Southern basin OKs top U.K. North Sea action

Shell U.K. Exploration & Production has won U.K. Department of Trade and Industry (DTI) approval to develop two southern North Sea gas fields. Block 44/28b Ketch and Block 49/24a Corvette fields will be developed separately with two unmanned platforms, at a total cost of £233 million ($375 million).

Feb. 16, 1998

4 min read

Shell U.K. Exploration & Production has won U.K. Department of Trade and Industry (DTI) approval to develop two southern North Sea gas fields.

Block 44/28b Ketch and Block 49/24a Corvette fields will be developed separately with two unmanned platforms, at a total cost of £233 million ($375 million).

Gary Vassie, gas director for the Shell U.K. Ltd./Esso Exploration & Production U.K. Ltd. operating venture, said, "Ketch and Corvette form part of Shell and Esso's aim to invest £4 billion ($6.4 billion) in the southern and central North Sea over the next 5 years, providing additional volume to meet our sales targets.

"Ketch and Corvette's combined peak flow of about 450 MMcfd of gas, representing about 3% of average U.K. total demand, strengthens security of supply, and furthers our ambition to be an all-around energy provider in the next century."

Meanwhile, Phillips Petroleum Co. U.K. Ltd. received DTI approval to develop Renee and Rubie oil discoveries as subsea satellites from a production semisubmersible in Ivanhoe/Rob Roy fields, operated by Amerada Hess Ltd.

Ketch plan

Ketch will be developed at a cost of £153 million ($245 million), with production slated to begin in fourth quarter 1999.

Shell/Esso said Ketch reserves are estimated at 390 bcf of gas, while gas production is expected to peak at 150 MMcfd. Produced gas will be sold separately by the gas marketing units of Shell and Esso.

Ketch was discovered in 1984 in a Carboniferous formation. The field will be depleted with seven production wells, with wellheads housed on a 12-slot, four-legged steel platform in 180 ft of water.

Ketch platform will be built by Odebrecht-SLP Engineering Ltd. The 1,200-metric ton jacket will be built at the contractor's Teesside yard, and the 1,100-ton topsides will be built at Lowestoft, U.K. Installation is scheduled for third quarter 1998.

Produced gas will be sent to Murdoch platform 17 miles away, operated by Conoco (U.K.) Ltd. From Murdoch, the gas will be sent to shore through the Caister-Murdoch export pipeline for processing at Theddlethorpe terminal.

The platform and 18-in. Ketch-Murdoch pipeline are designed to have sufficient spare capacity to allow further drilling and transportation to enable development of other prospects in the vicinity.

Corvette plan

Corvette will be developed at a cost of £80 million ($130 million), with first gas production anticipated in the fourth quarter.

Shell/Esso said Corvette output is expected to rise rapidly to a peak rate of 300 MMcfd. The two partners will market their share of Corvette gas through their own marketing units.

Corvette was discovered in January 1996 and has estimated reserves of 200 bcf of gas. It will be developed with a four-legged steel platform in 121 ft of water.

Gas from Corvette will be sent through a 20-in., 22-mile pipeline to Leman Alpha platform. From Leman Alpha, operated by Shell/Esso, gas will be exported to the venture's Bacton terminal.

Corvette platform will also be a 12-slot design, although field development is expected to require only three producers, again leaving room for tie-in of nearby developments.

The platform will be built by Heerema VOF, Leiden, the Netherlands. The topsides and jacket will weigh 1,000 tons each and will be built at the fabricator's Teesside and Vlissingen, Netherlands, yards, respectively. The platform is slated for installation in the third quarter.

Renee/Rubie plan

Phillips's Renee and Rubie finds lie on Blocks 15/27 and 15/28b, respectively, and are expected to be brought into production in the fourth quarter.

The fields will be developed in two stages. With one producer and one injector in Renee and one producer in Rubie, Phillips expects to produce a total 22,000 b/d. Twelve months later, one more producer and one more injector will be added in Renee field, taking total output from the two fields to 27,000 b/d in fourth quarter 1999.

Rubie's well will be tied back through an 8-in. oil pipeline and 2-in. service umbilical to the Renee manifold 5 km away. Renee manifold will be tied back to the Ivanhoe/Rob Roy risers 21 km away via two 8-in. oil pipelines, an 8-in. water injection line, and a 4-in. gas lift and service line umbilical.

From Ivanhoe/Rob Roy, oil will be exported through the existing pipeline to Flotta terminal in the Orkney Islands. Gas will be sent via Tartan platform, operated by Texaco Ltd., to St. Fergus terminal near Aberdeen.

Bud Chamberlain, managing director of Phillips U.K., said: "Phillips discovered Renee field more than 20 years ago in 1976. At that time, an economic development was not possible.

"Now, with existing infrastructure close to the field and new technology, we've found the way to bring these two fields on stream and are pushing ahead just as fast as possible."