Application of old electric logs in the analysis of Aux Vases Sandstone (Mississippian) reservoirs in Illinois

Old electric logs (pre-1960) are a valuable source of information for the oil industry to use for improved and enhanced oil recovery. In this study, old electric logs were used effectively to estimate porosity and water saturation. The empirical methods described in this report are quick and easy to use. Results of the analysis can be applied to identifying passed-over pay in older wells and as input into reservoir models. Three methods for using old electric logs to estimate the porosity of the Aux Vases Sandstone (Mississippian) were tested for wells in Jefferson, Wayne, Franklin, and Hamilton Counties in Illinois. The empirical normalized spontaneous potential method was significantly better at predicting porosity than were the short normal or Rocky Mountain methods. -from Author