Current economic conditions are forcing exploration managers to reduce acquisition costs of geological and geophysical data. Well-cuttings provide a virtually untapped source of inexpensive geological information.

A computer-aided system for the study of petrographic data from well-cutting thin sections, developed by the author in the early 1970s, provides a practical methodology for creating a digital data base. A choice of 77 attributes which include lithology, depositional fabrics, diagenetic fabrics, fossil content, nonskeletal grain types, fractures, porosity, and porosity types can be digitally encoded.

The method is very cost effective and can generate reports and interpretations in real time. The digitally captured data is saved to a floppy disk, and a program was developed which reads the file, generates an alpha/numeric log, and displays histograms of all the observed attributes on a single line. The symbols used are mnemonic and easy to remember. The advantage of the single-line display is that the log can be pasted next to a geophysical log, and comparison of the two can provide a basis for interpretation of environments of deposition and diagenetic over-prints. The log is a data matrix displaying interesting patterns which can help in recognizing shoaling-upward cycles, regressive/transgressive sequences, and unconformities.

About 40-50 thin sections representing 400-500 feet (assuming 10-foot sampling intervals) can be processed per day. Over 200,000 feet of cuttings from wells in many of the petroliferous and prospective basins worldwide have been logged by the author. These include the Permian Basin, Anadarko Basin, Gulf Coast Mesozoic, Eastern Gulf of Mexico, Williston Basin, Paradox Basin, Michigan Basin, Appalachian Basin, Atlantic OCS, Bahamas, North Sea, Persian Gulf, South China Sea, Ethiopia, and Tunisia.

Applications of this type of log to exploration problems are numerous and include:

1. Generation of paleoenvironmental maps
2. Interpretation of geophysical logs in context of depositional environments and diagenesis
3. Recognition of reservoir facies
4. Calibration of seismic stratigraphic interpretations

Several examples will be shown from the Permian Basin, the Gulf Coast, Atlantic OCS, South China Sea, and Tunisia. In summary, the system developed is unique and, at a very low cost, can provide the explorationist with a wealth of geological information which heretofore has been grossly underutilized.

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