Decommissioning of Belmont Island, an Offshore Oil Platform

摘要

Belmont Island was a man-made oil drilling and production island located approxi-mately 8,100 feet offshore of the City of Seal Beach, California in about 42 feet of water. The island was located on State Oil and Gas Lease PRC 186, which contained approximately 1,225 acres of tide and submerged lands located within the Belmont Offshore Field in Orange County, California. During the 40-year active life of the Is-land, the wells produced approximately 28 million barrels of oil and 24 million cubic feet of natural gas. The State received over $40 million revenue and the operations grossed over $240 million. ExxonMobil terminated oil and gas production in 1994 due to declining production rates. This fixture in the waters off Seal Beach, survived nearly fifty years as the State's first offshore oil production facility, Belmont Island became the first man-made oil production island removed from the ocean waters off the California shoreline. After a nearly five year permitting process, the physical removal required 21 months, and was completed in January 2002 with no reportable accidents and no environmental incidents. All of the Island's components were completely removed except for components buried below the natural seafloor. The Belmont Island project provides a snapshot of the key issues and technical challenges facing decommissioning projects in today's regulatory climate. Such challenges included the handling of hydrocarbon contamination materials in the caisson core, cutting and removal of lead painted concrete and steel surfaces, and the logistical challenges of handling island materials on a gradually smaller work surface. This paper will provide an overview of these challenges and the approaches developed by the project team to address these challenges.