The Jurassic Snehvit Gas Field, Hammerfest Basin, Offshore Northern Norway
The first well offshore northern Norway was drilled in 1980, and the Snøhvit field, which is the largest gas find and the first oil discovery in the area, was discovered in 1984. The Snøhvit field is in the southwest Barents Sea in the center of the Hammerfest Basin and straddles blocks 7120/6, 7121/4, and 7121/5. Water depth is approximately 300 m. The field covers 90 km2 (22,200 ac) and has a gas column of 124 m (407 ft) overlying a 14 m (46 ft) thick oil leg. This oil leg makes Snøhvit the only significant oil find on 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 a separate fault block, define the Snøhvit field. The wells have common fluid contacts. Reservoir properties are fair, with a porosity of 15% and permeability from 200 to 500 md in the main reservoir. The water saturation in the gas zone averages 10%, and varies from 3 to 26%.
A burial history involving uplift, erosion, and renewed burial during the Tertiary has influenced the distributions of oil and gas in the reservoir and the positions of the fluid contacts.
The most likely estimate of gas in place is 160 billion standard m3 (5.6 tcf), and the gas has a recovery factor of 70%. The oil in place is estimated at 73 million standard m3 (450 million bbl). Because of 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 Snøhvit gas, but currently there are no firm development plans.
Figures & Tables
The success of Memoir 14 and the worldwide interest shown for data on giant fields prompted AAPG to schedule a symposium on giant fields at the end of each subsequent decade. The 1968-78 symposium was held in Houston, Texas, April 1-4, 1979, and the papers were published in AAPG Memoir 30, December 1980.
The Stavanger Conference "Giant Oil and Gas Fields of the Decade: 1978-1988" was held in Stavanger, Norway, September 9-12, 1990, and is a continuation of the Giants of the Decade series.
Scientific studies and projections of future world energy demand indicate that although alternative-energy fuel sources must be actively pursued and developed, there also must be adequate petroleum supplies to bridge the gap. For the international petroleum industry, the years covered by this conference, 1978-88, were complex. They were years of boom and bust. The world's energy consciousness was boosted sharply by the effects of the 1979 Iranian revolution and the resulting embargo, which sent world oil prices to record heights. Global petroleum exploration soon surged, leading to the industry's all-time drilling high in 1981. Then came the oil price collapse in 1985, and the following years were characterized by falling oil prices and drastic budget cuts for exploration and development.
Although exploration dropped sharply during the latter part of the decade, there was a steady flow of giant oil and gas field discoveries. Using the giant field designation criteria of 500 million bbl of oil recoverable for fields in Asiatic Russia, North Africa, and the Middle East,