Janet Almond1,
Dave Taylor2,
Huw Williams3,
Gary J. Hampson4,
Howard D. Johnson4,
Steve R. Taylor1
(1) Shell UK Exploration & Production, Aberdeen, United Kingdom
(2) Esso Exploration & Production, Leatherhead, United Kingdom
(3) Reservoir Geology Consultants Ltd, Rhandirmwyn, United Kingdom
(4) Imperial College, London, United Kingdom
Abstract: Exploiting remaining oil in mature shoreface sandstone
reservoirs: an example
from the Brent
Field
, UK North Sea
Most major North Sea oil fields are now in advanced
production decline.Maximising recovery and value in such reservoirs requires
the integrationof (1) static and dynamic reservoir data
, (2) quantitative
data
fromoutcrop analogues, (3) concepts for predicting high-resolution 3D reservoir
architecture, and (4) 3D reservoirmodelling tools. We illustrate this with an
example
from thewave-dominated, shoreface/delta front sandstones of the Brent
Group(Rannoch Formation) in the Brent
Field
. The Rannoch Formation was
originally viewed as a simple coarsening upward, laterallyextensive and
relatively homogeneous reservoir, with only minorthree-dimensional permeability
heterogeneity. However, production haslagged behind that of other reservoirs
during the
field's
23-year production life, due to the water injection scheme
havingpreferentially swept the overlying, higher permeability coastal barrier
andvalley fill sandstones (Etive Formation). Detailed sedimentological
studiesof core and wireline log
data
reveal subtle variations in bioturbation,
mineralogy and mica content, whichdefine a composite succession of prograding
shoreface deposits, includinggently dipping ( < 1 degree) clinoforms.
Variations in clinoform geometryand spatial arrangement not only record
evolving depositional processes, including syn-depositional tectoniccontrol on
shoreline orientation, but also impart a strong control onpermeability
anisotropy. High-resolution dynamic reservoir simulations havebeen undertaken,
which preserve the clinoform-based geological model and its associated
permeability anistropy.Results have helped define areas of bypassed oil that
are now beingtargeted by infill wells, thereby contributing additional value to
thecurrent late stage of oil development in the Brent
Field
.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana