3-D broad-band estimates of reflector dip and amplitude

Estimates of seismic coherence of 3-D data sets have provided a radically n ew way of delineating detailed structural and stratigraphic features. Covar iance matrices provide the natural formalism to extend the original three-t race crosscorrelation algorithm to larger analysis windows containing multi ple traces, thus providing greater fidelity in low signal-to-noise environm ents. By use of 3-D phase compensation using Radon transforms, we exploit a dvances made in the high-resolution multiple signal classification (MUSIC) algorithms, originally developed for the defense industry. All three families of multitrace attributes (coherence, amplitude, and phas e) are coupled through the underlying geology such that we obtain three fam ilies of complimentary images of geologic features that result in lateral c hanges in wave form. The phase attributes of dip/azimuth and curvature allo w us to image areas that have undergone folding or draping that can not be seen on coherence or amplitude images. The amplitude attributes allow us to image oil/water contacts or other areas of amplitude variation that may no t be seen on coherence or dip/azimuth images. Coupled with coherence and the conventional seismic data, these new multitr ace dip and amplitude data cubes can greatly accelerate the interpretation of the major features of large 3-D data volumes. At the reservoir scale, th ey will be of significant help in delineation of subtle internal variations of lithology, porosity and diagenesis. In computer-assisted interpretation , we strongly feel these new attributes will become the building blocks for the application of modern texture analysis and segmentation algorithms to the delineation of geologic features.