An approach for minimizing errors in computing effective porosity in reservoir of shaly nature in view of Wyllie-Raymer-Raiga relationship

► The proposed second order-Vsh model treats the effect of shaliness as a correction term subtracted from the clean-sand term. ► It can still be applied with high accuracy for evaluating effective porosity in old wells. ► It can be considered as a quick-look approach in interpreting the recent exploratory wells before the decision of completing the logging measurements.