ABSTRACT: The Alba Field--a Middle Eocene Deepwater Channel in the UK North Sea

George A. Mattingly, Henry H. Bretthauser

The Alba field is located in the Witch Ground Graben between the Fladen Ground Spur to the north and the Renee Ridge to the south, entirely in UKCS in Block 16/26. In 1985, oil was discovered in the middle Eocene sandstones of the Horda Formation at a depth of 6100 ft subsea. Twelve additional wells, including sidetracks, have been drilled to appraise the discovery. This drilling indicates the Alba field is a stratigraphic trap covering an area of 3400 ac.

The Alba sands represent a brief interruption in the hemipelagic sedimentation that dominated this part of the Witch Ground Graben during the middle Eocene. Sediment was supplied intermittently from a shelf to the northwest into a deep-water environment. Well correlations, seismic facies analysis, and core analysis indicate that these sands were deposited as part of a constructional channel/levee complex within a mud-rich, shelf-sourced submarine fan system. The cap, updip, and lateral seals to the reservoir are shale.

The Alba reservoir is predominantly a homogeneous, fine-grained, unconsolidated sandstone. The average reservoir porosity is 33% and the average permeability is 2.8 d. Oil in place is estimated to be 1.1 billion bbl of 20° API crude.

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