Print this pageThree-Dimensional Seismic Evaluation of Reservoir Continuity and Four-Dimensional Seismic Monitoring of an EOR Process
Robert J. Greaves, Joseph R. Davis
The technology of three-dimensional reflection seismology has developed to
the point where detailed mapping of some reservoir characteristics can be done
in manner useful to 
field
development. Two examples of the analysis of
high-resolution seismic data for reservoir studies are presented here.
In the first example, the reflection trace amplitude and the calculated
seismic attributes of a three-dimensional survey delineate a discontinuous
section of reservoir sand and effectively map sand thickness. When local
structure is statically removed from the seismic data, time slices through the
three-dimensional data volume are interpreted as horizon slices. By correlation
of subsurface well information with seismic character, variations in seismic
attributes on the horizon slices are interpreted as maps of lateral changes in
reservoir parameters.
The second example shows the results obtained using three-dimensional seismic
data to monitor the progress of an in-situ fireflood test. Three sets of
three-dimensional seismic data were recorded in an identical manner over the
test area during a 1-year period. Taken as a whole, the seismic data have a
fourth dimension, calendar time. By comparison and direct integration of the
data sets, it is possible to map the propagation of the fireflood in the
reservoir over time and calculate a net burn thickness map from seismic
amplitudes calibrated with post-burn core information. These examples are from
small reservoir tests related to the EOR pilots, but as the results imply, the
same combinations of three-dimensional seismic and subsurface will control can
be applied to large-scale field
evelopment.
AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.