Light-weight, fast-track hubs for the Gulf of Mexico

May 6, 2003
The Marco Polo main deck will be floated later this month from the Kiewit Yard in Texas. The production deck for this Green Canyon block 608 TLP was floated in mid April, said Mike Mahoney, vice president of Alliance Engineering's deepwater unit during a breakfast event at Offshore Technology Conference in Houston.

The Marco Polo main deck will be floated later this month from the Kiewit Yard in Texas. The production deck for this Green Canyon block 608 TLP was floated in mid April, said Mike Mahoney, vice president of Alliance Engineering's deepwater unit during a breakfast event at Offshore Technology Conference in Houston.

Designed by Alliance, the Marco Polo TLP, to be installed later this year, met with some late and wide-ranging changes, Mahoney said. The Anadarko find was initially to be produced from a six-dry-tree well. The TLP was not thought to need full drilling capabilities, and it was to produce 35,000 b/d. After El Paso and Anadarko firmed up a new production plan, however, the design was not sufficient to handle the planned output, Mahoney said. He said the first upgrade, to 100,000 b/d and 250 MMcf/d capacity, and the second, to 120,000 b/d and 400 MMcf/d capacity, posed some challenges.

"A lot of equipment had already been bought," he said. "Fabrication was already under way."

The hull is being constructed at Samsung's yard in Korea. The structure is complete, Mahoney said, and outfitting is in progress.

The Marco Polo project follows on the heels of the Horn Mountain Spar Alliance designed to meet light-weight, fast-track specifications.

On Mississippi Canyon block 127 in 5,420 ft of water, the BP-operated Horn Mountain truss Spar has 14 dry tree slots, making it the deepest dry tree development. The Spar needed to be capable of performing sidetrack drilling from its large well bay, Mahoney said. In its origianal development vision, then operator Vastar pushed the project into a fast-track lineup, bumping the onstream date from 2Q 2004 to late 2002, he said. The ability to drive down costs of topsides and the hull prompted the accelerated production schedule, he said.

The hull was installed in May and June 2002.

Mahoney said the project met its ambitious schedule becuase of early decision making and good project managment. Additional factors, he said, were a reduced topsides schedule by overlapping fabrication and engineering, and using a lighter and smaller topsides and hull.

"The hull and topsides ended up in almost a dead heat on the critical path," Mahoney said.

At its November 2002 start-up, the Horn Mountain development became the deepest free-floating Spar production system. Going onstream months ahead of schedule, the project went from discovery in August 1999 to sanction in October 2000 to first oil in just under 40 months. The facility is designed to process 65,000 b/d and 70 MMcf/d. Oxy is a partner in the field.

Alliance works mostly with projects that require light-weight facilities, often on a fast-track approach.

"How far can we carry this?" he asked. "We'd like to carry this as far as we can."

Alliance has recently also worked with the Magnolia TLP, designed for Garden Banks block 783 for ConocoPhillips and Ocean Energy, and the West Seno B TLP, desgined for for Unocal to be installed off Indonesia.

05/06/03