Okoro

  • Type: Rig
  • field
  • Latitude: 4.4040000
  • Longitude: 7.8000000

Location and Geology

  • The Okoro oil field is located 12 kilometers offshore in the southeastern Niger Delta, Nigeria, at a water depth of 46 feet in block OML 112.

Discovery and Exploration

  • The Okoro field was discovered in 1973 by Japan Petroleum through the Okoro-1 well, which encountered two oil-bearing sands in the Agbada Formation at depths ranging between 4,900 and 5,500 feet. The well was tested and recorded a flow rate of 1,500 barrels per day (bpd), proving the commercial viability of the field. An additional appraisal well, Okoro-2, was drilled in November 1974 to further confirm the presence of both reservoir sands.

Ownership and Operation

  • The block OML 112 was awarded to Amni International Petroleum Development Company in 1993. In 2006, Afren plc, a UK-based company, became the technical services provider and operator of the field, holding a 50% working interest. Amni International holds the remaining 50% interest.

Field Development

  • Afren drilled an appraisal well named Okoro-3 in October 2006, which confirmed the presence of hydrocarbons in the eastern extension of the field. A sidetrack well, Okoro-3 ST, was drilled to a depth of 6,870 feet and encountered 70 feet of net oil pay.
  • In January 2007, Afren submitted a field development plan (FDP) to the Government of Nigeria, which was approved in April 2007.
  • Development drilling began in January 2008 using Transocean’s GlobalSantaFe Adriatic VI jack-up rig. Initially, two production wells were drilled, followed by five more wells that were brought on-stream.

Production

  • The first production from the Okoro field commenced in June 2008. By June 2010, the field had produced 11.4 million barrels of oil and was producing at a rate of 16,000 bpd. Additional wells were planned to increase production volumes.
  • In later developments, the Okoro-14 development well was drilled from the Okoro main field wellhead platform to establish initial production from the Okoro East field. A sidetrack was also drilled in the existing Okoro-5 production well to access additional oil volumes.

Infrastructure

  • Wellhead Platform: The Okoro wellhead platform is a conductor-supported minimum offshore structure (CoSMOS) with nine slots. It features gas lift and water injection facilities and was fabricated at Compact Manifold & Energy Services yard in Lagos, Nigeria.
  • FPSO: The oil produced is exported to the Armada Perkasa FPSO (later renamed Princess Aweni), which is located 1 kilometer south of the field at a water depth of 13 meters. The FPSO can process 27,000 bpd and store 360,000 barrels of crude oil. It features an eight-point mooring system and is connected to the Okoro wellhead platform through flowlines and risers.

Flowlines and Risers

  • Oil and gas produced from the field are transported to the FPSO through 3 kilometers of flowlines, including 4-inch gas lift, 6-inch test lines, and 8-inch production flowlines, along with three double lazy wave risers. The flowlines are covered with mats to provide additional stability from waves and currents.

Contracts

  • UK-based UWG was awarded a $5.5 million contract to design, construct, and install the Okoro wellhead platform and topside processing facilities. Deepflex supplied the flowlines and risers for the field.

Current Status

  • As of recent reports, the Okoro field is in terminal decline. There is a focus on cost reductions, and loan repayments are a key issue. The field has undergone full field development, including the installation of a second wellhead platform.

Reserves and Production Profile

  • The Okoro field’s reserves are estimated at 25 million barrels of oil. The field has been producing since 2008, with production peaking and now in decline. The production profile includes various development wells and sidetracks to optimize oil recovery.

Economic and Regulatory Aspects

  • The project operates under a production sharing agreement governed by the Petroleum Industry Act in Nigeria. The economic analysis includes considerations of operating costs, sales contracts, and fiscal regulations.

In summary, the Okoro oil field is a significant shallow-water oil project off the coast of Nigeria, operated by Afren plc and Amni International Petroleum Development Company, with a complex infrastructure including a wellhead platform and an FPSO, and a production history that began in 2008.

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