Helix successfully completed installation of two 86-ton pipeline-end-termination (PLET) modules as a prelude to the initiation of production of Murphy Oil Co.’s Thunder Hawk development in the deepwater Gulf of Mexico.
The project marked the first time Helix had installed PLETs of this dimension in 6,000-plus water depth using a single-line crane. The units were installed from the 380-ft Helix Intrepid reeled pipelay vessel, which has 400-ton crane capacity and a 10,000-ft water depth capability.
A total of four PLETs were installed, including two 8-in infill flowline units and two 12-in. modules for tie-back into the Mardi Gras export lines. The individual mud-matted PLETs measured 40-ft x 40-ft with 20-in. connectors for the gas export line and 16-in. connectors to the oil line. With the connected 12-in. pipeline, the PLETs weighted up to 200 tons each. Helix is in the preparation phase of installing 16-in. and 20-in. export jumpers associated with the PLETs.
Spitzer Industries fabricated the PLETs at its Green Bayou facility near Houston.
“While we previously have stabbed and laid down PLETs with only a crane, we never before had done so with ones this large and in this water depth. This job also required that the 8-in, PLETs be installed by sidestepping beneath a DP drilling vessel. Our project team developed the installation protocol for the PLETs, and the Intrepid crew carried out the plan with precision,” said Helix Energy Solutions Project Manager Ron Tomon.