U.K. operators start up three oil fields

U.K. offshore operators continue to exploit small discoveries near maturing giants.

Three new oil field developments were brought on stream in as many days last month:

On Aug. 9, Amerada Hess Ltd. began production from Block 21/11 Dauntless field, and 2 days later started up Block 21/16 Durward, developed jointly with a production, storage, and offloading ship (FPSO).
On Aug. 10, Conoco (U.K.) Ltd. began oil production from MacCulloch field on Block 15/24 with an FPSO.
The following day, Mobil North Sea Ltd. disclosed first production from Katrine field on Block 9/13a, under an extended well test. Production was achieved by completion of an appraisal well drilled from nearby Nevis field facilities.

Elsewhere off the U.K., Enterprise Oil plc, London, has won U.K. Department of Trade and Industry (DTI) approval of its development plan for Pierce oil field in the central North Sea.

On Block 22/11 Nelson field, operator Enterprise has been preparing to remove a World War II bomb discovered last month only 3 m from the field's oil export pipeline.

Also, Britannia Operator Ltd. (BOL) and Elf Exploration U.K. plc have installed platform jackets in Block 16/26 Britannia field and in Block 22/30c Elgin and Block 29/5b Franklin fields, respectively.

Durward/Dauntless

Durward and Dauntless lie 7 km apart and were developed with subsea production units tied back to the production ship, which is moored between the two fields.

Durward was started up with two production wells and a water injector. The need for additional wells will be determined as production progresses. Dauntless was developed with one production well and a water injector.

Combined initial production is 25,000 b/d. Estimated reserves for Durward and Dauntless fields are 30 million bbl and 13 million bbl of oil, respectively.

The Glas Dowr production ship is owned and operated by Bluewater Offshore Production Systems Ltd., Essen, Belgium. The ship is a newbuild tanker converted for production duty.

Glas Dowr has capacity to handle 75,000 b/d of liquids and produce as much as 60,000 b/d of oil. It can store 657,000 bbl of crude oil and discharge to a shuttle tanker at rates of as much as 25,000 bbl/hr.

The ship also has capacity to handle 65,000 b/d of produced water and produce as much as 24.5 MMcfd of associated gas. Produced gas is used to fuel onboard generators, with an excess being flared. Gas lift facilities may be installed later.

Durward/Dauntless field partners are operator Amerada 28%, Saga Petroleum (U.K.) Ltd. 23.5%, DSM Energy (U.K.) Ltd. 20%, British-Borneo Petroleum Syndicate plc 18.5%, and Seafield Resources plc 10%.

MacCulloch

Conoco's MacCulloch field has estimated reserves of 58 million bbl of oil. Production is expected to peak at 60,000 b/d of oil and 12 MMcfd of associated gas.

Oil from MacCulloch is metered on the ship and transported by pipeline to Piper B platform, 30 km northwest, operated by Elf. Associated gas also is exported to Piper B by pipeline.

The field's production ship, North Sea Producer, is a converted products tanker, formerly named Dagmar Maersk. It has capacity to store 560,000 bbl of oil if the export pipeline is unavailable.

The ship is owned and operated by North Sea Production Co., a joint venture of Odebrecht-SLP Engineering Ltd., Lowestoft, U.K., and Maersk Oil & Gas AS.

MacCulloch is initially producing through three wells tied back to the ship by flexible flow lines and risers. Further production wells are expected to be drilled later this year.

MacCulloch field interest holders are operator Conoco 60% and Lasmo North Sea plc 40%. The ship is leased to Conoco under a per-barrel tariff arrangement.

Katrine

Mobil's Katrine field was put into production by completing the 9/13a-S59X appraisal well, which was drilled through the subsea manifold in Nevis field, itself a subsea satellite of Mobil's Beryl Alpha platform.

Initial production from Katrine is 8,000 b/d of oil and 4 MMcfd of gas. Oil is piped to Beryl A for processing and exported by shuttle tanker. Gas is sent to Beryl to join the Scottish Area Gas Evacuation pipeline to St. Fergus, Scotland.

Mobil said DTI has consented to a 6- month extended well test in Katrine, which will enable the company to evaluate options for further development.

Katrine reserves are believed to be estimated at 23 million bbl of oil and 12 bcf of gas. Any development is expected to be a subsea satellite tie-back to Beryl Alpha, similar to Nevis.

Interest holders in Katrine are operator Mobil 50%, Amerada 22.222%, Enterprise 22.778%, and OMV (U.K.) Ltd. 5%.

Pierce approval

In addition to securing approval to develop Pierce field, Enterprise also completed its deal with BP Exploration Ltd., calling for the London independent to increase its interest in the field to 74%.

DTI approved the Pierce development plan Aug. 22. First oil is slated for August 1998 at 20,000 b/d, with a plateau of 45,000 b/d expected soon thereafter.

The field lies on Blocks 23/22a and 23/27 in the central North Sea, 280 km east of Aberdeen. Proven plus probable reserves are estimated at 84 million bbl of oil and 202 bcf of gas.

Development plans call for leasing an FPSO with oil exported via shuttle tankers and produced gas to be reinjected. Six oil producers and three gas injectors will be drilled by a Diamond Offshore Drilling (UK) Ltd. semisubmersible.

Enterprise earlier let contracts to Norway's Statoil AS to furnish the FPSO and shuttle tankers. These contracts allow for a field life of 5-13 years from first oil.

Enterprise also let contracts to Coflexip Stena Offshore Ltd. for supply of flexible flow lines and risers, Rockwater Ltd. for subsea manifolds controls and installation, and Wells Development Alliance for integrated well services.

With completion of the deal with BP, Enterprise has acquired all of BP's 42.8% interest in Pierce in exchange for its 24.05% interest in Amethyst field and 13.5% interest in Ravenspurn North field.

Partners in Pierce with operator Enterprise Oil 42.8% are Enterprise Oil Exploration 31.2%, Ranger Oil (UK) Ltd. 15.6%, MOC Exploration 3.75%, Agip (UK) Ltd. 3.73%, and Santos Europe Ltd. 2.93%

Capital costs are pegged at £150 million during 5 years, and the lease of FPSO and ancillary facilities is expected to cost about £100 million during 5 years.

The field was discovered with the 23/27-3 well in 1975.

Nelson bomb

Enterprise's discovery of the unexploded bomb near the Nelson oil export pipeline came during a routine survey of the line in mid-July.

The bomb is 1.15 m long and estimated to weigh 250 kg.

Noting that it had not been spotted during previous surveys, Enterprise believes the bomb was snagged by a fishing boat's trawl net and moved close to the pipeline.

The operator has called in Royal Navy and Ministry of Defense experts to advise contractors on removing the bomb with a remotely operated vehicle. The operation was due to take place by Aug. 25.

Nelson production will be halted for 3-5 days while the bomb is removed. The 25 km, 20-in. export line, which runs from Nelson to the Forties system Unity riser platform, will be flooded with water during the removal.

Nelson production has recently averaged 150,000 b/d. Production in Forties field and others linked to the Forties export system will not be affected, said Enterprise.

Jackets

BOL is a joint venture of Chevron U.K. Ltd. and Conoco, set up to operate Britannia field jointly.

The field is U.K.'s largest undeveloped gas/condensate find.

Britannia is due on stream in November 1998 and is expected to reach peak production of 550 MMcfd of gas and 45,000 b/d of condensate. Britannia reserves are estimated at 3 tcf of gas and 165 million bbl of condensate.

Kvaerner John Brown Ltd., London, designed the Britannia jacket, which was built in Spain by Dragados y Construcciones SA, Madrid, and installed by Heeremac VOF of Leiden, Netherlands.

The jacket weighs 20,700 metric tons and was installed in 136 m of water. A 29,000-ton modular topsides will be installed on the jacket late in August.

Elf's Elgin and Franklin wellhead platform jackets were built by Lewis Offshore Ltd., Stornoway, U.K., and installed using the S7000 crane barge in mid-August by Saipem U.K. Ltd., Aberdeen.

Each of the jackets weighs 3,000 metric tons and stands in 93 m of water. A production, utilities, and quarters platform will also be installed in Elgin. First production is slated for 2000. Elgin/Franklin reserves are estimated at 1.25 tcf of gas and 200 million bbl of condensate.