The pipe-in-pipe system will protect against the formation of wax, asphaltenes, and hydrates, each of which can form within the production flow if temperature within the pipe falls below critical operating conditions. Pipe-in-pipe systems designed to facilitate production flow in cold, deep waters consist of an inner carrier pipe, a layer of insulation, and an outside “jacket” pipe.
The ENI K2 field includes two subsea centres on Green Canyon Block 562 in water depths ranging from 1280- 1410m of water; a two- to three-well cluster in the North Fault Block (NFB) area; and a one- to two-well cluster in the South Fault Block (SFB) area. The K2 subsea system will develop wells that will tie back around 12km to a tension leg platform host facility standing in 1410m water. Production start-up is planned for March, 2005, with a subsea system design capacity of 60,000brl/d of oil.
The K2 field development scheme calls for a dual, piggable, 7-in diameter carrier flowline. The jacket portion of the pipeline is 12in diameter, with up to 2.5in of insulation planned between the carrier and jacket pipes. The pipelines will connect to the host platform via two steel catenary risers (SCRs), each 7in diameter and approximately 2300m in length. The SCRs will include wet, buoyant, insulation to minimize the impact of top tension loads on the host facility.