Andrew J. Pulham1,
(1) University of Colorado, Boulder, CO
(2) University of Alberta, Edmonton, AB
(3) BP Amoco Exploration, Aberdeen, Scotland
(4) BP Amoco Exploration, AK
(5) BP Amoco Exploration Research, Sunbury, England
(6) Biostrat, Cumbria, England
Abstract: Reservoir stratigraphy and reservoir performance in the Bruce Field, Middle Jurassic, Northern North Sea: Anatomy of a transgression in a rift embayment
The Bruce Field is a large gas and condensate field in the Northern North Sea. Bruce reservoirs were deposited during the late transgression of the Middle Jurassic Brent Delta and therefore postdate the major accumulation of thick fluvio-deltaics that comprise the classic Brent-type reservoirs.
Producing sandstones comprise a thick section of syn-rift, lower delta plain, nearshore and restricted marine environments that were deposited during a regional north to south transgression of the Viking Graben. The nature of this transgression in the Bruce area has been described and interpreted through the use of quantitative biostratigraphy and ichnofacies analysis combined with sedimentological and petrographic studies and the use of dynamic data such as RFT pressures and PLT production logs. The architecture of the Bruce reservoirs and particularly their reservoir quality can be linked directly to the nature of the regional transgression. Of particular importance are changes in sediment supply that occur through time and the interplay between contemporaneous faulting and the paleogeography of the local rift basin. The most important stratigraphic event is a key marine flood that resulted in the deposition of a laterally extensive and high permeability sandstone across large parts of the field area. The second most important event is related to an interpreted period of tidal amplification in the rift basin that resulted in the incision of deep tidal channels containing high quality reservoir facies.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana