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Four UK oil and gas discoveries have been announced, lifting the limbo that had settled over the exploration sector. However, even the most significant find - west of Shetland - was broadcast without fanfare. Operator Conoco appeared to be preoccupied with the impact on its US public share offering. It was left to partner British-Borneo to declare "a significant oil and gas column" encountered by well 204/14-1 prior to attaining total depth. The well was appraising the Suilven structure,

Jeremy Beckman
London

Suilven appraisal revives UK hopes

Four UK oil and gas discoveries have been announced, lifting the limbo that had settled over the exploration sector. However, even the most significant find - west of Shetland - was broadcast without fanfare.

Operator Conoco appeared to be preoccupied with the impact on its US public share offering. It was left to partner British-Borneo to declare "a significant oil and gas column" encountered by well 204/14-1 prior to attaining total depth. The well was appraising the Suilven structure, discovered by BP in adjoining waters in 1995.

Reports suggest up to 500 million bbl could be in place across the two licence areas. Hopes are high for another second-hand announcement from the nearby Onslow prospect, which the semisubmersible Sovereign Explorer was due to start drilling this month.

British-Borneo's statement also cited a gas discovery called Laggan in Shetland area block 206/1. This and Suilven's associated gas will be noted by the multi-company Aurora team seeking to harness stranded west of Shetlands gas to the UK's benefit.

In the Central North Sea, well 21/12-3 encountered oil seven miles north of Shell/Esso's Kittiwake Field in 280 ft of water. The well, drilled to a total measured depth of 9,670 ft, tested 33° API oil at 8,200 b/d on a 32/64-in. choke. It has been suspended pending further evaluation as a possible subsea tieback to the Kittiwake platform.

Dana Petroleum reported a gas discovery close to the Beta Field on the UK/Netherlands median line. Well 44/24a-5, operated by Fina, tested at 41 MMcf/d. The find is being incorporated into development planning for this licence, which also includes the Orca Field. Also in the Southern North Sea, Enterprise Oil announced that well 49/23-9 on Amoco's Bell prospect tested 70 MMcf/d, and will likely be brought into production next year, again tied back to existing infrastructure.

BP Norge feted; Hydro frustrated

BP Norge is claiming that its A21 well, drilled from the Gyda platform in June, could be the world's hottest and deepest extended reach well to date. During its 8,417 meter journey to a structure in the southern part of the Gyda Field, it reached a total depth of 4,200 meters and generated wellstream at temperatures of 165°C. These values comfortably exceed BP Norge's previous North Sea record for a deviated well, also on Gyda South.

Northwest of Gyda, BP also confirmed a 30 million bbl oil pocket in late Jurassic sandstone, following appraisal of a 1983 discovery by the previous block operator, Elf. No production testing was deemed necessary. A development plan may be submitted next year, as a subsea satellite either to Gyda ot to the Ula platform, 15 km to the northwest.

In the much deeper waters of the Voering Basin, BP has reportedly confirmed sizeable gas quantities during exploration of the southern extension of the giant Ormen Lange gas field. Norsk Hydro is also busy on the main northern section - reserves on the structure have been posited at around 600 bcm.

Further north in the Barents Sea, however, Hydro's plans to drill a 50-day appraisal well in the Snoehvit Field's thin oil zone have been thwarted. The semisubmersible West Delta was upgraded in readiness at a site near Bergen, but the Norwegian Petroleum Directorate vetoed the third generation rig as being ill-equipped, should temperatures fall below minus 10°C. Norwegian protest groups had argued this point in their attempts to block drilling, claiming that the prolific fishing/seabird area was poorly equipped for oil spill response.

Hydro may now be forced to postpone operations until 1999. Snoehvit's oil zone is thought to hold 75 million bbl of oil. Hydro and Statoil have been eyeing a unitized development embracing Snoehvit and the nearby Albatross, Alke, and Askeladden fields.

Pipeline passage unblocked

At the ONS in Stavanger, Norwegian and British energy ministers signed new accords on pipeline networks. The first concerned revision of the Frigg Treaty, established in 1976, which allowed gas from the Frigg Field on Norway's side of the North Sea median line to be piped to St Fergus in Scotland. However, as the UK's own offshore gas sector began to flourish, an impasse developed over continued imports of Norwegian gas once Frigg had depleted.

Resolution of the dispute will allow operators such as Norsk Hydro to pursue development of marginal gas fields like Skirne and Vale through its Heimdal complex. A second framework agreement between the two nations should speed up approval for new platform-connecting pipelines or spur line in the median line area. One such is planned between Heimdal and Frigg, with a probable annual throughput of 10 bcm.

Another proposed new line would be firmly within Norwegian jurisdiction. Statoil has teamed up with BP to examine safer ways of disposing of carbon dioxide. One idea is to pipe carbon dioxide extracted at the Karstoe plant on Norway's west coast 240 km to the Sleipner area of the North Sea, where it would be injected into a deep saline formation.

Shell "abandons" Kingfisher

Marathon's Brae complex is becoming a pit-stop for third parties. Last year Enterprise sold its joint share of Sedgwick, just as the fast-track project was coming onstream via a tieback to the Brae A platform. Enterprise claimed it wanted to focus on bigger UK assets like Nelson.

Now Shell wants out of Kingfisher - a tieback to Brae B - a mere 10 months after first pro duction. Shell came to the official conclusion that the field was not strategically important, being remote from its infrastructure strongholds.

Kingfisher is a high pressure field currently producing 30,000 b/d of oil and condensate and 138 MMcf/d of gas. Many papers have been presented on its novel high integrity pipeline protection system, which can shut off production should wellhead pressure surge. It could be that Shell viewed this system all along as a test case for bigger things - its Shearwater development, for instance, on which 15,000 psi subsea trees are currently being qualified.

Copyright 1998 Oil & Gas Journal. All Rights Reserved.

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