Crowley Maritime Corp.’s ocean class tugs have successfully delivered oversized, overweight equipment – comprised of topsides, tendons, piles and more – that are now part of Chevron's massive semi-submersible floating production facility located in the U.S. Gulf, approximately 280 miles south of New Orleans, La. Working alongside the tugs were Crowley’s 455 series high-deck-strength barges, which carried much of the equipment as it was towed offshore. Utilizing the Crowley tugs’ dynamic positioning capabilities, the facility, known as Jack/St. Malo, was successfully moored and made storm safe at a depth of 7,000' between the Jack and St. Malo offshore oil and natural gas fields, which are within 25 miles of each other.
The company’s Houston-based Solutions project management team, which manages the tugs and barges, completed the delivery in three stages of work in both nearshore and offshore waters.
During the first stage, the nearshore phase, the topsides were skidded onto the company’s 455 series barge Julie B at the Keiwit facility dock in Ingleside, Texas, in Corpus Christi, where they were later lifted and installed onto the hull of Jack/St. Malo. Once in place and secured, the Ocean Wind and Ocean Wave next provided assistance by pushing the Jack/St. Malo facility, away from Corpus Christi, through the Port of Aransas, Texas, and out to deeper waters. The Ocean Sun followed the flotilla and was equipped to provide assistance if needed.
Relocation to deeper waters marked the beginning of the second phase of work, the offshore stage. Here, the Ocean Wind and Ocean Sun towed the facility to its final location, alongside the Crowley-contracted tugboat Harvey War Horse II. Also during this phase, the Solutions team arranged for the company’s 455 series barge 455 7, towed by Crowley’s tug Warrior, and third-party barge Marmac 400, towed by Crowley’s tug Pilot, to deliver the piles, or long pipe-like structures that serve as anchors for the platform, to the project site. Finally, the Marty J, towed by the Pilot, made three subsequent trips to the installation site to deliver additional equipment – including chains, connectors and line reels – that were used in the mooring of the floating facility.
In the final stage, the positioning phase, the Ocean Wind, Ocean Wave, Ocean Sky, Ocean Sun and Harvey War Horse II worked together to hold the Jack/St. Malo in its final location, and remained on site in a star pattern to provide support as the spar was connected to its moorings and made storm safe in more than 7,000' of water.
Crowley’s ocean class tugs are modern ocean towing twin-screw vessels with controllable pitch propellers (CPP) in nozzles, high-lift rudders and more than 147 MT bollard pull. The first two ocean class vessels, Ocean Wave and Ocean Wind, are classed as Dynamic Positioning 1 (DP1) tugboats and are twin-screw, 146'x46'x25' tugs have a design draft of 21'. The second two tugs of the class, Ocean Sky and Ocean Sun, are classed as DP2 and are 10 feet longer. All four vessels are capable of rig moves, platform and Floating Production, Storage and Offloading (FPSO) unit tows, emergency response, salvage support and firefighting.
Scheduled to begin producing oil and natural gas later this year, the facility will have a capacity of 170,000 bbls. of oil per day and 42.5 million standard cu. ft. per day of natural gas. Jack/St. Malo will act as a hub for the 43 subsea wells, including pumps and other equipment on the seafloor.