Big Foot Oil Field, Gulf of Mexico, United States of America
The Big Foot oilfield is situated on the Walker Ridge block 29, about 362km south of New Orleans in the Gulf of Mexico, US.
The field lies at a water depth of over 1,500m and is considered the eighth biggest deepwater oilfield in the Gulf of Mexico. It is estimated to hold oil and gas reserves of over 100mboe.
Chevron is the operator of the field with a 60% interest. Statoil (27.5%) and Marubeni Oil & Gas (12.5%) hold the remaining stakes.
The field is expected to come onstream by 2014. Because there is no infrastructure available near the field, it will be developed as a standalone project. Estimated cost of the development is $4bn.
Big Foot oil field discovery
Big Foot was discovered by Chevron in 2006 by the Big Foot No. 2 well. The well was drilled by the Cajun Express semi-submersible rig to a depth of 1,524m. It encountered more than 91m of net oil pay.
Drilling and exploration
Three appraisal and exploration wells have been drilled at the field including the discovery well. The wells were drilled with several sidetracks to define the structure of the field reservoir.
In 2007, Chevron completed the drilling of appraisal well Big Foot No 2, sidetrack No 3. The well was drilled by an ENSCO 7500 semi-submersible rig to a depth of 7,447m.
Another appraisal well called Big Foot No 3, Sidetrack No 2, was drilled to a depth of 7,654m in January 2008.
Development of Big Foot
Initial development plans for the field include seven production wells and three injection wells. These wells will be drilled from the floating drilling and production facility.
Floating, drilling and production facility
Chevron plans to develop the Big Foot field using a dry-tree floating, drilling and production facility.
The hull will be an extended tension leg platform (ETLP) moored in 1,615m of water. It will feature various oil and gas processing systems including gas compression, oil and water treatment and export and utility systems.
The facility will have production and drilling capabilities and accommodation facilities for on-board personnel. It will be designed to export oil to a pipeline or a floating storage and offloading vessel.
Big Foot ETLP
The ETLP proposed for the Big Foot field will feature dry trees and top-tensioned risers. It will have full drilling capabilities and workover and sidetrack capability on the topsides. The ETLP will operate in depths of 1,585m and have a production capacity of 75,000 barrels of oil and 25 million cubic feet of natural gas per day. The ETLP hull is expected to be built in South East Asia and integration will take place in the US.
The ETLP will feature push-up type tensioner systems, which will allow it to withstand the harsh conditions of the area. FloaTec, the contractor for the ETLP, conducted model tests of the ETLP which indicated that it would be able to withstand a 1,000-year hurricane.
In October 2009, Enbridge signed a letter of intent with Chevron, Statoil and Marubeni to build and operate the Big Foot oil pipeline from the Big Foot field.
The pipeline will be located about 170 miles south of the Louisiana coast and requires an investment of $250m. It will be 40 miles long and lie in depths of up to 5,900ft.
The pipeline will contain a 20in diameter pipe and will be able to transport about 100,000bpd. The construction is scheduled for completion by the end of 2012.
Big Foot contracts
In July 2008, INTEC Engineering was awarded a contract for carrying out a pre-FEED study for the project. INTEC provided various development options for the field. The company carried out pre-FEED study for all subsea systems including wellheads, trees, umbilicals and subsea control systems.
Chevron granted a FEED contract KBR in November 2009 for the proposed Big Foot production facility. The scope of work under the contract includes the development of the process design of the facility, structural analysis and layout. KBR will also determine the equipment required for the facility, and design the power generation and distribution system.
In January 2011, KBR was awarded another contract for providing the detailed design for the topsides of the Big Foot ETLP. KBR will also provide engineering and procurement services under the contract.
Gibson Applied Technology & Engineering (GATE) was awarded a contract in October 2009 to provide its services during the FEED stage of the production facility.
As part of the contract, GATE will design the chemical injection system and assist in the selection of chemical vendors. It will also provide overall health, safety and environment support and help in selecting ballast and potable water system material.
In December 2009, FloaTEC was awarded a contract to carry out FEED study for the hull, mooring, spars and risers of the production facility.
FloaTEC will provide overall project management services and develop designs for the hull, foundation piles and risers of the facility. It will also assist in estimating the cost of the facility.
ABS is expected to carry out the design review for the ETLP. The company will conduct classification approvals, equipment fabrication and installation surveys. ABS will start its work after the FEED designs are approved by the classification society.
In February 2011, 2H Offshore won a contract to supply riser systems for the field. 2H Offshore will be responsible for the design, manufacture and installation of two high-pressure drilling risers, 15 production / water injection top tensioned risers and oil and gas export steel catenary risers.
A detailed design contract for the Big Foot pipeline was awarded to Foster Wheeler in March 2011. In the same month, Dril-Quip won a contract to provide drilling equipment for the field.
In May 2011, Baker Hughes was contracted to provide electrical submersible pumping systems for the field's production wells. The systems will enhance hydrocarbon recovery.
GE Oil & Gas's Drilling & Production division was awarded a $45m contract in July 2011 to supply marine riser tensioner system for the ETLP.
Chevron contracted Wood Group in July 2011 to undertake commissioning of the ETLP.