Efficient True Resistivity Prediction and Time Optimization in PcRI Measurements: A Results-Driven Approach

This study aims to validate models developed for predicting true resistivity and water saturation indrainage capillary pressure and formation resistivity index (PcRI) measurements using porous plate methodology.The true resistivity model enables the calculation of the time required to reach equilibrium for these key parameters.To validate the petrophysical resistivity model, an extensive database was used, comprising over 12,500 data pointscollected from sandstone and carbonate rocks analysed under various fluid systems, including crude oil/water,laboratory oil/water, and gas/water. The true resistivity and water production models reliably estimated trueresistivity and water saturation as a function of time for both rock types. Based on transient drainage PcRI data, themodels can predict equilibrium true resistivity and water production, significantly reducing measurement time andaccelerating PcRI measurements by up to 63% in some cases. This optimization improves analysis timing andfacilitates data interpretation, making the models as an important tool for enhancing efficiency in laboratory PcRIanalysis. These models also have practical applications in monitoring and controlling the quality of transientdrainage PcRI data. Additionally, they support the interpretation and validation of results, ensuring a more reliableand robust petrophysical evaluation.