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ABSTRACT: Snohvit--a Sleeping Beauty

Randi Grung Olsen, Arne Linjordet

The first well offshore northern Norway was drilled in 1980. The Snohvit field, which is the largest gas find in the area, was discovered in 1984. The field is located on Tromsoflaket in the central part of the Hammerfest basin and straddles Blocks 7120/6, 7212/4, and 7121/5. Water depth is 300 m. The field covers an area of 80 km and has a gas column of 105 m overlying a 14-m-thick oil leg. This oil leg makes Snohvit the only significant oil find in the Barents Shelf to date.

The reservoir consists of Lower to Middle Jurassic sandstones deposited in a transgressive coastal to inner shelf sequence. Three wells, each situated in different fault blocks, define the Snohvit field. The wells have common fluid contacts. Reservoir properties are fair with a porosity of 16% and a permeability ranging from 200 to 500 md in the main part of the reservoir. The water saturation in the gas zone is low, varying from 5 to 15%.

A burial history with uplift and erosion and renewed burial in the Tertiary appears to have influenced the position of the fluid contacts and the distribution of oil and gas in the reservoir.

The gas in place is estimated at 142 G Sm3 with a recovery factor of 0.7. The oil in place is estimated at 68 M Sm3. Due to the thin oil leg and the areal distribution of the oil in the reservoir, it is not thought economically feasible to develop the oil with present-day technology.

Various development scenarios have been studied for the Snohvit gas, but currently there are no firm development plans.

AAPG Search and Discovery Article #91000©1990 AAPG Conference-Giant Oil and Gas Fields of the Decade 1978-1988 Conference, Stavanger, Norway, September 9-12, 1990