Stolt Offshore Completes Platform Salvage
Stolt Offshore reported it has successfully completed the Eugene Island 275A platform salvage project for Total E&P USA, INC., in what is described as the first platform salvage using only mechanical cutting devices. The platform was located on OCS-G-0988, some 70 miles off the Louisiana coast in 180 ft. of water.
"Because of environmental and safety objectives, Total E&P USA asked Stolt to conduct the salvage operation without an arc being struck under water, using remotely operated tools as much as possible," said Allan Palmer, Stolt's regional manager of regional projects and operations in Houston. "At the request of Total E&P USA. and assisted by LoneStar Deepwater Consulting, we conducted an extensive testing program to qualify the tools for this job." Stolt Offshore located heavy duty cutting tools that could be modified or redesigned to be used remotely underwater. Before taking the tools offshore, the company tested them at its Port of Iberia location at New Iberia, La.. The remotely operated tools had to be able to sever 42 x 0.5-in. jacket legs with 39 x 0.75-in. grouted piles down to 8-in. diameter jacket members. Stolt also tested tools for stripping and cutting casings to get vertical access to the wells for further plugging. These modified and redesigned cutting tools allowed Stolt Offshore to perform the first platform removal project done using only remote cutting devices. The Stolt Offshore tool kit included • heavy-duty shears; • high pressure, abrasive cutters; • diamond wire cutters; • guillotine-type saws; and • a variety of remotely operated mechanical cutters.
One of the hydraulic shears used for the job produces 750,000 psi of cutting force. It had originally been designed to cut concrete piles and was modified for this big underwater project. Palmer said. The abandonment project began in August 2002. with original plans calling for the removal of the deck for disposal onshore and the transportation of the jacket to a nearby artificial reef site. In parallel, Stolt Offshore had commenced abandonment procedures of pipelines leading from the platform.
Stolt Offshore was managing the company's 210-ft. saturation diving support vessel, American Constitution, at the platform site when Hurricane Lili approached the Gulf packing more than 120 mph winds.
As the hurricane moved into the Gulf, Total E&P USA. Inc. as well as Stolt Offshore evacuated all personnel. By the time Lili reached the vicinity of Eugene Island 275A in late September, it had grown into a Category 4 hurricane, carrying 140 mph winds.
By October 4. 2002, when Total E&P USA. Inc. returned to the area after the storm had passed, the platform had vanished. No pollution occurred, thanks to the decommissioning and abandonment already performed. The platform jacket had buckled 125 ft. below sea level and had toppled to the west. The deck had broken free of the jacket and rested upright on bottom. Total E&P USA, Inc. asked LoneStar Deepwater, Stolt Offshore, and Noble Denton Consultants, Inc. to provide a feasibility study.
For environmental as well as safety reasons, Total E&P USA, Inc. requested Stolt Offshore not to use Explosives, as many types of marine life, such as sea turtles, and various kinds of fish, populate that area of the Gulf.
After reviewing the options, TOTAL E&P USA, INC. elected to apply for a Special Artificial Reef Site (SARS) to leave part of the platform on location and then follow a multi-staged solution which included removing enough of the jacket structure to ensure a minimum clearance of 85 ft. from the surface of the water for safe navigation purposes; removing equipment still possibly containing fuel or other hydrocarbons; flooding the remaining empty vessels on the deck to make them stable and to prevent them from making an uncontrolled ascent to the surface; and completing the plugging and abandonment operations of the remaining four wells.
The final step, just completed, was for Stolt Offshore to conduct a survey to ensure all procedures were correctly implemented and all regulatory requirements satisfied.