Norsk Hydro has started a 12 month production test of extensive oil reserves underlying Troll gas field in the Norwegian North Sea.
The company is using the Petrojarl test ship to produce a single horizontal well drilled into a 72 ft thick oil zone under the western lobe of the giant gas field. The well, in 1,085 ft of water, is producing about 12,000 b/d.
If the year-long test is successful, Norsk Hydro could have a floating oil production system operational in West Troll by 1994, 2 years before planned start-up of gas production from East Troll in 1996.
Meantime, Conoco Norway Inc. submitted to the Ministry of Petroleum and Energy an updated development plan for Heidrun oil and gas field in the Haltenbanken area.
TROLL TEST
The Norwegian Petroleum Directorate reports there are 260 million bbl of recoverable crude in the thin zone being tested by Norsk Hydro.
A second zone 33-50 ft thick holds 2.5 billion bbl of oil in place. Norsk Hydro plans a production test of the second zone, also using the Petrojarl.
The current well has a 1,640 ft horizontal section. Production through Petrojarl is expected to rise to a peak of 30,000 b/d.
The company is working on several development options.
Norsk Hydro owns a 7.688% interest in Troll. Its largest interest partner is Den norkse stats oijeselskap AS with 74.576%.
HEIDRUN DEVELOPMENT
Conoco's 19 billion kroner ($2.93 billion) Heidrun development project calls for a concrete tension leg platform with a production capacity of 200,000 b/d. It is to be operational by 1995.
Key to government approval for the project is a means to use Heidrun's 1-1.5 tcf of gas reserves. Conoco favors an 840,000 ton/year onshore methanol plant to handle the gas, although gas could be reinjected for a short time.
Current schedule for the 750 million bbl oil development plans calls for a start of preliminary engineering in the third quarter of this year, detailed engineering in July 1991, and topsides construction in November 1992. The concrete hull would be mated to the topsides in October 1994.
The unit would be installed over nine predrilled wells - seven producers and two gas and water injection wells-in summer 1995 with production starting shortly after that. The development drilling program calls for 49 wells-35 producers, 11 water injectors, and 3 gas injectors.
The concrete TLP will be able to inject as much as 330,000 b/d of water and 145 MMcfd of gas.
Oil will be tanker loaded.
Conoco, with a 35.65% interest in the field, will be operator for the development phase. Statoil, its biggest partner with a 50.75% interest, will operate the production phase.
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