ABSTRACT: The Snorre Field--a Major Field in the Northern North Sea

Knut Jorde, Geir W. Diesen

The Snorre field is located in the northern North Sea and belongs to the prolific hydrocarbon province on the western margin of the Viking Graben that contains fields such as the Brent, Statfjord, and Gullfaks fields. The Snorre field was discovered in 1979 and has two main reservoirs, the Triassic Lunde and the Triassic to Jurassic Statfjord Formation, both consisting of a network of fluvial sandstones in a mudstone matrix.

The reservoir properties range from fair to very good, with typical test permeabilities of 2000 md in the upper part of the Statfjord, and 125-380 md in the underlying units.

The field contains 490 million Sm³ (3 billion bbl) of undersaturated oil, of which approximately 75% occurs in the Lunde Formation. The oilwater contact varies somewhat over the field, from 2561 m (8400 ft) on the crest to 2599 m (8530 ft) in the western part.

The field is a structural-stratigraphic trap formed by the westward tilting and erosion of a major fault block. Both reservoirs are truncated by the Kimmerian unconformity and overlain by Jurassic and Cretaceous shales. Organic-rich Upper Jurassic shales constitute the major source rock.

The field will be subject to a phased development, with a tension-leg platform (TLP) that initially will be located in the southwestern part of the field. Production will start in 1992 by using six wells pre-drilled from a template beneath the TLP. Additional TLP wells and another subsea

template will complete phase 1 of the development.

Phase 2 has two different options: (1) relocating the TLP to the northern part of the field or (2) leaving the TLP it in its original position and adding two more subsea templates.

The field development plan uses water injection, and includes 75% of the oil in place. Based on this, 119-122 million Sm³ (750-790 million bbl) of oil is estimated to be recovered for the extended subsea and relocation alternative, respectively. Studies are presently being done to increase field production by developing parts of the reservoir that are not included in the current plan.

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