The Magnolia field is located approximately 180 miles south of Cameron, Louisiana, US, in Garden Banks blocks 783 and 784 in the Gulf of Mexico. ConocoPhillips, as operator, holds a 75% working interest in the field with Ocean Energy owning the remaining 25%. In 2003, Ocean Energy merged with Devon Energy, so, 25% is now owned by Devon Energy.
The field began production in 2004 and the initial development was completed in 2006. Magnolia reported an average production of five million barrels per day of crude oil, ten million cubic feet per day of natural gas and one million barrels per day of natural gas liquids in 2008.
Magnolia deepwater oil and gas drilling
The Magnolia field was discovered with the first well drilled by ConocoPhillips’ Deepwater Pathfinder in May 1999 when it drilled on Garden Banks Block 783 in 4,700ft of water as part of a five-year, $400m deepwater drilling programme. The well, drilled to a depth of 16,868ft, encountered hydrocarbon-bearing sections of 150ft to 200ft net.
This was followed by the Magnolia GB 783 No2 appraisal well, a 6,000ft westerly step-out from the discovery. This was drilled to a total depth of 17,435ft. The well encountered oil-bearing sand in excess of 400ft net, with 300ft net in one continuous unit.
After logging operations were completed, the well was sidetracked 3,000ft southwest to provide an additional penetration of the main pay sand. The sidetrack encountered 400ft net of oil-bearing sand. It has been estimated that in total, the field could yield more than 150 million barrels of oil equivalent in future production.
Tension leg platform
The Magnolia field was developed by a tension leg platform (TLP), installed in 4,700ft of water, a record depth for this type of floating structure. This is located approximately 30 miles from the existing infrastructure, enabling Magnolia to be a regional off-take point for future developments or third party tie-ins located in the southeastern Garden Banks area.
All previously drilled wells were converted to production wells as part of the eight wells required to bring the Magnolia Field into full production. Initial estimates had put the total development bill at $600m.
ABB Lummus Global Americas of Houston was awarded the contract for design, procurement, project management and construction services for the TLP hull and associated systems. This innovative deepwater hull consists of four circular columns connected at the bottom by rectangular pontoons. At the base of each column, a pontoon extends outwards to support two tethers, which are connected to pile foundations on the seabed. The TLP hull was constructed at the yard of Samsung Heavy Industries in South Korea.
Alliance Engineering of Houston was awarded the contract for the topsides’ engineering, procurement and project management services.
The topsides design incorporates state-of-the-art lightweight design technology, which reduces costs and preserves flexibility in production operations.
The Magnolia TLP will be connected to the Shell-operated platform hub at Garden Banks 128, located 50 miles away, by means of two pipelines to Shell’s Enchilada platform.
EMCÉ BV provided the winches for the installation of platform. Accommodation units were provided by Duffy & McGovern Accommodation Services.
Magnolia oil and gas project details
The design capacity of the production facilities is 50,000 barrels of oil per day and 150 million standard cubic feet of gas per day. The platform is also be fitted with completion rig.
The Magnolia TLP is connected to the Shell-operated platform hub at Garden Banks 128, located 50 miles away, by means of two pipelines to Shell’s Enchilada platform.
The 16in natural gas pipeline is constructed and owned by Shell Gas Gathering, and has a 275 million cubic feet per day capacity. It connects into the Shell-operated Garden Banks Gas Pipeline System, which transports the gas to a variety of pipelines linked to onshore locations.
The 14in oil pipeline was constructed and owned by Shell Pipeline Company and has a 75,000bpd capacity. It is connected into the existing Auger pipeline system.