Ltd.: 30% interest
Esso Exploration and Production Nigeria (Offshore East) Ltd.: 30% interest
China National Petroleum Corporation (CNPC), which acquired a 20% interest from Total in 2012.
Production and Reserves
The field began production in February 2012.
The estimated proven and probable reserves of the Usan field are in excess of 500 million barrels of oil.
As of 2022, the remaining recoverable reserves were estimated at 184.9 million barrels of crude oil and condensate.
Production Capacity and Infrastructure
The development involves 23 subsea production wells and 19 water and gas injection wells connected to a Floating Production, Storage, and Offloading (FPSO) vessel.
The FPSO, built by Hyundai Heavy Industries (HHI), measures 320 meters in length, 61 meters in width, and weighs approximately 116,000 metric tons. It has a storage capacity of 2 million barrels of oil and a maximum daily production capacity of 180,000 barrels of crude oil.
The FPSO also processes 5 million cubic meters per day (176.6 million cubic feet per day) of gas, which is primarily re-injected into the reservoir to minimize gas flaring.
Contractors and Subcontractors
Hyundai Heavy Industries (HHI): Constructed the FPSO on a turnkey basis, including engineering, procurement, and construction.
Saipem: Responsible for the engineering, procurement, construction, installation, pre-commissioning, and assistance to commissioning and start-up of the subsea umbilicals, flowlines, risers, and the oil loading terminal. They also handled part of the FPSO anchoring system.
Acergy: Fabricated, assembled, and tested subsea structures including manifolds, suction piles, and well jumpers at their Globestar Yard in Warri, Nigeria.
Nexans: Supplied umbilicals and associated equipment, as well as power, control, instrumentation, and telecommunications cables for the FPSO.
Cameron: Provided subsea systems, including subsea Xmas trees, production and intervention control systems, manifolds, and flowline connection systems.
Local Content and Environmental Impact
The project involved a significant level of local content, with over 500,000 engineering man-hours and 14 million construction and installation man-hours performed in Nigeria. The FPSO construction included the offshore integration of 3,500 tons of locally fabricated structures.
Total introduced technological innovations to reduce gas flaring, minimizing the project’s environmental impact. Large-scale training and capacity-building programs were also implemented to enhance the skills of the local workforce.
Historical Milestones
2002: Usan Oil field discovered.
2005: Western extension discovered.
2008: Development approval given for the Usan Project; Acergy awarded fabrication contract for subsea structures; HHI began building the FPSO.
2009: West Capella drilling rig positioned at the field.
2010: FPSO launched in November.
2011: FPSO arrived at the field in July.
2012: First oil produced in February; Total announces sale of 20% stake to Sinopec.