STORM TRIMS OIL FLOW IN NORTH SEA

Winds gusting to 100 mph in the northern and central North Sea last week shut down several oil fields that rely on ships for production or transportation.

Progress on the Draugen field development project off Norway also was interrupted.

North Sea production and development operations and plans had hit a fast clip before the storm blew in.

Norwegian offshore oil production continued its record breaking run with an average 2.34 million b/d last November. That was up 47,000 b/d from October's record volume (OGJ, Dec. 28, 1992, p. 24).
Tests on wave performance of the Ekofisk field tank platform are under way in Canada on behalf of Phillips Petroleum Co. Norway. Phillips commissioned the Institute of Marine Dynamics (IMD) to carry out three sets of tests on a scale model of the Ekofisk tank unit, which has been the subject of safety concerns (OGJ, Nov. 30, 1992, p. 34), and connected platforms.
An accommodation platform for Claymore field in U.K. Block 14/19 is to be installed to improve safety and long term economics of the field. Operator Elf Enterprise Caledonia Ltd. currently houses workers on the Claymore A production platform and a floating accommodation unit moored alongside.
A group led by Marathon Oil U.K, Ltd. cut a combined 350 ft of net hydrocarbon section in two zones at a Brae area appraisal well in U.K. Block 16/7A. Neither of the zones has seen development in the field. Production tests of a gas/condensate pay are under way.
Development drilling is picking up off Denmark, with a total of 17 wells expected to be completed in 1992 when final figures are in, up from 13 in 1991. A peak of about 30 development wells/year is expected in the mid-1990s, said County NatWest WoodMac, Edinburgh analyst.

STORM REPORT

Worst hit by the big storm was Norway's Den Norske stats oljeselskap AS (Statoil), which had its Statfjord and Gullfaks field on reduced production since Jan. 8. The limit to storage in both fields, which produce an average 700,000 b/d and 470,000 b/d respectively, meant production was reduced to 10% of normal levels by Jan. 13.

Also affected was Snorre field, which produces 120,000 b/d for Saga Petroleum AS. Snorre oil is shipped via the Statfiord A platform.

A spokesman said Jan. 13 production from the three fields would cease early Dec. 14 if the weather did not improve. He said weather forecasts warned that conditions would not improve in time to prevent shutdown.

Mobil North Sea Ltd. halved oil production to 55,000 b/d from Beryl field Jan. 10. A spokesman said Beryl storage capacity was large enough to maintain production at that level until the weather broke.

Tankers were standing by to begin loading. Mobil hoped for a change in the weather Jan. 13. Beryl gas production was unaffected at 265 MMcfd, sent by pipeline to St. Fergus, Scotland.

BP Exploration Operating Co. Ltd. lost production from two central North Sea fields, Buchan in Block 20/5a and Donan in Block 15/20a. A spokesman said the risers were pulled on both fields Jan. 10.

Depending on the weather, BP hoped to have both fields on production by Jan. 16. Buchan was producing 15,000 b/d of oil, while Donan, which uses the Seillean production vessel, was flowing 12,000 b/d.

Shell U.K. Exploration & Production, operator for the Shell/Esso U.K. Ltd. combine, lost production intermittently from Kittiwake field in Central North Sea Block 21/18a beginning Jan. 10. Recent production averaged 22,000 b/d.

Norske Shell AS had to postpone towing of the Draugen topsides from Stavanger to the deepwater site at Vats, where further installation work and commissioning will take place.

The topsides will form part of a concrete monotower development on Norwegian Block 6407/9, due on stream this autumn. Tow-out had been scheduled for Jan. 10. Shell said the operation needs a 48 hr weather window with winds of less than 15 mph.

NOVEMBER PRODUCTION

The hike in Norwegian oil flow was largely due to increased production from Snorre field. Figures compiled by WoodMac show Snorre production reached 100,000 b/d, while Gullfaks field production climbed to a high of 488,000 b/d.

British oil production, including onshore fields, remained above the 2 million b/d mark, rising 45,000 b/d to reach 2.06 million b/d for November. All U.K. fields are operating normally at or near capacity, WoodMac said.

Danish North Sea oil production fell to 163,000 b/d in November from 164,000 b/d in October. Dutch production fell too, by 1,000 b/d to 30,000 b/d in November.

Norwegian gas flow was down to 2.57 bcfd in November from 2.76 bcfd in October. U.K. gas demand, meanwhile, was 7.2 bcfd in November, up 1 bcfd from October. Only 6% of U.K. November demand was met by Norwegian gas, compared with 9% in the same period last year.

Dutch offshore production rose from 1.66 bcfd in October to 2.05 bcfd in November, partly due to Markham field coming on stream at an average 77 MMcfd.

Danish gas production fell 14 MMcfd to 406 MMcfd in November, while Irish flow fell 25% from October to 179 MMcfd.

EKOFISK TEST

The $380,000 Ekofisk tank platform test program is being carried out at MID's St. john's, Newf., laboratory. Researchers are measuring wave impact loads, velocity of overlapping water, and wind profiles of the complex.

First tests were carried out late last month. A second series of trials was to begin last week, while the third round of tests will be conducted early in February. A final report will be presented to Phillips later that month.

Phillips also is studying alternatives for relocation of the Ekofisk oil and gas processing and transportation facilities (OGJ, Jan. 11, p. 28.) The Norwegian Petroleum Directorate (NPD) set a July 1 deadline for submission of Phillips' recommendations.

The NPD said Phillips must shut down Ekofisk production if subsidence around the tank platform reaches a point at which a theoretical 100 year wave could spill over the tank's barrier.

CLAYMORE PLATFORM

Elf said the new Claymore platform will enhance safety by Separating crew quarters from the production unit. It will also improve operational economics by removing the weather contraints of flotel operation and the costs of helicopter transfers.

Although the capital outlay will be high, he said, costs will be reduced long term, delaying the date at which field operation becomes no longer viable. The company also spent f:60 million ($90 million) installing subsea isolation valves in the field after the Piper Alpha platform explosion of 1988.

The L70 million ($105 million) contract for engineering, procurement and construction of the new platform went to SLP Engineering Ltd., Lowestoft, U.K. The contractor will build the 4,600 metric tons topsides at its Lowestoft yard and the 6,235 metric tons jacket at Teesside, U.K.

The new platform, to be linked by a 100 m bridge to Claymore A, will house 250 persons, communications facilities, an additional emergency control room, and a temporary safe refuge. Installation is scheduled for spring 1995.

Claymore, in operation since July 1977, produces 55,000 b/d of oil. It also processes 30,000 b/d from the subsea Scapa satellite field and 130,000 b/d from six fields operated by other companies.

Oil moves from Claymore to the Elf terminal at Flotta, Orkney Islands.

MARATHON APPRAISAL

Marathon's 16/7A-B20 Beinn field appraisal well flowed 30 MMcfd of gas and 4,000 b/d of condensate with 4,300 psi flowing tubing pressure through a 1'/2 in. choke from middle Jurassic sandstone. The well cut about 200 ft of net middle Jurassic pay at 14,300-600 ft.

Marathon plans extended production tests.

The well also found upper Jurassic pay in what Marathon termed "good quality reservoirs" holding gas, condensate, and oil. Marathon said there is about 150 ft of net pay at 12,460-860 ft that will require further delineation. It plans to drill an appraisal well, 16/ 7A-B21, from the Brae field B platform in the first quarter of this year to evaluate this zone.

Well 16/7A-B20 was drilled from the Brae B platform in North Brae field, 155 miles northeast of Aberdeen.

Marathon is operator for the Brae group with a 38% interest. Its partners are Britoil plc 20%, Bow Valley Petroleum (U.K.) Ltd. 14%, Kerr-McGee Oil (U.K.) plc 8%, British Gas Exploration & Production Ltd. 7.7%, LL&E (U.K.) Inc. 6.3%, Sovereign Oil & Gas plc 4%, and British-Borneo Oil & Gas Ltd. 2%.

DANISH OPERATIONS

WoodMac said development off Denmark is driven by expansion of producing fields, while a new wave of fields is expected on stream during the mid to late 1990s.

Meantime, exploration off Denmark will decline sharply during the next 2 years, largely because no new licensing rounds are scheduled. Industry drilled 10 wildcats in the Danish North Sea during 1992, but no new discoveries were disclosed.

Capital spending in the Danish North Sea is expected to peak in 1994 at 4.9 billion Danish kroner ($800 million) billion) and remain at more than 2 billion kroner ($300 million)/year until the end of the 1990s.

WoodMac said things such as horizontal drilling and large scale waterflood projects are boosting recovery rates off Denmark.

Maersk Olie & Gas AS almost doubled expected recovery in Dan oil field to about 15% under its current development plan from 8% under initial development phases. Two new platforms will be bridge-linked to existing structures, while drilling of I) development wells is planned.

Dan production is to increase to 64,000 b/d in 1994 from the 1991 average of 30,000 b/d.

Maersk also plans as many as 20 development wells and full scale waterflooding in Gorm field. A new deck will boost Gorm capacity. A peak of 36,000 b/d of oil is expected in the mid-1990s, compared with an average 26,000 b/d in 1991.

Maersk last August submitted plans for expansion of Skjold field, involving drilling of 10 development wells and installation of two more platforms. That would maintain production at about 40,000 b/d into the mid-1990s.

In October, Maersk submitted a plan to expand its Tyra field development. This involves installation of three platforms bridge-linked to East Tyra facilities and drilling of 18 horizontal production wells, half for oil and half for gas. Liquids production could thus be jacked up to 30,000 b/d during the next few years from the 1991 level of 24,000 b/d.

NEW DEVELOPMENT

Valdemar and Regnar oil fields, also operated by Maersk, are expected to go on stream in late 1993 or early 1994, although the development plan awaits approval.

Maersk intends to develop Valdemar using a multiphase spur line to Tyra field. Two other reservoirs, Svend and Harald, are expected to be tied back to Tyra in 1995 and 1997, respectively.

Regnar will be the first Danish subsea development, a single wellhead tied back to Dan and due on stream late this year.

WoodMac foresees another wave of development project towards the end of the century. Adda, Igor, Elly, and Gert fields are expected to be tied back to existing infrastructure about the end of the decade.

Combined oil and NGL production from fields under current and probable development projects off Denmark is expected to reach almost 50,000 b/d by the turn of the century. The country produces 164,000 b/d of crude oil at present.

DANISH RESERVES

WoodMac cited increases in Danish reserves and production in recent years, mostly through field expansion programs.

It said estimated recoverable reserves rose to the present 2.1 billion bbl of oil equivalent (BOE) from 1.6 billion BOE in 1989 .

WoodMac figures show oil and NGL production during the same period climbed to an average 155,000 b/d from 110,000 b/d, while gas flow rose to 390 MMcfd from 274 MMcfd.

Liquids production is expected to peak at 200,000 b/d in 1994 and remain near that level to the end of the decade, while gas production will reach 650 MMcfd at the end of the decade.

The crude oil pipeline from Gorm field to Fredericia on the Jutland coast, which serves all Danish fields, is expected to reach capacity before the end of 1994. Two options are foreseen: an offshore pump station could be installed to raise pipeline capacity to 230,000 b/d or a 50,000 b/d loading system on the Gorm platform could be reactivated. The system has been idle since the early 1980s.