Delmar, Shell Reach Record Mooring Depths

2-D image of a mooring operation

Delmar Systems, Inc. and Shell Exploration & Production Company established a world-record depth for moored vessels using the latest in mooring technology.

The Transocean Sedco Forex 5th generation semi Deepwater Nautilus was moored in 8,009 feet of water in the Gulf of Mexico with the deepest anchor at 9,100 feet. This ultra deepwater mooring project was accomplished using high strength synthetic mooring rope connected to suction anchors.

The current mooring system consists of eight, 9′ 5″ diameter by 70′ long suction anchors embedded in the seafloor and attached to 9,000 feet of 6 ¼” polyester mooring rope and 3,500 feet of 3 ¾” steel wire rope. The polyester and steel rope is connected to the anchor, via the patented Delmar Subsea Connector. The lighter weight mooring rope is an alternative to traditional steel wire rope. The trade-off in reduced weight increases the rig’s variable deck load, permitting the rig to anchor in deeper waters.

The world-record installation was accomplished in a two-step process, whereby the suction anchors were pre-installed using only one anchor-handling vessel, the Gary Chouest, owned by Edison Chouest Offshore, Inc. The eight mooring legs were then pre-installed at a later date, allowing for quick connection once the rig arrived on location.

Delmar has reached a milestone in establishing this new world record mooring depth. The ability to moor conventional semi’s in these waters and beyond has been non-existent until this technology was developed and fully tested. As the oil industry continues exploring for hydrocarbons in the most challenging water depths and environments, this method and new lighter weight technology will play a major role in achieving the industry’s deepwater goals.