Spar planned for Perdido fields in deep gulf

Oct. 26, 2006
Shell Offshore Inc. and partners will install a production spar in what Shell says will be a world record water depth to develop three oil fields along the Perdido fold belt in the Gulf of Mexico.

By OGJ editors
HOUSTON, Oct. 26 -- Shell Offshore Inc. and partners will install a production spar in what Shell says will be a world record water depth to develop three oil fields along the Perdido fold belt in the Gulf of Mexico.

It will moor the regional direct-vertical-access spar in 8,000 ft of water to handle production from Great White, Tobago, and Silvertip fields in the Alaminos Canyon area (see map, OGJ, Sept. 25, 2006, p. 36). Production from other fields in the region can be tied in as processing capacity becomes available.

The spar will be able to handle production of 100,000 b/d of oil and 200 MMscfd of gas, expected to begin "at the turn of the decade," according to Shell. It will have subsea lifting or boosting to move produced fluids from the seafloor to topsides.

The common processing hub, on Alaminos Canyon Block 857 near the Great White discovery, will have a drilling a completion rig and will gather, process, and transport production from wet trees as far away as 30 miles. Pipelines from the facility will connect to undisclosed locations in Texas.

The area has water depths of 7,500-10,000 ft and a rugged seabed. Marvin Odum, Shell executive vice-president, EP Americas, said the project will initiate production from the gulf's Lower Tertiary play.

Shell will operate the hub, called Perdido Regional Host, with a 35% interest. Other interests are Chevron Corp., 37.5%, and BP PLC, 27.5%.

Shell also operates the fields identified for development, none of which have had production tests. The reservoirs have temperatures of 150-200º F. and pressures of 5,000-9,000 psi. They produce oil of 20-40º gravity.

Shell has drilled five wells in Great White field, discovered in 2002 by a well that reached 14,405 ft TVD in 8,009 ft of water. The most recent Great White well was spudded in March 2004.

Shell holds 33.34% interest in Great White, which is on Alaminos Canyon Blocks 812, 813, 814, 857, 900, and 901. Chevron and BP hold 33.33% each.

Tobago field lies in 9,600 ft of water on Alaminos Canyon 859. Unocal Corp. discovered it in 2004 with a well that reached 18,510 ft TD (OGJ, May 10, 2004, Newsletter). A sidetrack reached 18,425 ft. Tobago interests are Shell 32.5%, Chevron 57.5%, and Nexen 10%.

Chevron made the Silvertip discovery on Alaminos Canyon Block 815 with the AC 815 No. 1 well, drilled to 14,778 ft TD in 9,200 ft of water in August 2004. Chevron holds 60% and Shell, 40%.