Porosity Characterization with a 3-D, 3-C Seismic Survey at Joffre Field, Alberta, Canada

John F. Arestad, Thomas L. Davis, and Robert D. Benson

Porosity detection and quantification has been difficult to achieve with seismic methods, particularly in carbonate rocks. The Upper Devonian (Frasnian), Nisku Formation dolomite in Joffre field (south-central Alberta Canada) is a reservoir where compressional seismic data has not detected porosity. Additionally, P-wave seismic data does not image an oil productive Leduc reef in the study area. Geologic core studies of this reservoir revealed depositional and diagenetic heterogeneities, which influence production. The existing well spacing does not adequately characterize its complexity. With these observations in mind, a multicomponent 3-D (3-D, 3-C) seismic survey was collected over the northeastern limit of Joffre field by the Colorado School of Mines Reservoir Charact rization Project.

Shear wave technology has characterized the variability of Niski reservoir porosity and imaged the productive reef. Velocity ratio (Vp/Vs) mapping of 3-D, 3-C seismic data is a powerful lithologic and pornsity discrimination tool. Vp/Vs ratios exhibit a linear correlation with Nisku reservoir porosities and were used to map porosity within the survey area Significant Nisku reservoir heterogeneities are depicted by the resuIts. Improved hydrocarbon recoveries will be achieved by utilizing the integrated reservoir model which links the Vp/Vs data through geostatistical analysis with detailed geologic facies and reservoir engineering data.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California