Shell Offshore Inc. and partners will install the Gulf of Mexico's third tension leg platform (TLP) in a $1 billion campaign to jointly develop the Ram-Powell deepwater prospect.
Installation of the Ram-Powell TLP in mid-1997 in 3,218 ft of water on Viosca Knoll Block 956 will set another Shell water depth record for U.S. oil and gas development. Production is to begin in late 1997, with cumulative gross recovery expected to amount to about 250 million bbl of oil equivalent. A 50:1 gas:oil ratio is expected.
Shell last April claimed the current U.S. water depth record for offshore production when its started up its Auger TLP in 2,860 ft of water on Garden Banks Block 426. That record will be eclipsed in 1996 when Shell and BP Exploration Inc. install their Mars TLP in 2,933 ft of water on Mississippi Canyon Block 807.
Operator Shell holds a 38% interest in Ram-Powell development and Amoco Production Co. and Exxon Co. U.S.A. 31% each.
The eight tract Ram-Powell unit, approved by the Minerals Management Service in June 1989, covers Viosca Knoll Blocks 867, 868, 911, 912, 913, 955, 956, and 957. The unit is about 125 miles east-southeast of New Orleans and 80 miles south of Mobile, Ala., in 2,000-4,000 ft of water.
Shell owns 100% interests in Blocks 867, 911, and 912. Amoco and Exxon each hold 50% interests in Blocks 868, 913, 955, 956, and 957.
RAM-POWELL DETAILS
Shell drilled the Ram-Powell discovery well in May 1985 on Viosca Knoll 912 using the Discoverer Seven Seas drillship. During 1985-89, Shell, Amoco, and Exxon drilled 12 more exploratory and delineation wells, including one that was production tested.
Partners have logged five potentially commercial pays at 5,500-13,500 ft.
Ram-Powell's wells are to be laid out on the seabed in a 60 by 80 ft rectangular pattern. The number of wells needed to fully develop the field is to be decided after production begins.
Partners beginning in late 1995 before TLP installation plan to predrill three or four development wells. A contract platform rig equipped with a surface blowout preventer and high pressure drilling riser will drill more wells from the TLP after installation.
Also, as many as four subsea wells are to be drilled and tied back to the TLP.
Development is to include horizontal holes and large diameter completions using 4 1/2 in. production tubing. Drilling contractors for the various wellbores have not been chosen.
Ram-Powell production is to be shipped about 25 miles by pipeline to fixed platforms in relatively shallow water on the gulf's Outer Continental Shelf. Oil is to move through a 12 in. subsea line and gas through a 14 in. line. Construction of the pipelines is to begin in 1996 by a contractor to be chosen this year.
RECORD SETTING TLP
The Ram-Powell TLP is to be similar in design and size to the Mars TLP, weighing about 41,000 tons and standing 3,570 ft high from the seabed to the crown block of the rig when fully installed.
Ram-Powell TLP's deck is to be 245 by 245 ft wide and 40 ft high, weigh 19,500 tons, and include wellbay, quarters, processing, power, and drilling modules.
TLP drilling and production topsides will have slots for as many as 20 wells. Production equipment is to have capacity to separate, dehydrate, and treat as much as 60,000 b/d of oil, 200 MMcfd of gas, and 30,000 b/d of produced water. McDermott International Inc. is to fabricate Ram-Powell TLP's deck starting next month in Morgan City, La.
Ram-Powell TLP's 17,000 ton hull is to be composed of four 165 ft high, 66 1/2 ft diameter circular steel columns and a 27 ft wide, 24 1/2 ft high ring pontoon with a rectangular cross section. Belleli SpA will fabricate the hull at Taranto, Italy.
The TLP is to have twelve 3,145 ft long tendons - three on each corner - each with a diameter of 28 in. and 1.2 in. W.T. Each tendon is to weigh about 10,000 tons.
Ram-Powell TLP's foundation system will consist of 12 piles to which the tendons will be attached by means of tendon receptacles. Each pile is to be 365 ft long and 84 in. wide and weigh 225 tons.