June 2013, Vol. 240, No. 6

Projects

Rig Salvage In Gulf

In mid-December, a retired jack-up drilling rig under tow from Fourchon, LA to be dismantled in Texas began taking on water. Despite being in an area of heavy marine activity in the Gulf of Mexico, the tow captain maneuvered the sinking rig into a little-used section of the Vermillion leasing block where the seas finally washed over the main deck and forced the rig to the ocean floor.

Foul weather prevented immediate salvage response and the rig was left to the assault of high winds and rough seas. A debris field could be seen coming from the wreck site, making it obvious the rig would break apart. The U.S. Coast Guard deemed the wreck a hazard to navigation and, although there was no fuel or environmental threat on board, demanded immediate action.

Inland Salvage Incorporated (ISI), Harvey, LA was awarded the salvage contract and began organizing the effort. After working together on Hurricane Sandy response in the Northeast, ISI teamed with Titan Salvage of Pompano Beach, FL. Titan’s naval architects began performing stability calculations while ISI and Titan personnel mobilized to the wreck site.

Divers began underwater surveys to inspect the damage to the structure and condition of the jacking system. Salvage Master Gordon Olson determined it would be best to approach the salvage from two fronts. One dive team would work to restore buoyancy to the barge and mud mat while a second would attempt to re-establish control of the now-submerged jacking system.

Salvage Engineers developed an external hydraulic supply and control unit that was connected to the existing jacking system by divers working in the confined spaces of the rig. Divers penetrated into the barge tanks to install salvage pumps and restore the rig’s dewatering system for the mud mat. There were several delays in progress as weather fronts moved across the Gulf, but crews were able to remain on site, safely jacked up above the sea conditions in the lift boat.

With the work complete and a break in the weather, the process of raising the barge using the rig’s own jacking system began. The hydraulic repairs were successful and the barge slowly moved up the rig’s legs. As the main deck broke the water’s surface, salvors began pumping the barge to lessen the load on the hydraulic jacks. This continued until the barge was completely jacked up out of the water. Crews then evaluated the condition of the barge to develop a plan that would make it seaworthy again.

With severe structural corrosion of the vessel requiring significant repair work and a short window of good weather, it was decided to set the jack up onto a receiver barge that could deliver the rig to the scrap yard. The rig was jacked high enough above the water to allow an ocean going receiver barge to be floated underneath,

Once the floating vessel was in position, the jacks began lowering the rig onto the receiver deck. The rig’s mud mat was then raised up under the receiver barge and the tow was underway. The barge and rig combination safely arrived at its destination where the process was reversed and the jack-up rig delivered.

Inland Salvage worked closely with the U.S. Coast Guard during all phases of the operation.