Role of Geology in Developing the Argyll Field

Ronald Bifani

The Argyll field was discovered in 1971, brought on stream in 1975, and has the distinction of being the first oil-producing field in the United Kingdom's North Sea area. Development drilling has proved commercial oil from five reservoir zones in rocks ranging in age from Devonian to Late Jurassic. The geology for each zone varies in lithology, depositional environments, and reservoir characteristics. Structure is complex and affects production, reservoir pressure, and communication between producing zones.

The Zechstein dolomites are unique reservoir rocks in the U.K. North Sea in that they are productive only in the Auk and Argyll fields. The key to their excellent reservoir characteristics can be attributed to postdepositional tectonic uplift and karst leaching.

The Rotliegendes Sandstones represent an interval of continental deposits. The prolific eolian reservoir sands exhibit good porosities and permeabilities, but are limited to the central part of the field. The underlying fluvial deposits exhibit poorer porosity and permeability characteristics, facies distribution is more varied, and reservoir prediction is more problematic due to rapid changes in sedimentation. New drilling in the field has revived interest in the Rotliegendes, and a new episode of development is beginning.

This presentation highlights the geology of each reservoir zone in the Argyll field and the importance of geology in reservoir development planning.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.