ndependence Hub
Five independent exploration and production companies and
one energy company have come together to develop multiple ultra-deepwater
natural gas discoveries located in the Eastern and Central
Planning Areas of the Gulf of Mexico. The
Independence Hub will be located on unleased Mississippi Canyon Block 920
in a water depth of 7,920 ft (2,414 m). Block 920 is 110 miles from the
Mississippi River Delta and was selected for the permanently anchored host
facility on the basis of favorable seafloor conditions and proximity to nine
anchor gas fields. Hub operator Anadarko expects to begin
installation in April
2006. First gas production is expected July 2007.
The
Independence Hub would produce gas from recent
discoveries that have been made in the Eastern and Central Planning Areas by
lead operator Anadarko Petroleum Company and partners that include Dominion,
Kerr-McGee, Spinnaker, Devon, and Enterprise Partners L.P. The discoveries in
the Eastern Planning Area include Spiderman (DeSoto Canyon Blocks 620 and 621),
San Jacinto (DeSoto Canyon Block 618), Atlas Northwest (Lloyd Ridge Block 5),
Atlas (DeSoto Canyon Block 50), Mondo Northwest (Lloyd Ridge Blocks 1 and 2),
and Cheyenne (Lloyd Ridge Block 399). Discoveries in the Central Planning Area
include Jubilee (Atwater Valley Blocks 305 and 349), Vortex (Atwater Valley
Block 261), and Merganser (Atwater Valley 37). The Hub topsides would be
located in Mississippi Canyon Block 920, 110 miles (177 km) southeast of the
Mississippi River Delta. A steel catenary riser would connect the Hub topsides
to approximately 176 miles (283 km) of 8- to 10-inch-diameter (20-25 cm) flow lines
leading from each wellhead to the Hub.
The Hub itself would be
anchored to the sea bottom by 12 chain and polyester
mooring lines, and would be crewed by 40 people.
The peak daily production levels for
Independence Hub are 850 million cubic feet of gas and 4,250 bbl of
condensate. The Hub platform is designed for an operating life
of 20 years and is estimated to cost approximately $385 million. The Hub has
been designed with excess capacity to tie-back as many as 10 additional fields
to accommodate future discoveries in this ultra-deepwater area.
The Independence Hub project calls for the
completion of 21 exploratory wells and installation of production tubing with a
dynamically positioned completion rig for most of the anchor fields, and a
moored semisubmersible drilling unit for the San Jacinto field. Subsequent
stages involve the placement on the sea bottom of flow lines and manifolds that
control production from each well. This hardware includes a horizontal subsea
production tree on each well, umbilical termination assemblies, pipeline end
terminations (commonly called manifolds), umbilical lines, flow line termination
sleds, and connecting jumpers.
An export pipeline from the Hub,
called Independence Trail, would carry gas and condensate through a
24-inch-diameter (61 cm) pipeline approximately 135 miles (217 km) to a fixed
junction platform located in West Delta Block 68 in 110 ft (34 m) of water. Gas
and condensate would be brought to shore from the junction platform by tie-in to
the Tennessee Gas pipeline for processing at Port Sulphur,
Louisiana. Well completion and Hub installation
are expected to begin
April 2006 with first gas expected August 2007.
The support base at Port Fourchon, Louisiana, will serve as
the port of debarkation for heavy equipment, supplies, and crews for all Hub
construction operations and subsequent production activity. Port Fourchon lies
approximately 150 miles (241 km) northeast of Mississippi Canyon Block 920.
Heliport facilities at Galliano, Louisiana, would be used for crew transport and
light supplies.
Click
here to view the site-specific environmental assessment for the Independence Hub
project.