The first two platforms built to Amoco's minimum offshore supporting structure (Amoss) blueprint were completed early this month. They were to be towed out to the fields in mid-March.
Also off Northwest Europe:
- Norsk Hydro AS let a 2.8 billion kroner ($430 million) contract to Aker AS, Oslo, for engineering, construction, and outfitting of a floating production platform for development of Njord field in the Norwegian Sea off Norway
- Norway's oil and gas authorities are growing excited over a Norwegian Sea gas discovery by Saga Petroleum AS, claiming it may be as big as any gas strike off mid-Norway.
- Companies awaiting results of a feasibility study for development of Smoerbukk, South Smoerbukk, and Midgard fields in the Norwegian Sea have agreed on unitization of the planned 40 billion kroner ($6.1 billion) development.
- Norwegian oil production is expected to increase significantly during the second half of the year to reach an average 3.3 million b/d in December. That is the prediction of Wood Mackenzie Consultants Ltd., Edinburgh, which says Norway's average production for all of 1995 will average 2.98 million b/d.
DAVY, BESSEMER
Amoco's Block 49/30a Davy and Block 49/23e Bessemer structures are minimum facilities platforms scheduled to be tied back to the company's Indefatigable complex on Block 49/23a. Amoss represents the first use of a monotower platform off the U.K. (OGJ, Jan. 9, p. 14). The design could be used for development of other marginal fields in the region.
Don Nelsen, Amoco projects manager, said the design's single leg makes it easy to employ in different water depths, but the key to its success is likely to be the minimum facilities of its topsides.
"Early North Sea platforms were overdesigns," Nelsen said. "For Amoss we included in the topsides only what will be needed to keep production on stream. Compared with a design for a similar project 10 years ago, the Amoss platform is one third the weight."
Davy and Bessemer platforms each weigh about 1,050 metric tons, of which 400 metric tons is topsides. They will be towed to the fields on a single barge and installed late this month by the M7000 crane barge operated by Saipem U.K. Ltd., Aberdeen.
Davy and Bessemer are the world's first oil and gas platforms to use wind turbines to generate operational power requirements. These reduce the need for regular service trips because one of the main reasons for such trips is refueling platform generating sets.
Malcolm Dorricot, managing director of Brown & Root McDermott Fabricators Ltd., which built Davy and Bessemer platforms at its Nigg yard in Scotland, said Mobil North Sea Ltd. has ordered a similar platform to develop its Galahad gas prospect in the southern North Sea.
Work on the Galahad structure will start soon at Nigg. Dorricot said the fabricator and Amoco want to build Amoss platforms in groups, with only slight changes from platform to platform.
Nelsen said if four Amoss platforms were built at the same time, cost reductions from economies of scale would effectively provide the fourth platform free.
Combined development cost for Davy and Bessemer, which is expected to be reduced per platform for later projects, is estimated at 84 million ($126 million).
Sarah Delaney, Amoco's southern basin resources manager, said Amoco has earmarked Amoss for use on three prospects in the Indefatigable field area, which are to be drilled this year.
North Indefatigable, West Davy, and Bell prospects have been identified from 3D seismic data Amoco has acquired all around its southern North Sea installations.
Delaney said if gas were found in these prospects, the first could be on production next year. Amoco has identified at least six prospects in the area.
Experience with Davy and Bessemer, expected to require 18 months for development, was said to have shown that development times can be reduced further.
"We want to make a cookie cutter design," Delaney said. "Prefabricated components will keep down development time, as will predrilling of production wells through templates."
Nelsen said Amoco will shortly begin work on a second version of the Amoss design that will offer an "off-the-shelf" platform and reduce field development time to about 1 year.
Amoco is talking to other operators about use of Amoss on their fields.
The company expects Davy and Bessemer platforms to be reusable after their 7-8 year field life.
NJORD PLATFORM
Aker's Njord platform contract bid was based on use of its P45 concept, an adaptation of its H3 semisubmersible drilling rig design. Njord marks the first use of this design for field development. The basic design is for a unit with capacity to produce 65,000 b/d of oil and 10 million cu m/day of gas. Block 6407/7 Njord field holds estimated reserves of 220 million bbl of oil and 5 billion cu m of gas.
Work on Norsk Hydro's Njord platform will begin at once, with tow out slated for June 1997.
"We chose a simple, standardized design with a short construction time and considerable flexibility and reuse value," said Aker Pres. Tom Ruud. "As required, the platform can be easily extended and modified."
Aker's P45 concept consists of a twin pontoon hull with four columns and a truss structure carrying a flat deck on which are mounted production modules. Aker claims the concept works out 40% cheaper than a conventional production semisubmersible.
SAGA DISCOVERY
Saga's Block 6406/2 wildcat reportedly found gas and condensate in four Jurassic zones. The well was drilling ahead at last report, with the Ross Rig semisubmersible rig operating in 280 m of water.
A Saga official said the well was at 5,290 m total depth and had a number of days drilling to go. Planned total depth is 5,000 m, and this had been extended twice because pay zones were deeper than expected.
A Norwegian Petroleum Directorate official said the strike could equal the size of Smoerbukk and Midgard gas fields, currently under study for development by Den norske stats oljeselskap AS.
The NPD official said the discovery well was not tested and because of limitations on drilling during the fish spawning season of spring, it is not likely to be tested until summer.
The Saga official said it is too early to say how large the find is, but it is "big stuff, probably one of the largest finds in the Norwegian Sea."
An extended well test will be run during the summer, and an appraisal well will be required before a number can be placed on reserves.
Smoerbukk holds estimated reserves of 95 billion cu m of gas and 37 million cu m of condensate. Midgard reserves are estimated at 103 billion cu m of gas, 15. 5 million metric tons of condensate, and 1.4 million cu m of oil.
SMOERBUKK/MIDGARD
Statoil reported the eight licensees involved in Smoerbukk, South Smoerbukk, and Midgard fields have agreed on an equal split of assets in all three fields. Statoil said negotiations required only 2 months even though they were among the most complex off Norway to date.
Equal partners in the three field project are: operator Statoil, Saga, Mobil Development Norway AS, Neste Petroleum AS, Norsk Agip AS, Total Norge AS, Norsk Hydro AS, and Enterprise Oil Norge AS.
Results of the feasibility study are to be submitted to operator Statoil by the end of March. Fixed and floating structures and a combination of the two are among development plans under study (OGJ, Jan. 23, p. 17).
NORTH SEA OIL PRODUCTION
The expected increase in Norway's offshore oil production will come from new fields entering production. Heidrun, West Troll, North Statfjord, Froey, and Yme fields, all due on stream this year, are expected to produce more than 500,000 b/d in total at peak.
Danish and Dutch offshore oil production is expected to fall this year, by 4% and 8% respectively. No new fields are expected on stream in either sector this year, although redevelopment work continues off Denmark.
Wood Mackenzie said Norwegian oil flow averaged 2.8 million b/d during January, down from the record 2.96 million b/d averaged in December. The fall stemmed from maintenance work in Draugen field and rough weather that interrupted offshore loading.
Total U.K. oil production averaged 2.6 million b /d in January, down about 100,000 b/d from December. Again, this was due to storms interrupting offshore loading in some fields.
U.K.'s two newest offshore fields, Dunbar and Ellen operated by Total Oil Marine plc, have doubled production since start-up in December. Dunbar averaged 20,000 b/d in January and its Ellen satellite 3,000 b/d.
Oil production off Denmark rose 1,000 b/d to average 185,000 b/d in January Record flow from Dan field more than offset declining production from Skjold and Kraka fields.
Dutch oil production fell 2,000 b/d to average 55,000 b/d during January. This was partly caused by declining flow from Horizon field, where operator Unocal Netherlands BV is expected to drill two wells this year to shore up production.
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