Otis Field Development, Gulf of Mexico

Otis is a deepwater discovery located in Mississippi Canyon block 79 in the Gulf of Mexico. The field lies in a water depth of approximately 3,800ft.

The area is being developed by LLOG Exploration, which owns a 70% interest, and Ridgewood Energy-managed entities, including Riverstone designated affiliates, which hold the remaining stake in the field.

LLOG Exploration, a deepwater exploration company founded in 1977 in Louisiana, operates extensively in the Gulf of Mexico with interest in 120 blocks, which are mainly located in Mississippi Canyon, Green Canyon and South Timbalier.

Otis field discovery and development

The Otis field was discovered by Sevan Louisiana deepwater drilling rig, which began drilling of an exploration well in the deepwater Otis prospect in June 2014.

Well test results indicated the presence of hydrocarbons in October 2014 when the exploratory well found 70ft of net hydrocarbons in a Miocene reservoir containing a high yield of gas condensate. This discovery was further confirmed by an appraisal sidetrack.

The Otis field will be developed as a subsea tie-back to LLOG Exploration’s existing Delta House floating production system (FPS). Offshore installations for the Otis field development are expected to be completed in early 2016. Deepwater rigid reel Lay Vessel 105 (LV 105) is being used to carry out the tieback installation.

Delta House FPS details

Delta House is an FPS moored in the water depth of 4,500ft in the Mississippi Canyon 254 region. It is LLOG Exploration’s second four-column FPS.

The four-column semi-submersible system is designed to assimilate production from a number of nearby fields. It is 296ft-tall, weighs 18,600t, and is powered by three gas turbine generators of 4.8MW each.

The FPS has a capacity of 100,000 barrels of oil a day, as well as 240 million cubic feet. The first production from the Delta House FPS deployed on the Delta House Development was achieved in April 2015.

LLOG Exploration operates the Delta House FPS along with its joint venture partner Blackstone Energy Partners. Ridgewood Energy and its entities including Red Willow Offshore, Calypso Exploration, Deep Gulf Energy II and Houston Energy are co-owners of the FPS.

Contractors involved with the Otis field development

LLOG placed a three-year charter contract with Sevan Drilling for the Sevan Louisiana drilling rig in April 2013.

McDermott was awarded the contract for developing the Otis field as a subsea tieback. The scope of work includes project management, engineering and pre-commissioning. It will be responsible for fabricating and installing a 75,000ft-long insulated rigid flow-line and an insulated steel catenary riser (SCR) with associated pipeline end termination (PLET) and jumper.

McDermott’s new spoolbase facility in Gulfport, Mississippi, will assemble and fabricate the flow-line and the SCR.

Exmar Offshore was awarded a contract to design the hull and deck structure of the Delta House FPS. Exmar was also contracted to oversee the construction of the hull at Hyundai Heavy Industries’ yard in Korea.