Appomattox (MC392) - Shell

Location

The Appomattox project is located approximately 129 km (80 miles) offshore Louisiana, USA, in the Mississippi Canyon and Desoto Canyon areas of the Gulf of Mexico. Specifically, the Appomattox field is situated in Mississippi Canyon block 392 and straddles blocks 391 and 348, while the Vicksburg field is located in Mississippi Canyon block 393.

Water Depth and Field Characteristics

The project is in waters with a depth of about 2,255 meters (7,400 feet). The fields were discovered at significant depths, with the Appomattox field discovery well drilled to a depth of 7,643 meters (25,077 feet) and encountering approximately 162 meters (530 feet) of oil pay.

Ownership and Partners

The project is a joint venture between Shell, which operates the project with a 79% stake, and CNOOC Petroleum Offshore USA, a wholly-owned subsidiary of China National Offshore Oil Corp (CNOOC), which holds the remaining 21%.

Discovery and Appraisal

The Appomattox field was discovered in March 2010, followed by an appraisal sidetrack well in the same year. Further appraisal wells were drilled in 2012 to confirm the field's potential. The Vicksburg field was discovered in 2013.

Final Investment Decision (FID) and Construction

The final investment decision for the project was made in July 2015, after which construction began. The project involved the fabrication of the platform's hull by Samsung Heavy Industries, which was delivered to the project site in August 2018. The topside and hull integration took place at Kiewit Offshore Services in Ingleside, Texas.

Infrastructure

The project features a semi-submersible, four-column production host platform, which is Shell’s eighth and largest floating platform in the Gulf of Mexico. The platform has a design production capacity ranging between 120,000 and 200,000 barrels of oil equivalent per day (boe/d).

Subsea System

The subsea system includes six drill centers, 15 producing wells, and five water injection wells. Contractors such as FMC Technologies (now TechnipFMC), Allseas, and Oceaneering were involved in the subsea infrastructure development.

Pipelines

Crude oil produced from the project is transported via the 24-inch diameter Mattox Pipeline, which is approximately 145 km (90 miles) long, to an existing offshore structure in the South Pass area. From there, it is further conveyed onshore using the existing Proteus pipeline system. The Mattox Pipeline is fully owned and operated by Shell Pipeline Company and has a capacity of 300,000 barrels per day (Mbpd).

Production

Production from the Appomattox and Vicksburg fields began in May 2019. The project is expected to produce up to 175,000 boe/d at peak production. As of 2022, the annual production rates were reported as 31.79 million barrels of oil and 575.75 million cubic meters of gas per year.

Reserves

The combined Appomattox and Vicksburg fields are estimated to hold recoverable reserves of approximately 650 million barrels of oil-equivalent (Mboe).

Cost Efficiency and Innovations

Shell has implemented several cost-saving measures, including standardizing equipment, reducing drilling costs, and eliminating the need for a platform rig. These efforts have reduced the project's capital expenditures by 40% and the platform's cost by about 20%, making the project more competitive in a low oil price environment.

Environmental and Regulatory Compliance

The project adheres to strict environmental monitoring and mitigation procedures, as outlined in reports such as the 2022 Protected Species Observer Report. This includes monitoring and mitigation for protected species during survey activities, in accordance with standards set by the Bureau of Ocean Energy Management (BOEM) and the National Marine Fisheries Service (NMFS).

Contractors Involved

Several contractors have been involved in the project, including:

• Samsung Heavy Industries: Hull fabrication
• Kiewit Offshore Services: Topsides and hull integration
• Heerema Marine Contractors: Transportation and installation of the FPS
• FMC Technologies (now TechnipFMC): Subsea equipment
• Allseas: Installation of oil and gas export pipelines
• Oceaneering: Ancillary flowline hardware
• Crowley Maritime: Towing services
• Broadmoor: Living quarters module construction
• Delmar Systems: Mooring design engineering
• Williams Partners: Deepwater gas gathering operations.