ABS to class Independence Hub semi
ABS will class the Mississippi Canyon 920 Independence Hub, a semisubmersible facility destined for 8,000 feet of water in the Gulf of Mexico.
The platform is to be owned by Independence Hub, LLC, an affiliate of Enterprise Products Partners, L.P., and operated by Anadarko Petroleum. It is is planned for Mississippi Canyon Block 920 and will serve as a gas-gathering hub for nearby fields.
Platform construction begins first quarter 2005.
Atlantia Offshore of Houston is the hull contractor, providing hull design, the mooring system and the SCR riser system design.
Jurong Shipyard in Singapore will fabricate the hull. Alliance Engineering, also of Houston, is designing the process facilities. Kiewit Offshore Services of Ingleside, Texas, will fabricate the deck and provide process equipment assembly and on-shore hook-up.
Atlantia will transport the hull from Singapore to Ingleside, where Kiewit will integrate the hull and topsides. Heerema will install the integrated structure as well as the moorings and pilings.
Installation is slated for fall 2006, with peak gas production estimated at 850 million cubic feet per day.
Describing the project as "massive," Bob Major, ABS project manager, advises that ABS' selection for the contract lies in its extensive experience in the Gulf of Mexico, its ability to act on behalf of the U.S. Coast Guard and its expertise with polyester moorings.
The Mississippi Canyon 920 Independence Hub will represent the third application of polyester/synthetic moorings in the Gulf of Mexico.
"We have the deepwater experience and global interface necessary to support a project of this nature. Importantly, we work closely with our clients for offshore survivability while also working to avoid any costly delays to the schedule," said Major.
Jim Guion, Enterprise's project manager, says that Enterprise has worked successfully with ABS on the Prince and Marco Polo Gulf of Mexico deepwater projects.
ABS domestic experience in the deepwater Gulf of Mexico wqas another factor in its selection for classification.
"ABS has the ability to impact timely approvals of offshore facilities because of its established agreement to act on behalf of the U.S. Coast Guard," said Guion.
Major adds that ABS understands the various "nuances" involved in understanding U.S. Coast Guard codes. "For instance, while the code specifies 'no less than 22-gauge wire' for equipment onboard an offshore facility, in specific instances, the U.S. Coast Guard has accepted smaller-gauge wiring for certain equipment, such as computers, which draw less energy," said Major.
PLATFORM SAFETY, READINESS
The new platform will be classed an Maltese Cross A1 Floating Offshore Installation (FOI).
Areas of emphasis include platform stability, structural integrity and buoyancy after damage while also considering the unit's compliance and readiness in terms of fire-fighting capability and life-saving equipment. "Our goal is to provide safe working conditions for people at sea while also protecting the environment," said Major. He describes the sheer magnitude of the two-deck platform as "stunning." The platform's footprint is 232 feet wide and 232 feet long and provides 8,600 tons of cargo capacity on deck for process equipment, motor control center buildings, three-level living quarters and other necessary facilities.
SYNTHETIC MOORING LINES
The facility includes five Solar Mars gas compressors, three Taurus generators and a vertical flare tower. The platform has an operating draft of 105 feet; displacement of 50,000 tons; and will include 12 polyester mooring lines, connecting to the unit's 12 suction pilings.
"Synthetic mooring lines are lighter weight than steel moorings, offering the deepwater market neutral buoyancy and a much lighter load on the overall platform system. As result, operators can dedicate more space to payload, such as production equipment, and less to supporting the weight of heavy chains," said Major.
He adds that ABS issued the industry's first Guidance Notes on Synthetic Moorings in March 1999. Initially, six fields are targeted for tie-in to Independence Hub. All the wells will be subsea completions and are located up to 30 miles from the hub platform:
Atlas and Atlas Northwest on Lloyd Ridge Blocks 5/49/50 and operated by Anadarko
Jubilee on Atwater Valley Blocks 305/349 and operated by Anadarko
Merganser on Atwater Valley Blocks 36/37 and operated by Kerr-McGee
Spiderman on DeSoto Canyon Blocks 620/621 and operated by Anadarko
San Jacinto on DeSoto Canyon Blocks 618/619 and operated by Dominion
Vortex on Atwater Valley Blocks 217/261 and operated by Kerr-McGee
Preliminary activities are already under way for the project, with ABS participating in initial meetings to clarify ABS requirements for fire protection, hull structure and piping issues as early in the process as possible, says Major.
"The designers are anxious to get this information to maintain their schedule and to avoid any rework. We've made ourselves available, and we're making initial comments that will help move the process along," he said.
Major says that ABS is assisting the designers in applying the requirements of the "ABS Guide for Building and Classing Facilities on Offshore Installations" for structural fire protection. The Guide requires that the decks and bulkheads are designed to withstand a hydrocarbon fire in certain circumstances. Relevant issues include requirements for shielding critical equipment, evacuation plans, fire walls, life boats and stairways.
As part of this process, ABS will apply the joint U.K. Department of Energy, Norwegian Petroleum Directorate standards "Hydrocarbon Fire Resistance Test for Elements of Construction for Offshore Installations" in its review of the platform.
ABS will look at structural fire protection ratings for buildings, including accommodations/quarters and the motor control centers. For instance, an "H-60" rating provides a bulkhead or deck with at least 60 minutes to spare before failure; i.e. passage of flame or smoke, in the case of a hydrocarbon (gas or oil) fire. An "A-60" rating provides a bulkhead or deck with at least 60 minutes before failure for a fire emanating from combustible materials; i.e., mattresses, wood, supplies, furniture, etc. ABS also expects platform designers to provide some method of isolating damaged process piping from marine or safety-critical piping, with the likely approach calling for a valve with an adequate pressure rating. The process piping can then be designed to a safety standard that may result in lower costs
ABS holds a 47 percent market share for classing floating offshore installations, including semisubmersibles, tension leg platforms, spars and floating production, storage and offloading units.
"We've served as the certified verification agency (CVA) for all types of FOI units, designed and fabricated both domestically and overseas. We're eager to serve as CVA for this frontier project that will take the industry into a new realm of deepwater," said Major.
MORE NEWS STORIES