Correlating CEC Data Between Wells – An Example


John Walsh, Susan Brown, The Logic Group, George Asquith,
Texas Tech University

SPWLA 34th Annual Logging Symposium, June 13-16, 1993



Basic Procedure Accurately interpreting well logs from shaly sand formations is complicated partly because the user must choose a water saturation model appropriate to the zone of interest. These traditional water saturation models generally require that the dominate clay type be determined and a value for shale resistivity be es- timated. An alternative way to calculate water satura- tion is by using the Waxman-Smit model which does not depend upon the clay resistivity but uses the cation exchange capacity (CEC) of the clay in computing water saturation.