ABSTRACT: Hunting Oil Between Elephants in Block 34/7 on the Norwegian Shelf

Arvid Elvsborg, Stein Nybakken, Terje Solli

Block 34/7 is located east of the Statfjord field, producing since 1979, and north of Gullfaks field, producing since 1986. Snorre field in the block should begin production in 1992. These three fields have more than 11 billion bbl in place and 5 billion bbl recoverable reserves.

A heavy exploration program is done parallel to field development studies. The exploration activity is due to approaching relinquishment and securing tie-in to existing infrastructure. Because of extensive production facilities, small reserves can be used and all traps are now mapped and risk evaluated.

So far, four discoveries have been made outside the Snorre field: Statfjord Ost, Snorre Vest, C, and B. Estimated recoverable reserves are 400 million bbl. However, additional prospects could more than double these reserves.

Exploration started with conventional structural traps. The two latest discoveries are pinch-out traps, and the next to be tested by wells are sealing fault traps.

The East Flank is a separate province downfaulted 2 km with several structures depending on sealing faults. New stratigraphy will be tested by the next well, which is deviated to penetrate possible Lower Cretaceous and Upper Jurassic reservoir before reaching the main goal, which is the Brent reservoir. The results of this well could be very important for the opening of possible new play concepts in the northern North Sea.

A sealing fault trap with Brent reservoir on the Tampen Spur will be tested by a well in 1990. Exploration is, however, in progress at several other stratigraphic levels within Tertiary, Upper and Lower Cretaceous, and other Upper Jurassic reservoirs where the possibilities for stratigraphic traps exist. These will tested during next year's exploration program to secure potential reserves for field development at low production cost. Today, the minimum economic recoverable reserves in a prospect are 5-10 million bbl. However, it is expected that this volume could be significantly reduced during the production history of this area, which will probably last beyond 2020.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990