DASSEL: Dip Analysis by Single Sedimentary Event Location

Milton B. Enderlin, Charles S. Edmiston, David S. Epps

Numerous geophysical logging tools are sensitive to differing properties of subsurface rock formations. Some of these devices are three-, four-, and six-arm dipmeters, borehole televiewers, indeed, any device that senses discreet points around the wellbore and orients them with respect to the earth's frame of reference. From the tool response record, the worker is capable of extracting detailed geologic information. One of the primary aims of analysis of these three-dimensional logging tool responses is the determination of the true dip of some bedding feature or sequence of features, in order to derive structural or stratigraphic information.

Geologic analysis of computed dipmeter results is commonly being performed by nongeologists who may lack a full appreciation of the geologic significance of the feature of interest, thereby misinterpreting the data by not using fundamental geologic reasoning. Geologists should be the ones to decide what events in the tool record represent significant geologic features.

We propose a method that uses any tool response record to enhance geologic analysis. The method (DASSEL--dip analysis by single sedimentary event location) shows geologists how to utilize their training and education to determine which events in the raw tool record have structural or stratigraphic geologic significance. Furthermore, the method lets the geologist spatially orient the significant features, whether planar or nonplanar. Additionally, one may validate the quality of machine correlations and computed results using the techniques proposed, and in the process assume responsibility for geologic interpretations.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.