Andrew J. Pulham1,
T. Saunders2,
S.G Pemberton2,
D. Ewen3,
E. Jolley3,
R. Miller4,
R. Dixon5,
D. Bailey6
(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