KG-DWN-98/1 (KG-D6), Bay of Bengal, India

The 8,100km² block KG-DWN-98/l (KG-D6) lies in the Krishna-Godivari basin, Bay of Bengal, on India's east coast. The seabed slopes sharply causing water depths to vary between 700m (2,297ft) and 1,700m (5,577ft). The field is operated by Reliance Industries (90%) on behalf of Niko Resources (10%). Block reserves have been put at about 14,000bn cubic feet of gas and about 140m barrels of oil.

The first three discoveries (Dhirubhai-1, Dhirubhai-2 and Dhirubhai-3) have estimated gas reserves of 7-8trn cubic feet. In March 2003, the deepwater rig Discover 534 discovered Dhirubhai-4, with in-place gas volumes of 1,700bn standard cubic feet (bcf). And in February 2006, Reliance announced that it had encountered the thickest hydrocarbon column to date, the MA-2 well (about 2km from the MA-1 discovery well) reaching a depth of about 3.6km and penetrating a gross hydrocarbon column of 194m consisting of 170m of gas/condensate (53° API) and 24m of oil (42° API).

The project is expected eventually to cost more than $10bn. Production of crude oil started in September 2008 from the block’s MA field, while production of gas from the Dhirubhai-1 and Dhirubhai-3 fields is scheduled to start by late 2008/early 2009. Initial rate of production from the MA field is about 5,000bpd and is expected to reach its peak rate of 40,000bpd by about mid-2010, while D1 and D3 are forecast to reach 2.8bcfd within the first year of operation, although there is flexibility to raise this to 4.2bcfd.

Development

The work has included development of at least 18 production wells, with subsea equipment, pipelines, a riser platform and an onshore terminal. In January 2006, Reliance awarded US-based Bechtel the overall EPCM contract for the project.

Subsea equipment

This fast-track development has involved one of the biggest and most complex underwater installation campaigns ever. Aker Kvaerner Subsea was responsible for the complete subsea production system in a $400m Engineering, Procurement and Construction (EPC) contract.

Because of the high flowrate potential, the 55t trees have a 127mm and 178mm bore. The subsea contract was based on 19 subsea trees tied into six six-slot production manifolds weighing 225t each. The longest tieback is 6.4km. From these manifolds, production flows through in-field pipelines to the 370t Pipeline End Manifold (PLEM). The longest manifold tieback is 6.8km. The PLEM has been designed to accept additional pipeline tie-ins.

The umbilical distribution hub weighs 170t and there are three 110t (each) subsea distribution assemblies. The 32 lengths of steel-tube umbilical total 101km and there is also 57km of electric power cable. Finally, there is a comprehensive subsea control system.

A pair of 10km 24in production lines link the PLEM to a Control and Riser Platform (CRP) located in 100m of water. Compression facilities will ease the anticipated reservoir pressures drop two to three years after start-up. Gas export will use three 24in lines running 25km from the CRP platform to shore where gas will be routed to the offshore terminal at Kakinada. The MEG used to prevent hydrates will be reprocessed in a closed loop in a system provided by Aker Kvaerner.

KG-DWN-98/L (KG-D4) platform jacket

The platform jacket was manufactured as part of an engineering, procurement, construction, and installation contract by J Ray McDermott. The 9,015t jacket was built at J Ray's Morgan City, Louisiana, fabrication facility, with the piles and topsides being fabricated at the company's Jebel Ali facility in the United Arab Emirates.

At Pascagoula, Mississippi, the jacket and cargo barge were loaded onto a Fast Transport Vessel (FTV) for a 46-day journey through the Suez Canal to the marine and fabrication base on Batam Island, Indonesia.

DeepOcean won a $166m contract three-year contract to provide a multi-purpose subsea support vessel and related services. The REM Etive has been deployed under a commercial agreement between DeepOcean and TS Marine to support development.

The Etive is being used for installation, commissioning, and inspection / maintenance / repair, having two work-class ROVs, crane capacity, and an active heave compensated winch system.

As of June 2008, Reliance was carrying out conceptual studies for the development of another eight natural gas discoveries near the D1 and D3 gas fields. The satellite discoveries are likely to be tied to the production facilities for D1 and D3, it said.