Norsk Hydro AS again has increased estimated reserves of Troll field in the Norwegian North Sea and released more details about a third platform there.
In a press conference at the Offshore Northern Seas meeting in Stavanger, Hydro officials said the company now reckons Troll holds about 1.2 billion bbl of oil, including 450 million bbl in the field's oil province and the rest in a thin oil layer within its gas prone area.
Hydro earlier had doubled Troll's estimated reserves to about 1 billion bbl (OGJ, Aug. 26, p. 28).
Troll platform
Troll West operator Hydro said Troll C semisubmersible platform will be installed in the northeastern part of the field's central gas province.
Thor Tangen, vice-president for the Troll project, said the platform will be designed to produce as much as 125,000 b/d of oil and 320 MMcfd of gas.
Development plans call for drilling as many as 56 horizontal wells that are to be tied back by way of subsea manifolds, half to Troll B and half to Troll C. The Polar Pioneer semisubmersible rig is to begin drilling the wells in October 1997.
Officials estimate total cost of Troll C platform and the 56 horizontal wells at $2.2-2.3 billion, boosting Troll's total development cost to $4.5 billion.
Troll details
Hydro expects to let a contract December 1996 for construction of Troll C platform.
Three contractors have prequalified to bid: Aker AS and Kvaerner AS, both of Oslo, and Umoe Haugesund AS, Haugesund, Norway.
Bjoern Sund, Hydro's senior vice-president of field development and technology, said Troll West is producing oil from 12 wells in the oil province and 2 in the gas zone.
Most are performing better than expected, with less water cuts and no gas breakthrough.
Tangen said gas will be exported from Troll C through a new pipeline to shore.
Gas is to be moved via pipeline 29 km to Troll A gas platform, a concrete gravity-base facility to be installed next October in Troll East field by Norsk Shell AS.
Hydro late this year plans to drill Troll's first dual lateral well to help set further development plans.
Troll production began September 1995 through Troll B semisubmersible platform, now producing at full capacity of 250,000 b/d of oil.
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