Abstract

By making detailed comparisons with core data from a well located on a crosswell seismic profile, we examine the vertical resolution of crosswell seismic data from a geologic perspective. Whole-core porosity and permeability measurements are highly variable in our example and are not obviously related to core-based lithofacies. The disconnect between reservoir quality and depositional lithofacies is caused by a complex diagenetic overprint, primarily cementation by evaporites. Changes in porosity and mineralogy (predominantly gypsum and siliciclastic abundance) relate directly to the numerous crosswell seismic events. Although major stratigraphic boundaries (sequence boundaries and flooding surfaces) generally coincide with reflectors, lithofacies and small-scale depositional cycles recognized during the core description do not relate directly to the seismic data. There are strong indications that crosswell seismic data can be an important tool for assessing reservoir variability.