J-lay Installations Lessons Learned

Abstract

Abstract The installation of ultra deep-water projects in recent years has been a significant goal achieved by Saipem in the field of laying performance. Hoover-Diana During 2000, the Saipem 7000 installed the ExxonMobil Hoover-Diana steel catenary risers and flowlines in 1464-m water depth by J-lay method in the Gulf of Mexico. Saipem scope, relevant to pipelaying, was the installation of two 10-inch OD flowlines and their steel catenary risers, the 18-inch oil and 18-inch gas-export steel catenary risers and the 6-inch flowline and its steel catenary riser. Blue Stream Completing in 2002, the Saipem 7000 installed twin 24-inch pipelines crossing the Black Sea in a water depth of 2150-m The Blue Stream Project is undoubtedly one of the most challenging projects of its type ever attempted because of the difficulties in terms of design, construction, organization and logistics. Saipem scope included design, procurement, construction and pre-commissioning of two 24-inches OD × 31.8-mm pipelines between Russia and Turkey in the Black Sea. The total length was of about 380-km each. Girassol During November 2001, the SaiBOS FDS, installed twin 16-inch pipelines that link the Girassol FPSO with its loading buoy in a water depth of 1400-m in the Angola waters installation included a 450 meters central section of buoyancy module. SaiBOS FDS scope also included the installation of 22 flexibles, varying between 11 and 14-inches outside diameter, between the riser towers and the FPSO, and of more than 47,000-m of umbilicals. Canyon Express During 2002, SaiBOS FDS installed two 90-km long 12 inches flowlines in a maximum water depth of 2230-m, in the Gulf of Mexico. This pipeline installation is the deepest in the world. The installation also includes twelve inline and termination Sleds with a submerged weight up to 25-ton. These Sleds were installed as an integral part of the flowline pipelay. The present paper outlines the many challenges faced as well as the solutions adopted that contributed to an effective development in pipelaying technology. Saipem 7000 The semi-submersible crane vessel Saipem 7000, equipped with two 7000-ton cranes mounted on its bow, was adapted to accommodate a pipelay system in the form of J-lay tower to meet the challenges of deepwater and ultra-deepwater developments. The J-lay system on board Saipem 7000 is designed for operations up to water depths exceeding 3000m deep (Figure 1). The J-Lay tower can move up to 20 degrees off the vertical. J-Lay system can be easily installed on the vessel, when it is required to work in J-lay mode and then removed to allow Saipem 7000 to act in the heavy lift mode when needed. The modular tower with its pin connections to the vessel is equipped with three tensioners each of 175-ton capacity. There are also 2 × 500-ton friction clamps for enhanced safety. It also houses two workstations - one for welding and the other for non-destructive testing and field joint coating. The system includes an Abandonment & Recovery winch with a capacity of 555-ton. The J-lay system is designed for rigid pipes with diameters from 4-inches to 32-inches in quadruple joints length.