Combined Ground Penetrating Radar
(GPR) and Outcrop Studies as a Tool for Predicting
Subsurface Fluvial Architecture
Oluwatosin Akinpelu
University of Toronto, Department of Geology, Toronto, Canada
Predicting
the detailed internal
architecture of subsurface fluvial deposits has been an enigma in
reservoir
development over the last few decades. In today’s world of ever-increasing
demand for petroleum, the need for accurate handling of
reservoir
heterogeneities for optimized production cannot be over-emphasized and requires
extensive research.
The complex geometry of fluvial
sandbodies and their significant spatial heterogeneity has recently triggered a
burgeoning interest in the use of outcrop data as analogues for subsurface
reservoirs. While earlier attempts have essentially been two-dimensional,
three-dimensional outcrop studies of sub-surface reservoir
analogues combining
outcrop data and closely spaced GPR profiles hold the greatest promise for
fluvial hydrocarbon
reservoir
evaluation and development. To this end, this
project adopts hybrid techniques integrating outcrop-based architectural element
mapping of cliff faces and GPR imaging to obtain three-dimensional data from
near surface
sandstone
reservoir
analogs in a wide variety of fluvial channel
deposits from the Whirlpool Formation (Niagara Escarpment), Kayenta Formation,
Castlegate
Sandstone
(Utah) and St. Mary River Formation (Alberta). Facies
associations and their bounding surfaces are mapped on photomosaics and combined
with the GPR profiles to generate detailed three-dimensional stratigraphic
volumes which can be sliced in different directions to unravel the depositional
history of each Formation.
This project offers significant
promise in unravelling the controls on the distribution of heterogeneous facies
in fluvial deposits through studies of complex outcrop analogues. It is also of
immense application to field development and enhanced recovery projects geared
at retrieving previously untapped mobile oil due to reservoir
heterogeneities.
AAPG Search and Discovery Article #90060©2006 AAPG Foundation Grants-in-Aid