Project Profile
Value: Undisclosed
Location: East Breaks area of the Gulf of Mexico
Start-up Year: February 2002
Peak production: 40,000 barrels of oil and 80 million cubic feet of gas
Water depth: 3,453 ft (Boomvang) 3,678 ft (Nansen)
The Nansen and Boomvang fields lie in the East Breaks area of the Gulf of Mexico, approx. 150 miles south of Houston. Nansen lies in East Breaks block 602 and Boomvang lies in blocks 642, 643 and 683. Nansen lies in 3,678ft of water, while Boomvang lies in 3,453ft .Anadarko operates the Boomvang field with a 30% working interest and the Nansen field with a 50% working interest, following its purchase of the former operator Kerr-McGee Corp. in 2006. The other partners in Boomvang are Shell (50%) and Devon Energy (20%). Marubeni holds the remaining 50% interest in the Nansen field. Nansen was discovered in October 1999, in 3,680ft of water, approx. eight miles east of the previously announced North Boomvang discovery. Successful drilling of Nansen No 8 well, on East Breaks 602, extended the field to the south. At Boomvang, a second rig was secured to concurrently drill a total of up to seven wells at North and East Boomvang.
In February 2002, Nansen achieved first production from the first of three subsea wells. Daily production from the Nansen field ramped up to a peak rate of about 40,000 barrels of oil and 80 million cubic feet of gas by the fourth quarter of 2002, as completion activities at the remaining nine dry tree wells were completed. Both Nansen and Boomvang are being developed by the world\'s first truss spars. Spars International was contracted to design the almost identical systems.The spar completions at Nansen and Boomvang consisted of 14 wells with an average completion time of 49 days.
The truss design replaces the lower cylindrical hull in order to reduce weight and cost. The open truss structure also reduces movement and three heavy plates enhance stability. The Spars are 543ft in length and weigh 17,000t each. Air chambers in the upper hull provide buoyancy for the floating structures. In 2005, Nansen former partner Devon Energy (50%) said a four-well recompletion programme had lifted net production by 13,000 boepd. Devon sold its Nansen stake to BP in 2009, but the UK supermajor, in turn, sold the field interest to Japanese conglomerate Marubeni in 2010.
Pipeline:
The main pipeline was subcontracted by Williams to Coflexip Stena. The company used its CSO Deep Blue newbuild. Cal Dive International installed infield flowlines using its reeled pipelay system deployed from the Sea Sorceress. Workscope covered the installation of approximately 100,000ft of 6in-diameter pipelines, five flexible production risers and 86,000ft of associated umbilicals, plus the jumpers and flying leads necessary to tie-in three subsea trees. Wellstream designed and supplied the 5.625in, 6,000psi flexible pipe production risers and tie-in jumpers for the project. The risers were installed in a catenary configuration, enabling the spars to be offset for future on-site drilling. Bridon supplied HDPE sheathing on the wire spiral strand to be used for the spar moorings.
Operators:
Boomvang field
Anadarko:: Operator with 30% interest
Shell : 50% interest
Devon Energy Corp.: 20% interest
Nansen field
Anadarko: Operator with 50% interest
Marubeni:: 50% interest
Contractors:
Williams: Constructed and operates the Seahawk Gathering System
Subcontractors:
Coflexip Stena: Main pipeline construction
Cal Dive International: Installation of infield flowlines
Workscope Projects Ltd: Installation of approximately 100,000ft of 6in-diameter pipelines, five flexible production risers and 86,000ft of associated umbilicals, plus the jumpers and flying leads necessary to tie-in three subsea trees
Wellstream: Design and supply of the 5.625in, 6,000psi flexible pipe production risers and tie-in jumpers for the project
Bridon: Supply of HDPE sheathing on the wire spiral strand to be used for the spar moorings
Operators:
Boomvang field
Kerr McGee: Operator with 30% interest
Shell (purchased by Enterprise): 50% interest
Ocean Energy: 20% interest
Nansen field
Kerr McGee: Operator with 50% interest
Ocean Energy: 50% interest
Contractors:
Williams: Constructed and operates the Seahawk Gathering System
Subcontractors:
Coflexip Stena: Main pipeline construction
Cal Dive International: Installation of infield flowlines
Workscope Projects Ltd: Installation of approximately 100,000ft of 6in-diameter pipelines, five flexible production risers and 86,000ft of associated umbilicals, plus the jumpers and flying leads necessary to tie-in three subsea trees
Wellstream: Design and supply of the 5.625in, 6,000psi flexible pipe production risers and tie-in jumpers for the project
Bridon: Supply of HDPE sheathing on the wire spiral strand to be used for the spar moorings