Appomattox Oil and Gas Project, Gulf of Mexico

Appomattox oil and gas project involves the development of Appomattox and Vicksburg deep-water fields, which are located in 7,200ft-deep waters in the Gulf of Mexico, approximately 130km offshore Louisiana, US.

The deep-water project is being jointly developed by its operator Shell (79%) and Nexen Petroleum Offshore USA (21%), which is a subsidiary of China National Offshore Oil Corp (CNOOC).

The Appomattox field was discovered in 2010, whereas the Vicksburg field was discovered in 2013. Located in the Mississippi Canyon and Desoto Canyon areas of the US Gulf of Mexico,   the deep-water fields are together estimated to hold recoverable reserves of 650 million barrels of oil-equivalent (Mboe).

The final investment decision (FID) on the offshore development project was made in July 2015, following which construction was started.

The Appomattox oil and gas project is expected to produce up to 175,000 barrels of oil equivalent a day (boe/d). It is scheduled to come on-stream by the end of 2019.

Infrastructure facilities for the Appomattox deep-water development

The Appomattox deep-water project is being developed with a semi-submersible, four-column production host platform tied back to the Appomattox and Vicksburg fields.

The newly discovered Rydberg and Gettysburg fields can also be tied-back to the Appomattox platform in future.

Constructed in Geoje, South Korea, the hull of the Appomattox deep-water floating production system (FPS) weighs approximately 40,000 tonnes (t).

The design production capacity of the platform is up to 200,000boe/d. Appomattox will be the biggest floating platform to be operated by Shell in the Gulf of Mexico.

The Appomattox FPS was delivered to the project site in August 2018. It will also be one of the first offshore platforms to have a combined-cycle power generation facility.

The subsea system for the deep-water development project comprises six drill centers, 15 producing wells, and five water injection wells.

The crude oil produced from the Appomattox development will be transported through the 24in-diameter Mattox Pipeline to an existing offshore structure in the South Pass area, from where it will be further conveyed onshore through an existing pipeline.

The Mattox Pipeline will be fully-owned and operated by Shell Pipeline Company.

 Contractors involved with the Appomattox FPS

Samsung Heavy Industries (SHI) was awarded a $300m contract to deliver the Appomattox platform’s hull in July 2015.

The Appomattox FPS was fabricated at Kiewit Offshore Services’ Ingleside fabrication facility in Texas.

Broadmoor was the construction contractor for the 40,000ft² living quarter module on the Appomattox platform.

Heerema Marine Contractors (HMC) was contracted for the transportation and installation of the FPS.

Crowley Maritime was subcontracted to provide towing service for the Appomattox FPS using its Ocean Sky and Ocean Sun tugboats.

Delmar provided the mooring design engineering services for the Appomattox floating platform in 2013.

Subsea contractors for the Appomattox oil and gas field

FMC Technologies (now TechnipFMC) received the subsea contract to supply enhanced vertical deepwater trees, subsea manifolds, topside controls, a control system, and a distribution system for the Appomattox deepwater development in September 2015.

Allseas was contracted for the installation of 145km of 24in-diameter oil export pipeline and 88km of 16in-diameter gas export pipeline for the Appomattox oil and gas project, using Solitaire and Audacia vessels.

Oceaneering was contracted to support the design, fabrication, and installation of ancillary flowline hardware for the Appomattox development.

The contract for the deepwater gas gathering operations for the Appomattox development project was awarded to Williams Partners.