Vicksburg A (MC393) - Shell

Vicksburg A (MC 393) Field Profile

Location and Geology

The Vicksburg A field is located in the ultra-deepwater region of the Gulf of Mexico, specifically at the border of the Mississippi Canyon and DeSoto Canyon protraction areas. It is situated in Mississippi Canyon block 393 and also extends into De Soto Canyon block 353, at a water depth of approximately 7,401 feet (2,269 meters).

The field is part of the Norphlet geological formation, which is characterized by high pressures and temperatures, as well as the presence of corrosive gas. This formation extends from onshore to the deep waters of the Gulf of Mexico.

Discovery and Sanction

The Vicksburg A field was discovered in July 2013 by a discovery well drilled to a total depth of 26,385 feet (8,042 meters) at a water depth of 7,446 feet (2,269 meters). The discovery well encountered more than 500 feet (152 meters) of net oil pay.

The project was sanctioned on July 1, 2015, as part of the broader Appomattox development project.

Ownership and Partners

The Vicksburg A field is a joint venture between Shell, which operates the field with a 79% stake, and CNOOC Petroleum Offshore USA, a wholly-owned subsidiary of CNOOC, which holds the remaining 21%.

Reserves and Resources

The Vicksburg A field, together with the Appomattox field, is estimated to hold recoverable reserves amounting to approximately 650 million barrels of oil equivalent (MMboe).

Production

Production from the Vicksburg field began in May 2019 as part of the Appomattox Deepwater Development project. Peak production from the combined Appomattox and Vicksburg fields is estimated at approximately 175,000 barrels of oil equivalent per day (boe/d).

As of 2021, the Vicksburg field had recovered 69.67% of its total recoverable reserves, with production expected to continue until the field reaches its economic limit in 2025.

Infrastructure and Development

The development of the Vicksburg A field involves a semisubmersible, four-column production host platform, which is Shell’s eighth and largest floating platform in the Gulf of Mexico. The platform supports a subsea system featuring six drill centers, 15 production wells, and five water injection wells. The infrastructure has a design capacity ranging between 120,000 boe/d and 200,000 boe/d.

Crude oil produced from the project is conveyed via the Mattox Pipeline, a 24-inch diameter pipeline that is approximately 90 miles (145 kilometers) long, to an existing offshore structure in the South Pass area and further supplied onshore using the existing Proteus pipeline system. The Mattox Pipeline has a capacity of 300 thousand barrels per day (Mbpd) and features pre-installed subsea connection points for future interconnections.

Cost Efficiency and Contractors

Shell has been able to reduce the project costs significantly by increasing the efficiency of the project’s design and scope, and by lowering drilling costs. The company reduced the platform’s cost by approximately 20% based on experience gained from previous projects in the Gulf of Mexico.

Contractors involved in the project include Delmar for mooring design engineering services, and TechnipFMC for the high-pressure/high-temperature (HP/HT) full-field subsea solution.

Future Prospects

The Appomattox infrastructure is being considered for potential connections to other nearby prospects, such as the Gettysburg and Rydberg fields, which could further increase the total estimated discovered resources in the area to more than 800 MMboe.