Eni’s West Hub Development Project involves the initial development of the Sangos, Cinguvu and Mpungi fields, as well as the subsequent development of the Mpungi North, Vandumbu and Ochigufu fields in later stages. The deepwater offshore oilfields are located in Block 15/06 at water depths ranging from 1,000m to 1,500m. Block 15/06 is located approximately 350km north-west of Luanda, Angola, and covers approximately 2,984km².
As the operator of the block, Eni holds a 35% interest, while the remaining partners in the block include Sonangol (35%), SSI (a joint affiliate of Sinopec and Sonangol, 25%) and Falcon Oil Angola Investimentos (5%). Total sold its share of a 15% interest in the field to Sonangol for $750m in February 2014. The block was earlier awarded to the partners during Angola’s 2006 licensing round.
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Production from the Sangos field was achieved in November 2014 and the Cinguvu oil field came on-stream in April 2015. The two fields are currently producing 60,000 barrels of oil per day (bpd). The Mpungi field came online in January 2016, bringing the total production to 100,000bopd by the first quarter of 2016.
Discovery and geology
Sangos field was discovered in May 2008 by drilling the Sangos 1 exploration well to a total depth of 3,343m. The well confirmed a significant presence of more than 30º API gravity oil.
Ngoma field was discovered in October 2008 by drilling the Ngoma-1 well to a total depth of 3,383m. It confirmed the presence of 22.5º API gravity oil.
Cinguvu field was discovered in April 2010 by drilling the Cinguvu-1 well to a total depth of 1,400m. Oil flowed at a maximum rate of 6,400bpd.
Mpungi field was discovered in October 2010 by drilling the Mpungi 1 well to a total depth of 2,300m. The well flowed light oil at rates of more than 6,000bpd during the production test.
Vandumbu field was discovered in March 2013 by drilling the Vandumbu well to a total depth of 4,107m. An additional sidetrack well, Vandumbu 1 ST, was drilled to a total depth of 3,480m, which is expected to be capable of producing more than 5,000bpd.
Oil reserves within the block are located in the Miocene sand reservoirs.
Development details
Phase I of the West Hub project involved the drilling of 21 subsea wells, which include 12 production and nine injection wells that are tied back through subsea facilities to the host platform FPSO N’Goma (formerly known as FPSO Xikomba).
Later stages will involve the drilling of two producer wells and an injection well at the Vandumbu field, as well as a producer well and an injection well at the Mpungi North field. The fields will also be connected to the same FPSO.
FPSO N’Goma
FPSO N’Goma was upgraded and refurbished from FPSO Xikomba, which earlier served at the Angola Block 15 operated by ExxonMobil. It involved the life extension, refurbishment and upgradation of existing topside modules and turret mooring system, including the installation and integration of a new sulphate removal package and hot oil pump topside modules.
The FPSO is owned by Sonasing, a joint-venture (JV) comprising SBM Offshore, Sonangol and Angolan Offshore Services. It is operated by OPS and leased to Eni for a period of 12 years.
Keppel Shipyard refurbished the topsides and performed upgrade work on the hull and turret. The FPSO was later transported from Singapore to Paenal shipyard in Port Amboim, Angola, where the new topside modules were further integrated with the FPSO in June 2014. It was christened in July 2014 at the Paenel Shipyard, and is now at the project site.
FPSO N’Goma has a total storage capacity of around 1.5 million barrels, oil processing capacity of 100,000bpd, gas handling capacity of 115 million standard cubic feet a day and water injection capacity of 120,000bpd.
Contractors involved
Engineering, procurement, fabrication and installation of the rigid and flexible flowlines, risers and umbilicals were performed by Technip under a contract worth $1bn. Technip’s Deep Energy and Deep Pioneer vessels were involved in the installation work.
Up to 34km of static and dynamic steel tube umbilicals for the project were supplied by Aker Solutions under a Nkr300m ($50m) contract .
Veolia Water Solutions & Technologies supplied a module seawater sulphate reduction package (SRP) system for the FPSO, with a capacity of 117,455bpd and an integrated Dow Filmtec seawater reverse osmosis (SWRO) system with a capacity of 12,075bpd.
