Big Foot is an ultra-deepwater oil and gas field located in the Gulf of Mexico, approximately 360km off the coast of New Orleans, US. The Chevron-operated offshore field produced its first oil in November 2018.
Chevron has a 60% working interest in the Big Foot project, while the other development partners include Equinor (27.5%) and Marubeni Oil and Gas (12.5%).
The offshore project, originally estimated to cost $4bn, was sanctioned by the development partners in December 2010 and construction works started in 2011.
The field was expected to be brought on stream by 2015. It was, however, delayed due to the technical failure in tethering the giant production platform to the seabed with the sinking of nine out of the total 16 tendons in June 2015.
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The total investment in the project is believed to have exceeded $5.1bn.
The Big Foot field is expected to produce up to 75,000 barrels of crude oil and 25 million cubic feet (Mcf) of natural gas a day over its estimated project life of 35 years.
Big Foot discovery and appraisal details
Located at a water depth of 1,584m in the Walker Ridge Block 29 in the deepwater of Gulf of Mexico, the Big Foot oil and gas field was discovered by the Big Foot-2 discovery well using the Cajun Express semi-submersible rig in 2006.
Drilled to a depth of 1,524m, the discovery well encountered net oil pay of 91m.
Further apprised by three appraisal wells in 2008, the Big Foot field is estimated to hold more than 200 million barrels of recoverable oil-equivalent resources.
Big Foot field development details
The Big Foot offshore field uses a 15-slot drilling and production extended tension-leg platform (ETLP). Placed at a water depth of 1,615m, the Big Foot production platform is considered to be the world’s deepest platform of its kind.
The integrated drilling and production platform features dry trees and top-tensioned risers.
The topside of the platform has a dry weight of 28,000t and houses oil treatment and gas compression systems along with inlet oil and gas separation, water treatment and injection facilities, and living quarters.
The Big Foot ELTP is capable of producing 75,000 barrels of crude oil and 25Mcf of natural gas a day.
The hull of the ELTP was fabricated in Singapore, whereas the topsides were fabricated in Aransas Pass, Texas, US.
The topsides integration and onshore commissioning of the ELTP was carried out at Kiewit’s yard in Ingleside, Texas.
Oil supply from the Big Foot field
The oil produced from the offshore field is transported through Enbridge’s 64km-long and 20in-diameter Big Foot oil pipeline that connects the onshore gathering system in Louisiana.
The pipeline, built with an estimated investment of $200m, has the capacity to transport up to 100,000 barrels of crude oil a day from the offshore production facility.
The Big Foot oil pipeline was undertaken by Enbridge as part of the Walker Ridge Gas Gathering System project.
Contractors involved
The pre-front-end engineering and design (FEED) contract for the subsea systems of the Big Foot project was awarded to INTEC Engineering in July 2008.
KBR was awarded the FEED contract for the Big Foot production facility in November 2009.
Floatec, a joint venture between Keppel FELS and J Ray McDermott, was awarded the FEED contract for the mooring, risers, and hull of the Big Foot production facility in December 2009.
KBR was contracted for the detailed engineering, procurement management, and construction support for the topsides of the Big Foot facility in January 2011.
Gibson Applied Technology and Engineering (GATE) provided the detailed design for the chemical injection system installed at the offshore production facility.
2H Offshore, an Acteon group company, was contracted for the detailed design and delivery management of riser systems for the Big Foot drilling and production platform in February 2011.
Drill-Quip provided the drilling equipment for the Big Foot development project, under a contract awarded in March 2011.
Foster Wheeler was contracted for the detailed design of the Big Foot oil pipeline in March 2011.
Wood Group was awarded the Big Foot ELTP commissioning contract in July 2011, while Mietec was contracted for the electrical and instrumentation hook-up and commissioning services for the ETLP.
Baker Hughes, a subsidiary of General Electric (GE), supplied the electrical submersible pumping (ESP) systems for the Big Foot production wells.
Nabros provided the deepwater drilling rigs for the Big Foot ETLP, while Promat Marine provided acoustic and fire-rated linings solutions for the platform.
The Big Foot ELTP was assembled and tested at Kiewit Offshore Services' yard in Ingleside, Texas, US.