David Paganie, Managing Editor
The world’s deepest platform, subsea completion, steel catenary riser (SCR) installation, and export pipeline. Just a few reasons whyOffshore has selected the Independence Hub project in our Top 5 for 2007. Covering 142 blocks or 1,800 sq mi (4,662 sq km) in the Gulf of Mexico, this massive undertaking represents not only a number of industry firsts, but a true example of multiple companies pulling together to reach a common goal.
Six companies (Enterprise Products Partners, Helix Energy Solutions, Anadarko, Devon, Dominion, and StatoilHydro) collaborated to bring this $2-billion project from discovery in 2001, to proposal in 2003, to first gas on July 20, 2007. The Anadarko-operated Atlas No. 1 well in almost 9,000 ft (2,743 m) water depth in Lloyd Ridge block 50 represented first production flowing at 20 MMcf/d.
Independence Hub, the world’s largest offshore natural gas processing facility installed in a world record water depth, is connected to 10 subsea fields in up to 9,000 ft (2,743 m) water depth.
Independence Hub is anchored by a 12-line taut polyester/chain mooring system connected to 12 suction piles in Mississippi Canyon block 921 in 8,000 ft (2,438 m) of water. This represents the third application of polyester and synthetic moorings in the GoM, according to ABS, facility classification society.
The 1 bcf/d semisubmersible production facility processes production from 10 fields: Atlas (Lloyd Ridge blocks 49/50); Atlas NW (Lloyd Ridge block 5); Jubilee (Atwater Valley blocks 305/349 and Lloyd Ridge blocks 265/309); Merganser (Atwater Valley blocks 36/37); San Jacinto (DeSoto Canyon blocks 618/619); Spiderman (DeSoto Canyon blocks 620/621); Vortex (Atwater Valley blocks 217/261 and Lloyd Ridge blocks 177/221); Mondo NW (Lloyd Ridge blocks 1/2); Q (Mississippi Canyon blocks 960/961/1004/1005); and Cheyenne (Lloyd Ridge block 399).
All fields are developed with subsea infrastructure and connected to the central processing facility via 1,100 mi (1,770 km) of umbilicals and 210 mi (338 km) of flowlines. Anadarko contracted FMC Technologies to supply 17, 10,000-psi rated Enhanced Horizontal Christmas Trees (EHXT), manifolds, valves, and MAX 8 connector hubs for inline sleds, PLETs (pipe line end terminations), and jumpers.
The valves on the subsea trees are controlled through touch-sensitive data screens installed on the deck and in the control room of the central processing platform.
With the anchor fields situated up to 45 mi (72 km) from the processing hub in up to 9,000 ft (2,743 m) water depth, installation of the world’s largest monoethylene glycol (MEG) reclamation unit was required with a feed capacity of 7,800 b/d of MEG/produced water to keep the produced gas from forming hydrates or freezing.
Gas flows from the subsea fields to four-column semiIndependence Hub fitted with capacity to process 1 bcf/d of gas, 5,000 b/d of condensate, and 3,000 b/d of water. The product then moves through Enterprise Products Partners-owned Independence Trail, comprising 134 mi (216 km) of 24-in. (61-cm) pipe, to West Delta block 68. From there, the gas flows to shore.
Once the project reaches full processing capacity, it will represent 10% of all natural gas production in the Gulf of Mexico and comprise 1.5% of overall US gas supply.Hub throughput will produce enough energy to heat or cool 11,000 US homes for one year, according to Anadarko.
Independence Hub is owned by Independence Hub Llc (80% Enterprise Field Services Llc; 20% Helix Energy Solutions). Participating operators include Anadarko (Hub operator), Devon, Dominion, and StatoilHydro.
World records
- World’s deepest platform in 8,000 ft (2,438 m) water depth
- World’s largest offshore natural gas processing facility (1 bcf/d)
- World’s deepest subsea production tree in 9,000 ft (2,743 m) water depth on Cheyenne field
- World’s deepest flowline installation
- World’s deepest steel catenary riser (SCR) installation
- World’s deepest export pipeline and SCR, originating in 8,000 ft (2,438 m) water depth, using the S-lay method and a maximum installation tension of 550 tons (499 metric tons)
- World’s largest single subsea umbilical order
- World’s longest mooring lines at 2.4 mi (3.9 km)
- World’s largest monoethylene glycol (MEG) reclamation unit with a feed capacity of 7,800 b/d of MEG/produced water
- First use of carbon fiber rod in subsea umbilicals
- Deepest suction pile installation
- Heaviest SCR load on a deepwater floating facility at 650 tons (590 metric tons).
Major contractors
Atlantia Offshore – Hull and mooring systems design, fabrication, construction and dry transportation to the staging site at Ingleside, Texas
Alliance Engineering – Topsides engineering
Kiewit Offshore Services – Topsides fabrication and installation onto the hull
Heerema Marine Contractors – Hull and mooring systems transportation and installation
Allseas USA – Installation of the flowlines and gas export pipeline
FMC Technologies – Supply of subsea trees, manifolds, valves, and connector hubs for inline sleds, PLETs, and jumpers
ABS – Classification society
