Laboratory Study: The Effect of Clay Mineral in Sandstone on Resistivity of Rock

Abstract

One of the cases of low resistivity pay zone in several oil and gas fields is due to the presence of shale in the sandstone. This can lead to misinterpretation of what should be a hydrocarbon prospect zone looking like a water zone. The purpose of this study was to analyze how much influence the presence of shale in the sandstones has so that it is hoped that a solution can be obtained to solve the low resistivity pay zone problem. The greater the percent volume of shale, the greater the percentage decrease in resistivity. This will result in an error reading of the Resistivity price, so that this zone the Sw price looks too high. Thus, the prospect layer of hydrocarbon can be missed. (By Pass Zone). The calculation method with Water Saturation (Sw) correction is based on the Archie formula. To overcome the deviation of the Archie formula on sandstones that contain shale, an empirical approach is used. With this approach, the corrected Sw Archie is the Sw Archie measurement that has been substituted with the Sw Archie parameter and the volume of shale and shale. The empirical equation of the research results is presented in the form of the relationship between shale volume and water saturation. To validate the results of the Corrected Sw Archie calculation, other methods are needed, including: Sw Archie, Indonesia, Simandoux as comparative data. Meanwhile, Sw measurement as reference data. The comparison results show that Sw Archie is corrected to the closest measure to Sw.