Na Kika Oil and Gas Fields, United States of America
The Na Kika field extends over Missisipi Canyon blocks 474, 429, 657, 607, 522, 520, 383 in the Gulf of Mexico, approximately 140 miles south-east of New Orleans, Louisiana, US. It has recoverable reserves of 300 million barrels of oil equivalent and a production rate of around 110,000bpd oil and 500 million cubic feet of gas a day.
It originally consisted of five independent oil and gas fields – Kepler, Ariel, Fourier, Herschel and E Anstey. Wells drilled on the Coulomb gas field were subsequently added. The water depths range from 1,770m to 2,360m, making it the deepest subsea cluster in the world.
The field was completed as subsea developments tied back to a centrally-located, permanently moored floating host facility, designed to process oil and gas from ten satellite subsea wells. Na Kika is named after the Polynesian God of the Octopus. The layout resembles an octopus body (host platform) and the tentacles (the infield flowlines to the six subsea fields).
During the development phase, the field was operated by Shell, which was responsible for the design, fabrication and installation of the floating host facility as well as the subsea production system. The company also drilled the first ten development wells. Upon production, operatorship reverted to BP, which is responsible for the operation of the platform and satellites.
Shell has a 50% interest in the floating host facilities and the Kepler, Ariel, Fourier, and Herschel fields, with BP having the remaining 50% interest. Shell has a 37.5% interest in the East Anstey field, with BP holding the remaining 62.5%. The Kepler, Ariel and Herschel fields are primarily oil, while the Fourier and East Anstey fields are primarily gas.
Development drilling was carried out in September 2001 – June 2002 using the Transocean Marianas – at the time marking the deepest water depth for any development well. The wells were completed between June 2002 and February 2003.
The project marked the first deepwater subsea well completion with three commingled reservoirs, and the first deepwater subsea well using SMART technology to provide intelligent completions in the multizone wells.
The subsea systems consist of satellite oil wells flowing through insulated pipe-in-pipe flowlines and gas wells flowing through uninsulated flowlines. The subsea trees and jumpers were supplied by FMC.
Shell awarded Coflexip Stena Offshore (now Technip), the infield flowlines contract. It used the CSO Deep Blue to carry out the deepest ever pipe-in-pipe system using J-lay and the deepest ever fully reeled Steel Catenary Risers (SCR).
The north oil loop consists of 29 miles of 10in-inside-16in pipe-in-pipe flowlines which were J-laid, while the 26-mile long south oil loop of 8in inside 12in pipe-in-pipe was reeled. The 32-mile long south gas loop consists of 8in uninsulated lines which was also reeled.
In late 2007 and early 2008, two wells were added to the existing Na Kika fields. The Isabela discovery is expected to be tied back to Nakika field in 2011.
In June 2009, ClampOn, a supplier of sand monitoring for Shell, secured the order for various subsea sand monitors and pig detectors for the Isabela field.
Development in 6,500ft (1,980m) of water will come on-stream in the first quarter of 2011 through tieback to the Na Kika field. ClampOn has supplied acoustic subsea sensors with atmospheric and high-pressure chambers, pipe contact verification, electronic beam welding and dual independent electronics.
The semi-submersible platform is based on four square steel columns, 56ft wide and 142ft high, connected by four rectangular steel pontoons, 41ft wide and 35ft high.
The hull was designed by ABB Lumus Global and fabricated by Hyundai Heavy Industries (HHI), Ulsan, South Korea. It weighs 20,000t and provides 64,000t of displacement. The topside facilities measure 335ft by 290ft, with a 130ft by 120ft central opening.
The topsides were designed by DCA. It was based on four modules – quarters for 60 people, process, east receiving and west receiving – totalling 20,000t. There are complete separation, dehydration and treatment facilities.
The production systems feature an advanced slug control (gas lift, surface slug suppression device, automated process controls, dynamic modelling), a coiled tubing gas lift for start-up and production enhancement and an enhanced produced water treatment.
The host platform is secured by a 16-leg catenary mooring system comprising suction piles supplied by McDermott, and a chain and wire rope line extending a distance of 6,600ft to 8,300ft from the platform location. The mooring system was supplied by Heerema Marine Contractors with Vicinay providing the mooring chain and shackles.
The wellstream was exported via an 18in diameter oil pipeline and a 20in diameter natural gas pipeline. The export pipelines were installed by Allseas.
BP / Shell commissioned a 75-mile Na Kika segment of the Okeanos Gas Gathering System from Na Kika to Main Pass 260. From here, the gas is transported to onshore markets via the BP / Shell Destin pipeline system.
A sixth field, Coulomb, (100% Shell) lies in Mississippi Canyon Block 657 in a water depth of approximately 7,600ft. It is approximately 25 miles east of the Na Kika production host facilities.
The discovery well and sidetrack were drilled in 1988 and the appraisal well and sidetrack were drilled in 2000.
Primarily a gas well, Coulomb has produced back to the Na Kika production host facility using a subsea production system consisting of one or two wells. Production started in 2005.