Concrete oil production platforms appear ready to make a comeback in the U.K. North Sea.
Amerada Hess Ltd. favors a concrete substructure for Scott field, the largest oil reservoir currently under development off the U.K.
At the same time, McAlpine Offshore and Doris Engineering have formed a joint venture to undertake complete design, construction, and installation for concrete structures in the British North Sea.
In other North Sea action:
- Conoco (U.K.) Ltd. started initial development studies for Buckland oil field in U.K. Block 9/18a after testing the latest appraisal well.
- A Marathon Oil U.K. Ltd. group was evaluating results of the 16/3a-11 discovery well in the Brae field area but on a separate structure.
- Off Norway, Elf Norge improved prospects for developing Froy field in Block 25/2 with the successful appraisal on a nearby structure that would be developed as a satellite of the main field.
- Norske Shell gauged an oil and gas discovery near Dansk Undergrunds Consortium's Harald oil and gas field, which lies off Denmark.
CONCRETE DESIGN
Amerada Hess awarded the Scott field engineering design contract to Foster Wheeler Petroleum Development & Associates Ltd.
The operator said the final development concept is likely to be based on a concrete substructure with separate processing and accommodation arrangements.
The 400 million bbl field is scheduled to start production at the end of 1993. Pipeline options for the field are still under consideration.
Partners in the field are Amerada, Amoco (U.K.) Exploration Co., Deminex U.K. Oil & Gas Ltd., Enterprise Oil plc, Kerr-McGee Oil (U.K.) plc, Mobil North Sea Ltd., Pict Petroleum plc, and North Sea Inc.
The two partners in the McAlpine-Doris joint venture have considerable experience in concrete construction.
McAlpine Offshore has been working on new platform designs and removal of gravity platforms. Its parent company, Sir Robert McAlpine & Sons Ltd., in association with Sea Tank Co. built three concrete platforms at Ardyne Point, Scotland, for the first generation of U.K. and Norwegian fields.
Sea Tank merged with Doris Engineering in 1981. Doris was responsible for design and installation of nine concrete gravity platforms in the North Sea and recently carried out the conceptual and front end engineering for the Ekofisk protective barrier.
BUCKLAND FIELD
Conoco named its Block 9/18 field Buckland after testing 5,452 b/d of 38 gravity Jurassic oil at the 9/18a-18 appraisal well, drilled to 12,900 ft.
The small structure is 150 miles northeast of Aberdeen, near Mobil North Sea's Beryl field.
Conoco also found oil about 51/2 miles south of the Buckland appraisal well with its 9/18a-21 wildcat, which flowed 4,030 b/d of 21.9 gravity crude from Eocene. Total depth is 6,500 ft.
Further exploratory drilling is planned on Block 9/18a and adjoining Conoco-operated Block 9/19 later this year.
Ownership of Block 9/18a differs according to the subsea depth. Above 9,500 ft, Conoco, BP Exploration, and Chevron U.K. Ltd. each hold a one-third interest.
Below that depth, within the block subarea in which Buckland is located, Conoco holds 39.83%, BP 26.83%, and Chevron 33.33%.
The Marathon group's Brae area discovery well flowed 2,016 b/d of oil through a 3/4 in. choke. The Western Pacesetter IV semisubmersible spudded the well last October.
Brae group partners are Marathon 38%, Britoil plc 20%, Bow Valley Petroleum (U.K.) Ltd. 14%, Kerr-McGee Oil (U.K.) plc 8%, Gas Council (Exploration) Ltd. 7.7%, LL&E (U.K.) Inc. 6.3%, Sovereign Oil & Gas plc 4%, and Norsk Hydro Oil & Gas Ltd. 2%.
FROY SATELLITE
Elf Norge tested oil and gas from four zones in its 25/2-13 appraisal well, north of the Froy structure in the Frigg/Heimdal area of the Norwegian sector.
The best gauge was 4,297 b/d of oil and about 768 Mcfd of gas. Reserve estimates are in the lower part of the 30-60 million bbl range Elf expected before drilling the well.
Elf has spudded the 25/5-3 wildcat on a structure located south of Froy.
The company is still working on development options for the main Froy structure, which has reserves of 95-125 million bbl.
Provision is being made to include at least one satellite field.
Norske Shell's 3/7-4 wildcat flowed 3,900 b/d of 46.3 gravity crude oil and 29.4 MMcfd of natural gas through a 19 mm choke. Reserves are thought to be 300-400 bcf of gas and 40-50 million bbl of oil.
The well is the first discovery in the Norwegian sector from the Sojne basin, which contains Harald field structures in Danish waters.
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