Brutus (GC158) - LLOG Offshore

Location

The Brutus field is situated approximately 165 miles southwest of New Orleans, USA, in the northern Green Canyon area of the Central Gulf of Mexico.

Discovery and Development

The discovery well for Brutus was drilled in December 1988, and an appraisal well was drilled in 1994 on the same block. Development plans were announced by Shell in April 1999.

Platform and Infrastructure

The field is developed using a conventional, dry-tree tension leg platform (TLP). The TLP was installed in mid-2001 at a water depth of 2,985 feet. The platform consists of:

• A hull with four circular steel columns, each 66.5 feet in diameter and 166 feet high, linked by a rectangular section using pontoons. The hull weighs around 13,500 tons with an aggregate displacement of 54,700 tons.
• The deck is approximately 245 feet square and 40 feet high, comprising five modules: processing, drilling, power, living quarters, and a wellbay. The total topside weight is about 22,000 tons, including all process equipment and the drilling rig.

Production

• First production began in early August 2001.
• The TLP is designed to accommodate a peak gross production of approximately 110,000 barrels of oil per day (bpd) and 150 million cubic feet (Mcf) of gas per day.
• Initially, the field produced 60,000 bpd and 90 million cubic feet of natural gas per day from four wells. Following a shutdown in February 2002 due to valve failures, production capacity was increased to 130,000 bpd.

Reserves and Production Profile

• The estimated ultimate gross recovery from the Brutus development is greater than 200 million barrels of oil equivalent (boe), with a 70:30 oil to gas ratio.
• The oil has an average API gravity of low-mid 30 degrees and a sulfur content of 1.5%.

Transportation

• Oil is piped approximately 26 miles via a 20-inch diameter pipeline to the South Timbalier 301 B platform, where it is connected to the existing Amberjack System.
• Gas is piped 24 miles via a 20-inch gas pipeline and connected to the existing Manta Ray Offshore Gathering system in Ship Shoal Block 332.

Subsea System

• The Glider subsea system, comprising two wells, was tied back to the Brutus TLP in July 2004 via a 6-inch buried and insulated flowline. This was the first subsea tieback to a TLP.

Operational Role

• The Brutus facility serves as a hub for neighboring satellite fields in the northern Green Canyon area, including EnVen's Glider (GC 248) and LLOG's J. Bellis (GC 157).

Challenges and Maintenance

• Initially, Brutus performed below expectations due to problems, but these were addressed during a shutdown in February 2002, which also allowed for an increase in production capacity.

In summary, the Brutus field is a significant offshore oil and gas project utilizing advanced TLP technology, serving both as a production facility and a hub for surrounding fields in the Gulf of Mexico.