A 20-IN. PIPELINE HAS BEEN re-routed through a platform on Gulf of Mexico Main Pass Block 69 for Shell Oil Co. affiliate Equilon Enterprises LLC., Houston.
Global Divers & Contractors Inc., a subsidiary of Global Industries, Houston, performed the work in what it called the largest series of mechanical pipeline connectors ever used in one project application. The project was completed in August to increase flow volumes in the 20-in. line.
The series of three pipeline connectors (a 20 x 12-in. hot tap, a 20-in. line stopple, and a 20-in. end connector) re-routed one end of the 20-in. pipeline to a pump-station platform (Fig. 1). The platform, in 33-ft water, had been installed in July 140 ft from the 20-in. line.
To reroute the pipeline from the platform required installing in reverse order a duplicate series of 20-in. connectors. Two 20-in. tie-in spools, each 140-ft long, connected the platform risers to the 20-in. line at each end connector.
To maintain production flow during the operation, Global Divers installed a 12-in. pipeline by-pass spool that connected the hot taps and diverted production during the re-route operation.
Also installed were four sets of anchor-pile support assemblies along the 20-in. line to provide extra support against the soft bottom soil. Each anchor assembly was hydraulically drilled 65 ft into the sea bottom and secured by clamps to the pipeline.