Kerr McGee’s Constitution field is located in Green Canyon blocks 679 and 680, approximately 190 miles southwest of New Orleans in the Gulf of Mexico. The field has estimated proven and probable resources of approximately 110 million barrels of oil equivalent.
The development is based on spar technology. Moored in 4,970ft of water, the spar will initially handle production from the Constitution field and the tied-back Ticonderoga field. The total project costs have been put at around $600 million. Kerr-McGee holds a 100% interest in Constitution and a 50% working interest in Ticonderoga with Noble Energy accounting for the remaining 50%.
CONSTITUTION FIELD APPRAISAL
Constitution was appraised by drilling 11 wells into predominantly oil-bearing sands in seven reservoirs. These have an average porosity of 28%, permeability of 800 millidarcies and 32ºAPI gravity. The Pliocene reservoirs are located at depths from 12,500ft to 15,000ft. The development plan for the Constitution field includes five dry trees and one subsea tieback. Previously drilled appraisal wells will be re-employed as part of the final development plan.
CONSTITUTION SPAR DESIGN
The Constitution spar design is based on the Kerr McGee’s Gunnison model to reduce costs and lead times. This has topsides capable of processing 40,000bd of oil and 200MMcfd of gas. The hull is 98ft in diameter and approximately 550ft long. The spar has a 113ft by 159ft workover deck, a 127ft by 162.5ft main deck and a 127ft by 176ft cellar deck. The hull weighs 14,800t and it supports a 10,770t topside payload. It was built by Technip at its Pori, Finland yard. It was then transported to the Gulf Marine Fabricators yard in Ingleside on the Mighty Servant 3.
OIL AND GAS PIPELINES
Oil export will centre around a 70 mile, 14in and 16in pipeline system linking it to the Ship Shoal 332B platform, 75 miles south of the Louisiana coastline. There, it tees into the 390 mile, 500,000b/d Cameron Highway oil pipeline. The 30in diameter pipeline segment runs west 113 miles from Ship Shoal 332B along the outer continental shelf to GulfTerra’s Garden Banks 72 hub. From there, it goes northwest to the new High Island A-5 platform, from which two 24in pipeline segments will deliver oil to multiple delivery points in Texas City and Port Arthur, Texas.
The gas is exported through a 35 mile, 14in and 16in pipeline to a subsea interconnect on Green Canyon block 241 for the Anaconda pipeline that connects the Marco Polo platform with a platform on Eugene Island block 371.
Ticonderoga will be tied back to Constitution. The field lies in salt mini-basin with hydrocarbons located around the rim. Kerr-McGee has identified seven different hydrocarbon zones in the field. One fault block in the field contains gas while the remaining fault blocks contain oil. With stacked Pliocene reservoirs at a 12,000ft to 15,000ft depth, the initial well encountered more than 100ft of net oil and the second well had more than 350ft.
The project covers the installation of two pipe-in-pipe flowlines and steel catenary risers along with Pipeline End Termination (PLET) structures for the tie-back of the wells.
Technip won the subsea flowline installation contract, using the deepwater pipelay vessel Deep Blue to install the flowlines. Following first production in mid-2006, the two wells’ development will reach 40,000b/d and 75MMcfd in 2007.