Offshore Europe

Jeremy Beckman London Oil companies and contractors are racing to get new North Sea fields onstream before winter sets in. Some are meeting or even beating their targets, but there have also been a couple of delays, one of which is symptomatic of the currently depressed UK gas market. First, the success stories. Norsk Hydro's much publicized Troll Oil Field was switched on three months ahead of schedule, soon reaching peak output of 190,000b/d from eight pre-drilled wells through the

Jeremy Beckman
London

Birch onstream, but Judy/Joanne disrupted

Oil companies and contractors are racing to get new North Sea fields onstream before winter sets in. Some are meeting or even beating their targets, but there have also been a couple of delays, one of which is symptomatic of the currently depressed UK gas market.

First, the success stories. Norsk Hydro's much publicized Troll Oil Field was switched on three months ahead of schedule, soon reaching peak output of 190,000b/d from eight pre-drilled wells through the floating concrete platform.

Also ahead of time (two weeks), but on a much smaller scale, was Lasmo's two-stage subsea Birch development in UK block 16/12a. This came in £20 million under the budgeted £140 million. Three recompleted wells are currently in service under the first stage: two are producers tied to Marathon's Brae A platform 14 km away via a subsea manifold. Produced gas is also being sold to the Brae group at the same platform.

Next year a further producer and a second water injector well will be drilled, allowing output to reach 23,000 b/d and 60 mcf/d. Estimated field life currently is 10 years, but there are three other small prospective tiebacks nearby, Elm, Larch and Pine.

On the debit side, at least in the near term, is Phillips' Judy/Joanne project. The fields were set to come on line in December, four months ahead of schedule and 15% under the £765 million budget. However, Phillips' celebrations were flattened by Enron's sudden decision not to take gas from the fields until September 1997. The take or pay arrangement means Phillips will not suffer income loss: however, payments will be delayed, and associated liquids production will be affected.

Enron made its commitment to the J-block fields' supplies at a period in the UK known as the `dash for gas'. Momentarily at least, UK gas needs appear to have been wildly overestimated. The domestic spot price is down to around 14 cents/therm (not helped by successive mild winters). Production from some established fields has been restrained as a result, yet new accumulations continue to come onstream (ARCO's Gawain and Conoco's Ganymede and Calisto being the latest).

Nervous operators are beginning to shelve new developments where possible, until the situation eases. Recently suspended are Viking Fx, Hunter and British Gas' three-field Olympus complex.

No such hassles hitting oilfield developers - only technical hitches. Amerada Hess' South Scott, a 20,000b/d subsea tieback to the Scott platform, came in a month behind time due to problems with locating a production well. Statoil's 36 MM bbl Yme Field was also put back for at least one month due to delays in converting the jack-up Maersk Giant for production purposes.

Norway arrests oil decline

Once Yme does come onstream, the next phase will be to tie in the 11 MM bbl Beta East accumulation to the Maersk Giant via a hinge-over subsea template. There also other prospects nearby, says Statoil, which could boost total reserves to 90 MM bbl.

In fact a whole host of new oil developments are suddenly lining up off Norway, easing the worries of the government that currently high Norwegian oil production would nosedive after 2000.

Statoil plans to incorporate the Lunde formation into the Gullfaks development through a field drainage program: five wells are to be drilled through the Gullfaks C platform, increasing reserves by 35 MM bbl.

Saga is aiming for first oil from the 34 MM bbl Tordis East Field in block 34/7 through a four-slot subsea template tied to the main Tordis Field infrastructure. One of these slots could also be used for a producer well from the nearby H Field.

Smedvig's spec production vessel SPU 380, built by FELS in Singapore, finally looks to have a buyer. After years of deliberation, Esso has decided that this is the best medium for developing its complex Balder reservoir which comprises numerous accumulations totaling 220 MM bbl. If the development plan is approved, 15 wells will be drilled to access 170 MM bbl, with first production possible late next year. Smedvig would probably also operate the floater, as well as managing development drilling through its semisub West Alpha.

Another floater-based plan awaiting approval from the Norwegian authorities is Norsk Hydro's NK7 billion-plus Visund development. The field's 300 MM bbl of oil and 56 bcm of gas would come through 21 wells to a semisubmersible platform with 100,000b/d capacity.

Finally, Statoil's 450 MM bbl Norne Field in the Norwegian Sea (another production ship) now looks like starting up eight months ahead of plan in April 1997. Statoil believes that the earlier start will boost Norne's net value by NKr1 billion. The current development estimate has been whittled down to NKr 7.5 billion.

Foinaven shapes up for spring start

BP continues to make good headway with Foinaven, the first Atlantic Province oilfield development in the Shetlands area. McDermott MSV Norlift, acting for the first time as a dedicated reel lay ship, recently completed the first stage of pipeline installations on the field in average water depths of 500 meters.

In all 43 km of lines were laid, comprising insulated production, test, gas lift and water injection lines, allowing first oil to come out on target next spring.

Foinaven is also the site for deployment of the world's first permanently emplaced, deepwater seismic acquisition equipment (otherwise known as 4D seismic).The technique can provide time-lapse imaging of reservoir fluids. Geco-Prakla is expected to complete processing of the data prior to first oil, with a second 4D survey to be performed next summer.

Conoco has also been acquiring seismic over its West of Shetland (WoS) acreage, using more conventional 3D technology to survey a 2,260 sq km area previously covered by 2D seismic. Its drilling plans for the area include use of multi-lateral and horizontal wells.

Conoco also has a stake in BP's technically problematic WoS oilfield, Clair. An extended well test planned for this fall has now been postponed to next summer. Various delays to the drilling program would otherwise have meant continuing to operate into the rough winter season.

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