Mars-Ursa (MC807) - Shell

Location

The Mars-Ursa fields are located in the Mississippi Canyon area of the Gulf of Mexico. The Mars field is approximately 209.2 kilometers (130 miles) southeast of New Orleans, while the Ursa field is also in the same general area, on blocks including Mississippi Canyon Blocks 808, 809, 810, 852, 853, and 854.

Discovery and Development

• The Mars field was discovered in 1989 on Mississippi Canyon Block 763 at a water depth of about 966 meters (3,000 feet).
• The Ursa field was discovered in 1991 on Mississippi Canyon Block 854 at a water depth of approximately 1,225 meters (4,000 feet).

Project Details

Mars Field

• Operator and Ownership: Shell Deepwater Production operates the field with a 71.5% interest, while BP holds the remaining 28.5%.
• Development: The initial development aimed to recover about 500 million barrels of oil equivalent (Mboe) with an initial project cost of approximately $1 billion. The project involved the fabrication and installation of a tension leg platform (TLP), drilling and completing wells, and laying pipelines.
• TLP: The Mars TLP, installed in 1996, has an open-truss framing design, measuring 245 feet by 245 feet by 45 feet and weighing about 7,200 tons. It includes modules for the wellbay, living quarters, processing, power, and drilling.
• Production: The Mars field produces approximately 21,000 barrels of oil and 25 million cubic feet of natural gas per day. Oil is transported through the Mars Pipeline system, which connects to the Louisiana Offshore Oil Port (LOOP) pipeline.

Ursa Field

• Operator and Ownership: Shell operates the Ursa field with a 45% interest, while BP holds 23%.
• Development: The Ursa development plan involved a $1.45 billion investment. The Ursa TLP, installed in 1999, is located in about 4,000 feet of water and is designed to withstand hurricane-force waves and winds. It includes modules for the wellbay, drilling, electric power, and crew quarters, along with two processing modules.
• Production: The Ursa TLP supports up to 14 producing wells, including 11 from the TLP and three subsea wells. The platform is designed to handle 150,000 barrels of oil per day and 400 million cubic feet of gas per day, along with 50,000 barrels of produced water per day.

Combined Operations

• Both fields are produced by separate TLPs but are often grouped together under the name Mars-Ursa or MC807. They are considered the largest oil field in the Gulf of Mexico.

Reserves and Production

• Reserves: As of 2019, the remaining reserves for the Mars-Ursa project include approximately 473.2 million barrels of oil and 19,470.48 million cubic meters of gas.
• Cumulative Production: By 2019, the cumulative production was around 1.504 billion barrels of oil and 54,418.8 million cubic meters of gas.
• Annual Production: In 2020, the annual production was about 59.07 million barrels of oil and 2,135.27 million cubic meters of gas per year. In 2022, this was slightly adjusted to 59.42 million barrels of oil and 2,053.36 million cubic meters of gas per year.

Infrastructure and Technology

• TLPs: Both the Mars and Ursa fields use TLPs, which are designed to operate in deepwater environments. The Mars TLP has a deck measuring 245 feet by 245 feet by 45 feet, while the Ursa TLP stretches 4,285 feet from the seafloor to the crown block of the drilling rig.
• Pipelines: The fields are connected by subsea pipelines. For example, the Ursa field has 18-inch pipelines for oil and gas that are laid from Mississippi Canyon Block 810 to a shallow water fixed platform on West Delta Block 143.
• Drilling and Production Facilities: The TLPs include complete separation, dehydration, and treatment facilities. The Mars B Olympus platform, added in 2014, features a self-containing drilling rig and 24 well slots, with potential for subsea tie-backs.

Challenges and Events

• Hurricane Impact: Production was temporarily halted due to Hurricane Katrina in 2005, and the Mars TLP underwent a planned replacement of flexjoints on both its oil and natural gas export lines during the same period.
• Macondo Blowout: The production was also affected by the Macondo blowout in 2010, leading to a drilling moratorium and subsequent decline in production.

Future Development

• Mars B Olympus: The addition of the Mars B Olympus platform in 2014 extended the field’s life to at least 2050. This platform includes subsea wells at the West Boreas and South Deimos fields and is designed to produce approximately 100,000 barrels of oil equivalent per day.

The Mars-Ursa project is a significant component of the U.S. domestic petroleum supply, showcasing advanced deepwater drilling and production technologies.