U.K. record well tops NW Europe action

BP Exploration Operating Co. Ltd. is once again pushing the limits of extended reach drilling in Wytch Farm oil field in southern England.

A well currently drilling ahead there has passed the current world record for horizontal displacement of 8,061 m and is expected to have a final horizontal reach of 10,000 m.

Meanwhile, Amerada Hess Ltd., Shell U.K. Exploration & Production, and Texaco North Sea U.K. Co. have announced a plan for joint development of Bittern and Guillemot West finds with a floating production system.

Wood Mackenzie Consultants Ltd., Edinburgh, reckons that Ormen Lange gas discovery, made on Block 6305/5 off central Norway by Norsk Hydro AS, may be Norway's largest in oil equivalent terms in the past 15 years.

Texaco has also begun production of gas and liquids from the North Sea's first high-pressure/high-temperature field. This is Erskine, which straddles U.K. North Sea Blocks 23/26b and 23/26a.

Also, Norway's state firm Statoil is planning to develop three fields as satellites of existing Norwegian North Sea infrastructure: Glitne, Theta West, and Huldra.

Wytch Farm

In Wytch Farm, BP is depleting an offshore reservoir through extended reach drilling from onshore drilling sites around Poole Harbour, Dorset (OGJ, Jan. 3, 1994, p. 30).

On Nov. 3, the operator said it had reached 8,388 m horizontal displacement. The previous mark was recently set by Phillips Petroleum Co. in China, then passing a 1995 record of 8,035 m set by BP at Wytch Farm.

BP has drilled 13 extended reach wells to date at Wytch Farm. The current well is designated M11 and was spudded in May. The operator expects to reach target depth in January 1998.

The M11 well is anticipated to recover 3-8 million bbl of oil. The field comprises two main reservoirs: onshore Bridport, developed with conventional wells; and offshore Sherwood, depleted with long reach wells.

Bridport has estimated reserves of 30 million bbl of oil, Sherwood has estimated reserves of 420 million bbl of oil, and the undeveloped Frome reservoir has estimated reserves of 4 million bbl of oil.

Frank Allen, BP's drilling superintendent at Wytch Farm, attributes the extended reach record to being able to drill more than 7,400 m open hole before casing.

Bittern/Guillemot West

Amerada, Shell, and Texaco have decided on a shared floating production, storage, and offloading (FPSO) solution for development of Bittern and Guillemot West.

Bittern discovery straddles Blocks 29/1a and 29/1b, operated by Shell and Amerada, respectively. The find was known informally as Razorbill and Abbot, respectively, by the two firms before joint development was agreed.

Guillemot West reaches into five blocks: Texaco's Blocks 21/24 and 21/29a and Shell's 21/29b, 21/25, and 21/30.

Field unitization has not been agreed, but interest owners in Bittern and Guillemot West blocks are Amerada, Shell, Esso Exploration & Production U.K. Ltd., Enterprise Oil plc, Deminex U.K. Oil & Gas Ltd., Hardy Exploration & Production Ltd., Texaco, and Talisman North Sea Ltd.

The companies have not disclosed estimates of reserves for the finds, saying it is "too early." They intend to submit a development plan to the Department of Trade and Industry in the near future.

Oil from Bittern and Guillemot West is intended to be exported by shuttle tankers. Gas from the fields will be exported through a pipeline link to the Fulmar trunkline to shore.

The operators say a team approach will be adopted for the development: the FPSO will be managed by a joint team, with Amerada as duty holder; Bittern subsea development will be led by Shell; and Texaco will lead the subsea development team for Guillemot West.

Ormen Lange

Norsk Hydro's Ormen Lange discovery was made with 6305/5-1 well, a rank wildcat in the deepwater Moere basin off central Norway, only last year licensed for exploration.

Wood Mackenzie says Ormen Lange was found in Paleocene sandstone, with pay zones at 2,700-3,027 m. No gas-water contact was encountered.

The analyst says that, while the discovery well was not tested, "preliminary reserves estimates suggest that around 3.5 tcf of gas can be considered to have been proven as a result of the first well, but there is substantial upside potential, and a likely reserves figure could be about 10 tcf."

Norsk Hydro is expected to drill two appraisal wells in Ormen Lange in 1998, and BP Norge is planning to drill into an extension to the south onto a neighboring block next year also.

"In the light of the current projected level of gas sales from Norway, which could reach a plateau of around 80 billion cu m/year around 2005, it is difficult to envision any development of Ormen Lange proceeding within the next 20 years,"said Wood Mackenzie.

Erskine

Texaco brought Erskine gas/condensate field into production on Nov. 4, following a £290 million ($465 million) development (OGJ, Nov. 10, 1997, p. 46).

Erskine was developed with an unmanned platform from which multiphase output is piped to Lomond platform 30 km away for processing and export (OGJ, Mar. 17, 1997, p. 36).

Development drilling will continue until six production wells have been completed in October 1998. Then peak production of 120 MMcfd of gas and 29,600 b/d of condensate is anticipated.

Erskine has estimated reserves of 330 bcf of gas and 75 million bbl of condensate. The reservoir lies at a depth of 15,000 ft in Jurassic sandstone. There the pressure is 14,000 psi and the temperature 340° F.

Statoil plans

Statoil is planning a joint development of Glitne and Theta West oil finds on Norway's Blocks 15/5 and 15/9, respectively, north and west of Sleipner West field. Statoil aims to submit a development plan to the government next year, with first production anticipated in October 2000 at the earliest.

Glitne lies 40 km northwest of Sleipner A platform in 110 m of water and has estimated reserves of 50-60 million bbl of oil.

Theta West lies 8 km north of Sleipner A in 85-90 m of water. Statoil says its reserves figure remains to be clarified.

Svein Loening, project manager for Glitne and Theta West, said, "Glitne will be a satellite to Theta West or Sleipner A. We could opt for a small wellhead platform or subsea wells tied to a processing installation in Theta West or on Sleipner A."

Statoil is looking to submit a field development plan for Huldra discovery to authorities in December.

The operator says licensees want gas from Huldra to be sent by pipeline to Kollsnes treatment plant near Bergen and Huldra condensate to be sent to Veslefrikk B platform for processing and export.

Huldra lies on Blocks 30/2 and 30/3 near giant Troll field. It has estimated reserves of 675 bcf of gas and 45 million bbl of oil and condensate.