Statoil has filed a development plan for Heidrun North in the mid-Norwegian Halten Bank, and hopes to start production drilling this August.

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Statoil eyes new phase of gas projects

Statoil has filed a development plan for Heidrun North in the mid-Norwegian Halten Bank, and hopes to start production drilling this August. The 25 million bbl, gas-capped reservoir lies northeast of the main Heidrun Field, which came onstream in 1994 through a tension leg platform (TLP) and currently produces 210,000 b/d of oil. Tying in production from Heidrun North will allow that plateau rate to be sustained for another four years.

Eleven development wells are envisaged for the new NKr 5.5 billion project, including an injector which will be tied back to the TLP. A new gas export line will also be laid, connecting to the Åsgard area trunkline (due to enter service this October). Further pieces are also falling into place on the Åsgard production complex. The 860,000-bbl capacity Åsgard C condensate storage vessel, under construction by Astilleros Espanoles in Bilbao, should be ready to receive first supplies from the Åsgard B production semisubmersible in July.

The semi currently is nearing the end of an extensive equipment test program. This has revealed more widespread faults and deficiencies than had been anticipated, pushing up the estimated cost of the floater to NKr 12.28 billion, compared with last October's figure of NKr 11.414 billion. Statoil claims, however, that this is still within the project's overall investment framework.

The Halten Bank's next major development will be Halten Bank South, embracing the Kristin, Lavrans, Tyrihans South and North structures, and possibly also Erlend and Ragnfrid. Statoil's latest estimate of total recoverable gas is 100-150 bcm, roughly on par with Sleipner West in the North Sea. Combined condensate/oil reserves are put at 600-900 million bbl, which equates to the those under development at

Around that time, Statoil may also decide to terminate operations at Yme in the North Sea, where average daily output fell unexpectedly last year to 27,000 b/d. This is Norway's smallest field to be developed with a standalone platform - in this case, a production jackup. The platform may end up doing similar duty on another field, with Norwegian independent DNO rumored to be one of the interested parties.

Elsewhere in the Norwegian sector, Esso has contracted ABB to provide three subsea production and two subsea water injection systems for its Ringhorn development. This involves tying back various reservoir pools to the floating production, storage, and offloading vessel on the Balder Field. Construction delays to this vessel caused serious delays to the production schedule. Esso is maintaining its lawsuit against the original contractor Smedvig, although the figure claimed has recently eased back from $560 million to $400 million.

DONG targets upstream expansion

State-owned Danish oil company DONG is purchasing Denerco's 50% interest in local license operator Danop for $6.5 million. Danop will thereby become a wholly-owned subsidiary of DONG. The latter helped establish the company in 1985 to participate in Danish exploration and production licenses in a technical capacity (without taking equity interest). It has since operated six exploration wells in the Danish sector, including the Bertel and Siri North discoveries, and it currently operates nine offshore exploration licenses. Danop, which has a staff of 52, will provide DONG with the technical resources it needs to expand its upstream business. Building a position outside Denmark - particularly the Norwegian CS - is one of its stated targets.

Minimal cost, minimal platform for Skiff

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This schematic shows the lightweight Trident platform, developed in-house by Shell UK Expro, which will make its debut on the Skiff Field.
Click here to enlarge image

Shell UK Expro has chosen an in-house concept for its new platform for the Skiff gas field development in the southern North Sea. The Trident design, developed by Shell's local project team in Lowestoft over a 12-month period, is a minimal facility structure weighing only 400 tons, which allows it to be installed by a drilling rig. Fabrication will also be performed locally by KYE. Shell believes the platform could be delivered for only £5 million, which if true, would open up development of a host of other marginal fields. The overall cost for this project will be £70 million, including a new 12-in., 11-km pipeline to connect Skiff with Shell's Sole Pit Clipper complex, offshore the Norfolk coast. Four gas production wells will be drilled, and underbalanced drilling techniques will be employed.

In the central UK North Sea, Kerr-McGee has reportedly identified 70-100 million boe from its three-well exploration and appraisal program on the Leadon prospect, 15 miles north of Gryphon (where it operates an FPSO). In the same sector, production on the Enterprise-operated Pierce Field was recently shut in for 10 days for a de-bottlenecking program. Planned modifications to the FPSO Berge Hugin should allow pro duction to be raised 20% to 65,000 b/d. The field came onstream in February 1999.

Enterprise has also strengthened its position on the Atlantic Margin through buying Arco's Irish exploration interests, and hopes to assume operatorship soon of West of Shetlands Tranche 4, located 100 km north of the undeveloped Clair oilfield.

Also in this region, geotechnical drilling contractor Seacore has just completed a seabed survey in the Hatton Bank, the Bean Basin (west of Ireland), and offshore The Faroes for the British Geological Survey's Petroleum and Marine Geology Department.

The deepest site required a drill string over one mile long (deployed from the geotechnical drilling vessel M/S Bucentaur), which extended through waters 1,566 meters deep and a further 71 meters into the seabed. Altogether, 14 cored boreholes were drilled, the aim being to identify and age numerous beds and unconformities in the substrata that had been selected from previous surveys.

Clyde advances Q/4 block developments

Offshore The Netherlands, Clyde has been awarded a production license for block Q4 in the southern sector, which contains its two recent gas discoveries Q/4-A and B. These will be developed in phases - the former will be tied back to Clyde's P/6 processing complex using an unmanned satellite platform, with first production possible by the end of this year. Q/4-B will be tied back next year to the Q/4-A platform, but the extent of the facilities upgrade has reportedly not yet been determined. Combined reserves from the two fields are put at 180 bcf. Clyde has also been drilling recently in block P/6-9, targeting a gas prospect within Bunter (Triassic) sandstones.

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