Ram-Powell Tension Leg Platform

The blocks are located in the Gulf of Mexico approximately 125 miles east, southeast of New Orleans and approximately 80 miles south of Mobile, Alabama, in water depths ranging from 2,000 to 4,000 feet. The leases were acquired in 1984, 1986, 1987 and 1988.
 

Shell Deepwater Production Inc. is the operator and has a 38% interest in the project. BP and Exxon/Mobil each have a 31% interest.
 
Shell leases Viosca Knoll Blocks 867, 911, and 912. BP and Exxon/Mobil share 50-50% Viosca Knoll Blocks 955, 956, 957, 913 and 868. The discovery well was drilled on Viosca Knoll Block 912 in May 1985 using the Transocean drillship Discoverer Seven Seas.
 
Between 1985 and 1989, Shell, Amoco and Exxon drilled 12 exploratory wells from five surface locations, including one production test. Five potentially commercial pay sands have been logged between 5,500 and 13,500 feet subsea.

Development Plans
Shell announced in January 1995 the partners' plans to develop Ram-Powell utilizing a tension leg platform (TLP) to be installed on Block 956 in 3,214 feet of water. It surpassed the depth record in the Gulf of Mexico for a permanent drilling and production platform - Shell/BP Amoco's Mars TLP - which was installed in 2,940 feet of water in 1996.
 
API gravity is 33 degrees; sulphur content is between 0.25% and 0.45%.
 
TLP fabrication began in January 1995. Four of the planned development wells from the 20-slot TLP were predrilled using the Transocean Rather beginning in the third quarter of 1996. A total of 10 development wells have been drilled from the TLP using the Helmrich & Payne contract platform rig H&P 202.
 
Development wells include application of large-bore (5.5" tubing) and horizontal well completions. There are five horizontal open hole gravel pack wells in single reservoirs and five conventional gravel pack wells using multiple zone production capability. The TLP was installed in May 1997.

Production
Production began in September 1997.

Production from the platform is transported approximately 25 miles via a 12-inch diameter oil pipeline to Main Pass 289C and a 14-inch gas pipeline to Viosca Knoll 817. Both pipelines were installed as part of the Ram-Powell development.

TLP Engineering/Construction Details
The Ram-Powell TLP was designed and engineered by a joint partner team made up of personnel from Shell, Amoco and Exxon, with support from outside contractors in Louisiana and Texas.
 
Completely assembled, the TLP is 3,570 feet high, from seafloor to the crown block of the drilling rig and its steel weight is approximately 41,000 tons. It has been designed to simultaneously withstand hurricane force waves and winds.
 
Hull 
Weighing around 15,000 tons, the hull is comprised of four circular steel columns, 66.5 feet in diameter and 165 feet high, and a ring pontoon 27 feet wide and 24.5 feet high, with a rectangular cross section. Fabrication of the hull was completed in October 1996 by Belleli S.p.A. in Taranto, Italy, and the hull arrived in the Aker Gulf Marine yard near Corpus Christi, TX, in November 1996.
 
Deck 
An open truss/deep girder design, 245 feet x 245 feet x 40 feet high, and weighing approximately 8,100 tons, the deck is composed of five modules: wellbay, quarters, process, power and drilling. McDermott International, Inc. in Morgan City, LA, built the modules. The first module was loaded out on November 6th with shipment of the remaining modules concluded by the end of December 1996.
 
Tendons/Piles 
There are 12 tendons, three per corner, each with a diameter of 28 inches and a wall thickness of 1.2 inches. Each is approximately 3,145 feet long, and the total weight for the 12 tendons is approximately 10,000 tons. The TLP foundation system is comprised of 12 piles to which the tendons are attached by means of tendon receptacles. The piles are 84 inches in diameter and 349 feet long, weighing approximately 270 tons each. Aker Gulf Marine built the tendons and piles in Corpus Christi, TX.

Drilling and Production Topsides 
There are 20 well slots, and the well layout on the seafloor is arranged in a rectangular pattern approximately 60 feet x 80 feet.
 

The TLP supports a single modified API platform-type drilling rig (leased), equipped with a surface BOP and high pressure drilling riser. The accommodation module houses up to 110 people, along with a control room and emergency response center.

Pipelines 
Ram-Powell's oil and gas are piped to platforms in shallow water. The gas is transported to Viosca Knoll 817 and the oil is transported to Main Pass 289C. The pipelines are 12 inches (oil) and 14 inches (gas) in diameter. Allseas laid the pipelines using the Lorelay.