Use of electric-logging methods to gain more geological information involves knowledge of the lithologic conditions which affect logging measurements. Porosity, interstitial water resistivity, water saturation, permeability, and amount of shale have a definite relation to the recorded curves.

Recent advances in interpretive techniques make possible the determination of water saturation, porosity, and producible oil index by logging methods, even in shaly sands. Qualitative permeability is indicated by the SP curve or microlog-caliper, and under certain conditions can even be determined quantitatively.

Numerous examples are presented which indicate that every permeable formation, no matter how low its resistivity, should be considered potentially oil-bearing until a complete log interpretation has been made.

End_of_Article - Last_Page 432------------