Project Profile
Location: South East Nigeria, lock OML 112, Nigeria
Production: 14,600 bopd
Estimated oil in place: 130 million barrels
Water depth: 46ft
Discovery: 1973
The Okoro field lies at a water depth of 46ft in block OML 112, which is situated about 12km off the shore of Nigeria. The field was discovered in 1973 by Japan Petroleum with the Okoro-1 well. The well encountered oil in two zones in the Agbada Formation and was logged and tested. The Okoro-2 well was drilled in 1974 at the eastern extension of the field and was water wet. The field is covered by good quality 3D seismic data which was acquired by Mobil Corporation. The field\'s reserves are estimated at 25mmbbls of oil. Afren Energy Resources, a subsidiary of Afren plc, is the operator of the field and holds 50% working interest. Amni International Petroleum Development Company holds the remaining 50% interest. Okoro was discovered by the Okoro-1 well, which encountered two oil bearing sands in the Agbada Formation at depths ranging between 4,900ft and 5,500ft. The well was tested and recorded a flow rate of 1,500bpd proving the commercial viability of the field. Another appraisal well Okoro-2 was drilled in November 1974 further confirming the presence of both reservoir sands.
Afren became the operator of the field in 2006 and drilled an appraisal well named Okoro-3 in October 2006 using the Seadrill 7 jack-up rig. The vertical well was drilled to a depth of 6,500ft and confirmed the presence of hydrocarbons in the eastern extension of the field. In December 2006, the Okoro-3 sidetrack well was drilled to a depth of 6,870ft. The well encountered 70ft of net oil pay. In January 2007, Afren submitted a field development plan (FDP) for the field to the Government of Nigeria. The FDP was approved in April 2007. Development drilling for the field was started in January 2008. Transocean\'s GlobalSantaFe Adriatic VI jack-up rig was used to initially drill two production wells. Another five wells were drilled subsequently and brought on-stream.
In May 2008, the Okoro wellhead platform was installed at the field and connected to the FPSO through flowlines. First production from the field commenced in June 2008. In June 2010, the field produced 11.4mmbbls of oil. Two more wells are planned to be drilled in 2010 to increase the field\'s production volumes. Currently the field is producing at a rate of 16,000bpd. Oil produced by the Okoro wellhead platform is exported to the Armada Perkasa FPSO. The oil is transported onshore by export tankers. Oil and gas produced from the field is transported to the Armada Perkasa FPSO through 3km of 4in gas lift, 6in test line and 8in production flowlines, and three double lazy wave risers. The risers feature bend stiffeners at the FPSO hang-off and anchors to keep them in position. The flowlines are covered with mats to provide additional stability from waves and currents. The Okoro platform is a conductor-supported minimum offshore structure (CoSMOS). The topsides of the platform are supported by well conductors, eliminating the need for a steel jacket. The platform has nine slots and features gas lift and water injection facilities. Fabrication of the platform was carried out at Compact Manifold & Energy Services yard in Lagos, Nigeria.
Operators:
Afren PLC: Operator with 50% interest
Amni Petroleum: 50% interest
Contractors:
Bumi Armada: Providing FPSO unit
Mobil Corporation: Seismic data
Transocean: Drilling contractor
InterMoor: Contract to complete a top chain replacement project the Armada Perkasa FPSO offshore Nigeria. InterMoor’s crew completed top chain replacement of all ten mooring lines of the FPSO and uncrossing of two mooring lines. InterMoor provided engineering/procedure development, procurement, and offshore implementation.