Abstract

Vacuum Field in Lea County, New Mexico is a mature, multi-pay field set in a carbonate platform and provides an ideal case study of the effects of seismic processing flow on the geologic interpretation of 3-D seismic data. We compare the data quality and multitrace seismic attributes resulting from two seismic processing workflows of a conventional 3-D survey collected over Vacuum Field. Stacked carbonate layers are commonly characterized by high seismic velocities, which result in low vertical resolution, and relatively small changes in impedance, which in turn results in low internal reflectivity and correspondingly low signal-to-noise ratios. Seismic attributes including coherence, dip azimuth, and amplitude gradients are often effective in imaging subtle and small-scale geologic features that are much more difficult to discern on the seismic amplitude data directly. For this reason, we find that the evaluation of the image quality of subtle laterally variable stratigraphic features is possible, and most easily achieved by the use of multitrace attributes. In the absence of easily identifiable reflector terminations at faults, it is easy to sacrifice lateral resolution in an effort to suppress acquisition footprint and improve the overall signal-to-noise ratio. The optimization of certain processing steps, including ground-roll suppression, deconvolution, statics correction, and velocity analysis can have a first-order effect on such seismic attributes. We are currently reprocessing the prestack shot gathers. We are using an interpretation-driven workflow, with parameters chosen to optimize the appearance and lateral resolution of stratigraphic features as seen on attribute extractions along horizon slices. We present our findings through images of faults, channels, slumps, and other geologic features in an effort to better understand the reservoir compartmentalization.