Summary

Integration of the seismic sequence amplitude mapping technique with seismic facies character, and with well log information over a 100ms interval enabled reconstruction of the depositional environment, identification of reservoir units, and analysis of reservoir geometry. The depositional environment was interpreted to be fluvio-deltaic, the reservoirs composed dominantly of channel sands, associated point bars, thin crevasse splays, and thin sand bars.

Areal distributions of porosity, net sand thickness, gas saturation, and hydrocarbon pore meter (HPM) were predicted through kriging and cokriging methods using data at well locations and using specific seismic attributes. The predicted maps show high porosity and high sand thickness trends to relate to the main channel reservoir geometries. Predictions of gas saturation and HPM distributions show potential hydrocarbon accumulations to concentrate in channel sands at fault traps and at small stratigraphic traps. The gas-water contacts were mapped using the predicted gas saturation value of 50%, or the predicted HPM value of greater than 3.

The predicted maps obtained through cokriging provided better subsurface descriptions than those estimated through kriging or through kriging with external drift, KED. Cross validations, error maps and conditional simulations proved the cokriging method to have better accuracy than kriging and KED.

The study revealed that while seismic data could be used independently to estimate hydrocarbon and petrophysical parameter distributions (through attribute anomalies), the integrated geostatistical evaluations provided better constrained distributions. Comparisons with new drilling information showed very good similarities between the predicted and true values.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah