Application of electrical rock typing for quantification of pore network geometry and cementation factor assessment

Abstract

Rock typing with its various applications reduces the required time and cost for petrophysical analysis by categorizing similar rocks into distinct groups. Rock typing is divided into different categories, one of which, is electrical rock typing. An application of static electrical rock typing is cementation factor prediction which significantly affects fluid saturation estimation. Many factors, such as pore geometry, affect cementation factor in various means. Hence, achieving an explicit correlation to compute it as a function of these affecting factors is difficult. However, examining petrophysical properties which influence cementation factor is feasible. In this study, two definitions of formation resistivity factor are merged to achieve the cementation factor correlation as a function of effective cross-sectional area, porosity, and electrical tortuosity. To determine effective cross-sectional area and electrical tortuosity in wellbore through a time-efficient and inexpensive method, electrical rock typing is used. The results of this study reveal that Kozeny's factor is perfectly correlated with effective cross-sectional area and electrical tortuosity. Therefore, effective cross-sectional area and electrical tortuosity are computed throughout the wellbore. Moreover, investigating the relation between flowing porosity and rock capacity for transmitting electricity shows that they are directly related. Cementation factor and stagnant porosity also have a direct relationship. The findings of this study aid the assessment of porous media for attaining a clear understanding of petrophysical properties relationships, and their impact on porous media capability for storing and transferring fluid and transmitting electricity. Determining petrophysical properties continuously in wellbore leads to a better comparison between different segments of the reservoir. Regarding the fact that all presented methods are mainly based on log responses, they are easy to apply. However, the availability of enough samples is essential to initiate the analysis. • Obtaining effective cross-sectional area continuously through wellbore. • Developing a method to determine electrical tortuosity through wellbore. • High EQI Samples have a higher flowing porosity, and a lower cementation factor. • As electrical tortuosity increases, m rises due to reduction in flowing porosity.