Offshore Europe

Marathon has discovered oil in tertiary sands, west of its Brae area powerbase in the Central North Sea. Well 16/6b-6 (UKCS), drilled in 360 ft of water to a TD of 7,150 ft, encountered 107 ft of net pay. It was then suspended, but will be re-entered for tests in a few months - rig availability permitting - to determine commerciality.

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Tail end of the Britannia Field bundled 7.5 km pipelines at St. Fergus following insertion into the carrier pipe near St. Fergus. They are the world's first bundles to incorporate a hot water heating system requiring an external insulation coating.


Brae area reserves extend westward

Marathon has discovered oil in tertiary sands, west of its Brae area powerbase in the Central North Sea. Well 16/6b-6 (UKCS), drilled in 360 ft of water to a TD of 7,150 ft, encountered 107 ft of net pay. It was then suspended, but will be re-entered for tests in a few months - rig availability permitting - to determine commerciality.

Sandwiched between the discovery and the Brae platform complex is Enterprise's Sedgwick Field, currently being developed jointly with West Brae as a tieback to Brae using a seven-well subsea manifold. Three of the slots are still available, until a second drilling phase starts some time in the future. Any further finds to the west could theoretically be manifolded themselves to one of these slots, unless the new reservoir proves large enough to warrant a standalone development.

Conoco, which not long ago was drawing up development ideas for its marginal Buckland oilfield in UK block 9/18a, now wants to divest its 40% stake along with other Quadrant 9 prospects Sorby and Maclure. Buckland's marketability has been advanced by an appraisal well drilled to 12,110 ft TD by semisub Borgsten Dolphin, which flowed 4,265 b/d of oil and 4.4 MMcf/d of gas from Beryl formation sandstones.

Talisman gas bound for Frigg trunkline

Gas from Talisman Energy's Ross development - recently authorized by the UK government - will be piped from the field's FPSO Bleo Helm to the Frigg trunkline system. Approval came just 10 months after the Canadian company gained BP's controlling interest in the field, located in the Outer Moray Firth. Aside from the 20 bcf of gas, 66-100 million bbl of oil could eventually be produced, starting next summer. Crude will be offloaded to a shuttle tanker.

Ten development wells are planned, with gas lift and water injection facilities extending production for at least five and a half years. The 240-meter long, 100,000-dwt FPSO, currently under construction in Japan, will be leased to Talisman by owner Bluewater. Fluor Daniel is designing the 6,000-ton topside modules, which will be built and installed by UIE, Glasgow.

Among other potential UK field developments, Shell is considering tying the Gadwall oil discovery in block 21/19 into the facilities for Mallard, itself being hooked back subsea to a new processing module on the Kittiwake platform. In the southern gas sector, Mobil is eyeing a fast-track tieback for the Malory prospect to its Galahad platform, 8 km to the east. The discovery well was completed in January, having tested over 30 MMcf/d.

Gas from this and other virgin fields nearby will be directed through Mobil's Lancelot Area Pipeline System to new compression facilities being built for Mobil at Phillips' gas terminal at Bacton. Mobil will thereby become the second third-party occupant at Bacton. Arco controls Thames Field operations there.

Gas exports from the Central North Sea are also set for a hike, following completion of the 116-mile, 27-in diameter pipeline from the Britannia Field to St Fergus, Scotland. EMC vessel Castoro Sei performed the laying in 46 days.

Esso proves up Forseti prospect

Esso Norge's decision to upgrade processing on its Balder floating production unit looks astute, following completion of exploration drilling on the Forseti prospect in Norway Block 25/8. The well encountered oil in Paleocene sands at rates varying up to 4,200 b/d. Forseti, drilled to 6,100 ft TVD, lies 4 miles north of the Balder Field, and is Esso's second find in its current campaign in this area.

Statoil plans further appraisal of its own new oil find off Yme, this time in the Beta West structure south-west of the field's main Gamma West reservoir. Although production rates have not been issued, enough is known to indicate that two wells could be tied back subsea to the template on Yme's Beta East satellite, with fluids piped to Yme's central production jackup Maersk Giant. Another exploration well was recently spudded from this platform targeting the Epsilon structure, 5 km west of Gamma West.

Northern gas grid under review

The long-hypothesized Nordic Gas Grid has moved a step closer following the signing of a feasibility study by seven Finnish, Danish and Swedish energy companies and the European Commission. This group will finance the study's budget of ECU 1.2 million, with the aim being to develop and integrate the natural gas markets in Scandinavia with those of Russia and the Baltic states, thereby securing diversified sources of supply. Environ mental impact assessment will also be conducted of

the expanded market. Work will be performed by a consultancy conglomerate headed by Tebodin of The Netherlands.

Independently, Neste and Gazprom have set up a joint venture to study the route for a North European pipeline linking Russian natural gas to central Europe through Finland. North Transgas Oy will formulate the route options by late 1998. The pipeline could cross the Baltic Sea to Germany either through Finland or Sweden.

On the ever-flourishing Norwegian gas development front, Statoil has contracted McDermott-ETPM to lay the 697-km long, 42-in. diameter Aasgard Transport Pipeline from the Aasgard B facilities off Mid-Norway to the terminal at Kaarstoe. A fifth tensioner will be added to the lay vessel LB200 to increase tension capacity for the unusually heavy pipes. Maximum wall thickness will be 32.3 mm, one of the thickest yet for a large-scale welding operation.

Statoil has also issued provisional plans for exploiting associated gas from the Heidrun and Norne oilfields. Two new export pipelines could be installed carrying 2 bcm from these fields to the Aasgard export riser base, from there mingling into the main Aasgard transport line.

Buyers move in for old platforms

Conoco Netherlands is hopeful of clinching a sale shortly for its Kotter and Logger platforms. Although production will wind down late this year, the decks and production facilities are said to be in good shape for re-use elsewhere (but not by Conoco, which will be exiting the Dutch sector). Both platforms have been in service since the mid-1980s, producing close to 100 million bbl combined.

Also in the Dutch North Sea, heavy lift vessel has been removing two gas production platforms for operator Wintershall, K10 Charlie and K13 Bravo, in a series of lifts totaling over 2,500 tons. The structures will be transported to Swan Hunter's yard on Tyneside UK for dismantling and recycling, where possible.

Copyright 1997 Oil & Gas Journal. All Rights Reserved.

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