Deimos Offshore Field, Mexico and US, Mexico

The Deimos offshore field is 3,000ft deep in the Mississippi Canyon Blocks 762 and 806, located adjacent to the Mars production unit in the Gulf of Mexico.

Shell Exploration and Production Company (SEPCO) is operating the field with a 71.5% working interest, while British Petroleum holds the remaining 28.5% interest in the field.

The field is tied back to the subsea production facilities of Mars and has been producing since June 2007.

Development of SEPCO and BP's Deimos offshore field

"Shell Exploration and Production Company (SEPCO) is operating the field with a 71.5% working interest."

The Deimos prospect was spud in June 2002 by Transocean's Deepwater Nautilus semi-submersible. It was discovered in September 2002 when SEPCO encountered with 248 true vertical net feet oil in multiple sands of the exploratory section and 287ft oil in the known producing field pays.

The field is being developed in two phases. It is currently in phase II of its development. The objective behind the phased development is to realise short-term production while gathering information on future developments to mature the Deimos prospect in an efficient timeframe.

Phase I operates at a peak capacity of 30,000 barrels of oil a day (bopd). It consists of a three-well subsea system tied back to the existing Mars tension leg platform (TLP) which has been operating since 1996.

Based on the positive results of the phase I appraisal data and production, SEPCO commenced the phase II development in April 2011.

The phase II is integrated with the ongoing development of Mars B project which involves construction of a second TLP known as Olympus to support the processing of oil drawn from eight Mississippi Canyon Blocks, including the Deimos deposit.

Mars B was approved for development in September 2010 and is expected to be operational in 2015.

Mars tension leg platform (TLP) details

The existing Mars TLP is stationed in Block 807. The TLP is 3,250ft tall and weighs approximately 36,500t. It houses a separation, dehydration, treatment facilities, a control room and an emergency response centre.

Oil from the Mars platform is transported to the Clovelly storage facility in Los Angeles via a 116m long and 18/24-inch pipeline. The gas from the platform is carried to West Delta 143 via 14-inch pipeline.

Olympus TLP development phase

Phase II development will capitalise on the SEPCO's proven concept of deep water TLPs. The Olympus TLP will be designed to process 100,000 bopd.

The Olympus TLP will be installed 3,000ft deep in Block 807 and will be located 95 miles south of New Orleans, Louisiana. The platform will have the largest tendons ever built to date, measuring 290ft long and weighing 170,000lbs. Four tendons will be placed at each corner of the platform.

The TLP will be equipped with marine instrumentation system (MIS), a computer-based system enabling the platform operators to acquire, display and record data relating to the vessel, marine and environment.

The export pipelines of the Olympus TLP will be tied to the new upcoming platform C of the existing West Delta 143 hub.

Contracts awarded regarding development of the Deimos offshore field

The American Bureau of Shipping (ABS) was appointed as the certification verification agent (CVA). Their scope of work included verification of the Olympus TLP design and fabrication and installation of the hull, topsides, piles and tendons.

"The Deimos prospect was spud in June 2002 by Transocean's Deepwater Nautilus semi-submersible."

Dril-Quip was awarded a $27m contract in October 2010 to supply drilling and production equipment, including the subsea well head equipment, production riser tieback connectors and drilling riser components.

Tendons fabrication contract was awarded in February 2011 to Frank Casing. The contract calls for fabrication of 184 individual tendon segments, as well as the qualification of welding procedures and fatigue testing.

BMT Scientific Marine Services will be providing the marine instrumentation system (MIS) to install the Olympus TLP.

Cortec will supply both single and double ball valves. The compact ball will range between two-inches and ten-inches and the check valves will have up to 15,000 psi of pressure rating.