For use in quantitative log analysis, SP correction charts were constructed from data taken on a resistor network analog for various cases of invaded and noninvaded thin beds. An abrupt transition was simulated between invaded and noninvaded zones. Batteries were inserted at appropriate locations in the high impedance network to simulate the electrochemical emf's contribution to the SP. The correction curves are presented in a form considered to be easily usable by the working log analyst. Examples of their use are shown. Various factors to observe in the application of the charts are discussed.