Operators mark development progress in U.K. North Sea

Anasuria FPSO is shown under tow from Tyneside, where AMEC Process & Energy Ltd. installed topsides at its Wallsend shipyard, en route to installation in the U.K. North Sea as part of development of Guillemot, Teal, and South Teal fields.

U.K. North Sea producers have started up four fields and marked progress towards development of four others.

Among recent action:

Shell U.K. Exploration & Production (Shell Expro), operating joint venture of Shell U.K. Ltd. and Esso Exploration & Production U.K. Ltd., began gas production Oct. 1 from Schooner field.
Conoco (U.K.) Ltd. started early oil production from Banff field on Block 29/2a last month, with Sedco 707 converted semisubmersible rig producing oil directly into Stena Savonita shuttle tanker.
Mobil North Sea Ltd. started production from Nevis oil and gas field last month, following a £ 60 million ($90 million) subsea development in 340 ft of water on Block 9/12.
Amerada Hess Ltd. began oil production from Fergus field on Block 39/2 last month.
Shell Expro towed Anasuria, one of the world's largest floating production, storage and offloading (FPSO) ships, out to location in Guillemot, Teal, and South Teal fields.
Conoco secured U.K. Department of Trade & Industry approval to develop Boulton gas discovery in 37 m of water on North Sea Block 44/21a.

Schooner

Shell Expro said Schooner's initial production will average 130 MMcfd and peak output will be 170 MMcfd. Schooner lies in 70 m of water on Block 44/26a and has estimated reserves of 600 bcf of gas.

Schooner was developed at a cost of £ 262 million ($393 million), with an unmanned platform connected by a 17-mile, 16-in. pipeline to Murdoch platform.

The 12-slot Schooner platform has a four-leg steel jacket weighing 2,200 metric tons and topsides weighing 1,400 tons.

From Murdoch, operated by Conoco U.K., gas enters the Caister-Murdoch System pipeline for export to the processing plant at Theddlethorpe, Lincolnshire.

Banff

Banff field reserves are estimated at 20-110 million bbl of oil.

Conoco said the idea of early production is to pin down estimated reserves more accurately and help in the decision of full scale development method.

Conoco received outline bids from a number of contractors in August for full development of the field. The company requires contractors to propose the development option and expects to make a decision by yearend.

Early production from Banff is expected to peak at 35,000 b/d of oil from two wells. The tanker has capacity to hold 750,000 bbl of oil.

Conoco said the early production phase is expected to last 6 months, while production under full field development is scheduled to begin in first half 1998.

Nevis

Nevis production was started from the southern sector of the reservoir, with estimated reserves of 50 million bbl of oil, 1.8 million bbl of condensate, and 175 bcf of gas.

Production is expected to settle at 13,500 b/d of oil and 11 MMcfd of gas. Oil and gas are exported to Mobil's Beryl Alpha platform 5 miles west for processing and transport to shore.

Nevis also will be a phased development. Early production is from two wells. As many as eight subsea wells may be required in the northern part of the reservoir to take output to 23,000 b/d of oil and 53 MMcfd of gas in 2003.

Mobil said Nevis subsea wells will be maintained with a diverless system developed jointly by Mobil and Kvaerner FSSL Ltd., Aberdeen. Modifications to Beryl A were carried out by AMEC Process & Energy Ltd., London.

Fergus

Fergus, the most southerly producing oil field in the U.K. North Sea, was developed as a single well subsea satellite of Amerada's Fife field 4 miles northwest.

Fife is being depleted by Uisge Gorm production storage and offloading ship.

Amerada said Fergus production has reached 15,000 b/d, while estimated reserves are 6 million bbl of oil.

Fife field is currently producing about 34,000 b/d of oil.

Shell/Esso FPSO

Anasuria FPSO reached the fields on Block 21/25 last month after a 2-day tow from Tyneside, where AMEC Process & Energy Ltd. installed topsides at its Wallsend shipyard.

The ship will have capacity to process 55,000 b/d of oil and 30 MMcfd of gas. Oil storage capacity is 850,000 bbl, and water injection capacity is 85,000 b/d.

Shell Expro, joint operating venture of Shell U.K. Ltd. and Esso Exploration & Production U.K. Ltd., anticipates first production from Guillemot, Teal and South Teal early this month.

The company is currently hooking up subsea equipment and plans to begin production through two wells with water injection through a third. Eight producers and four water injectors are to be completed.

Oil will be exported by shuttle tankers, and gas will be sent through a pipeline link to the Fulmar export system (OGJ, Mar. 6, 1995, p. 33).

Total reserves in Guillemot, Teal and South Teal fields are estimated at 92 million bbl of oil and 47 bcf of gas. Shell/Esso estimates development cost at £ 500 million ($750 million).

Boulton

Boulton field will be developed with a not-normally manned platform linked by pipeline to processing and export facilities on Conoco's Murdoch platform 11 km east.

Boulton gas reserves are estimated at 165 bcf. Production is expected to begin in second quarter 1998 and peak at 90 MMcfd.

The field was discovered in 1984 and will be developed with two wells. These will be drilled in mid-1997, and one will be a dual-lateral well.

The platform will have four well slots and will consist of a four-leg steel jacket weighing 450 metric tons and a 400 ton deck.

Platform fabrication will be by SLP Engineering Ltd., Lowestoft, U.K. The platform will be installed in mid-1997.

Conoco has not disclosed Boulton development cost. Interest holders are operator Conoco 46%, Lasmo North Sea plc 44.5%, and British-Borneo Oil & Gas Ltd. 9.5%. After processing, Boulton gas will join output from Caister and Murdoch fields for transmission to Theddlethorpe.