Analyzing shaly sand formations is complicated even with modem logging suites accompanied with core or CEC data. However when only older logs are available the analysis must be made with fewer models and comparative calculations. This paper outlines several methods for analyzing older electric logs including: computing effective porosity computed from resistivity curves, computing water saturation using the No Porosity Automatic Compensation Model (Asquith, 1990), and Dual Water No Porosity Model (Elphick, 1988), using statistical crossplots, and correlating GR and SP curves to curves from new wells having Cation Exchange Capacity data to utilize the Waxman-Smits Method for estimating water saturation. Examples from two wells are presented to illustrate a procedure for obtaining reliable results from old electric logs.

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