PSEUDOSEISMIC TRANSFORMS OF WIRELINE LOGS: A SEISMIC APPROACH TO PETROPHYSICAL SEQUENCE STRATIGRAPHY
JOHN F. HOPKINS, TIMOTHY R. CARR, HOWARD R. FELDMAN, 1996. "PSEUDOSEISMIC TRANSFORMS OF WIRELINE LOGS: A SEISMIC APPROACH TO PETROPHYSICAL SEQUENCE STRATIGRAPHY", Stratigraphic Analysis Utilizing Advanced Geophysical, Wireline and Borehole Technology for Petroleum Exploration and Production, Jory A. Pacht, Robert E. Sheriff, Bob F. Perkins
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Stratigraphic interpretation from wireline logs is typically drawn from multiple log traces or from crossplots of log data. Both techniques can readily depict vertical changes in lithology or reservoir quality, but lateral relationships are not readily visualized. Significant improvement in the geologic interpretation of wireline log data can be achieved through transformation and treatment of the transformed data as “seismic” traces for the purposes of processing, interpretation, and display. This combination of wireline logs with a seismic interpretive approach is labeled pseudoseismic. The pseudoseismic transform can combine data from multiple logging tools, generating a convolved ‘crossplot log’ for each well. A well-designed transformation of wireline log data across multiple wells maximizes both spatial and compositional information contents and provides a readily interpretable image of the subsurface geology. Various filters and transformations can be applied to emphasize different aspects of the subsurface geology.
The transformed wireline log data are loaded into a computer workstation and interpreted as a set of 2D pseudoscismic traces or as a 3D pseudoseismic volume. Use of interpretation and visualization packages developed for seismic data offers flexibility in displaying and picking horizons, and increased efficiency of sequence stratigraphic interpretation. The treatment of wireline logs as a data volume permits comprehensive and cost-effective sequence stratigraphic and reservoir analysis of data sets that were previously considered intractable.
Examples from western Kansas, at both the regional and field scale, illustrate the utility and efficiency of sequence stratigraphic interpretation using the pseudoseismic approach. The pseudoseismic approach to the analysis of wireline log data from multiple wells opens new dimensions in log interpretation and provides significant insight into complex stratigraphic geometries associated with lithology, reservoir quality, and fluids.