Relations between seismic signals and reservoir properties of deep gas reservoirs in Northwest-Germany -Wustrow member, Rotliegend

This study tries to find the petrophysical basis for correlations between reservoir properties and seismic signals calibrated with geological information for Wustrow-sediments of the Rotliegend in NW-Germany. A secondary objective consists in explaining the large scatter of permeability for Wustrow reservoir rocks of comparable properties. The correlations were ascertained in the DGMK-project 593-8, for instance to authigenic clay mineral types and permeability. The investigations demonstrate that the differences in seismic signals (amplitude, shape and lateral coherency of seismic traces) are a product of distinct compressional field velocities (from wireline logs) and attenuation processes as in-situ bulk densities are barely varying within the investigated horizon. The regions of different clay mineral authigenesis (illite and chlorite) diverge by their average compressional in-situ speeds. The differences suffice to provoke relevant variations in seismic signals