Stratigraphic coordinates, a coordinate system tailored to seismic interpretation

Discussion and Conclusions

We have introduced the stratigraphic coordinate system, a novel framework for seismic interpretation. Our algorithm for constructing the stratigraphic coordinate system consists of two steps. In the first step, we use predictive painting to produce an implicit horizon volume that defines the first axis of the stratigraphic coordinates, aligned with reflection boundaries (seismic horizons). We obtain the remaining two axes of the stratigraphic coordinate system by solving the relevant gradient equations using an upwind finite-difference scheme. Seismic image flattening is an immediate application of stratigraphic coordinates. Other possible applications include post-stack impedance inversion, tuning analysis, spiking deconvolution, or any other process that implicitly assumes that reflectors are flat or that the seismic waveforms should be sampled vertically. In all structures but layercake geology, trace-based attributes can be biased in the presence of dipping layers. In contrast, the stratigraphic coordinate system offers a local reference frame naturally oriented to sample the unbiased seismic waveform and, hence, promises to yield more accurate waveform analysis and trace attributes.

Our implementation of stratigraphic coordinates is based on the predictive-painting algorithm, which produces the best results when traces can be predicted by their neighbors. Note that the predictive-painting algorithm may fail to capture some of the events across structural or stratigraphic discontinuities. Also, in the presence of crossing dips or incoherent events, predictive painting is susceptible to errors and warrants further improvement.

Stratigraphic coordinates, a coordinate system tailored to seismic interpretation