Reservoir Description from Seismic Lithologic Modeling, Part 2: Substantiation by Reservoir Simulation

Marc De Buyl, Tom Guidish, Shahid Ullah

Two independent reservoir models were constructed for an oil-bearing channel-sand reservoir in the Taber-Turin area, Alberta, Canada. The first reservoir description was based on log and core data from six producing and two dry wells drilled within a part of the field on which a three-dimensional seismic survey was acquired. The second reservoir model was supplemented by petrophysical parameters derived from seismic lithologic modeling of the three-dimensional seismic reflection data.

This new forward seismic lithologic modeling technique can unravel the wavelet interference effects of closely spaced reflectors and allow reliable estimates of reservoir parameters for thin intervals. In this study, a detailed geologic model of the reservoir, enhanced by the results of the lithologic modeling technique, was constructed. This model depicts subtle structural and stratigraphic features that cannot be mapped from the available well data. Structure maps of the top of the reservoir and maps of the petrophysical parameters of the producing interval were developed. These include thickness, interval velocity, porosity, and porosity-thickness maps.

The increased accuracy in predicting reservoir variation attained by incorporating seismic control is demonstrated by comparing the projections of respective model parameters at two new well locations that were not included in the modeling.

A 20% increase in the calculated pore volume by the seismic-based method over the well-only approach will potentially influence economic decisions to be made in field development. The location of further development drilling and the planning of secondary-recovery methods will benefit greatly from the seismically enhanced information developed in this study.

AAPG Search and Discovery Article #91035©1988 AAPG-SEPM-SEG Pacific Sections and SPWLA Annual Convention, Santa Barbara, California, 17-19 April 1988.