Abstract: Seismic Characterization of Upper Carboniferous Reservoirs by Means of Image Processing and Geostatistics

HELLMICH, CARSTEN, and HENNING TRAPPE

By means of 3D seismic data a lithology prediction of Upper Carboniferous fluvial reservoirs within the North German Basin has been carried out. The target depth is about 3000m. The zone of interest is defined by the first 25m of the Upper Carboniferous below Base Zechstein. Obtaining porosity information through amplitude relationships proofed to be difficult. The problem is an overlapping range of acoustic impedances of the dominating shales and the porous sandstones.

The problem was attacked by a new approach: Seismic attributes were extracted by image processing algorithms in addition to seismic amplitudes. These multitrace filters compute neighborhood statistics for each point on the amplitude map. As the result parameters such as `entropy' and `dispersion' were derived. In the next step relationships to log parameters were established in the vicinity of key wells. In this way it can be shown that the multitrace filters reflect lithology changes at reservoir depth.

Geostatistical variogram analysis was done to establish anisotropy and range of the seismic attributes. Co-Kriging and Co-Simulation combined well data and seismic attributes in a final step.

The results show the lithology distribution derived by image processing of seismic data combined with geostatistics. These maps may now serve for reserve estimation.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria