Irreducible water saturation determination based on centrifugal test data

Key words:  irreducible water saturation  three-water conductive model  centrifugal method  free water

Abstract:

The rock conductive path was paralleled by free water, micro-porous water and clay irreducible water. The change of rock resistivity was caused by the change of conductive ability of free water. Based on three-water conductive model，a novel method of calculating irreducible water saturation was proposed in order to get accurate results. The calculation formula of irreducible water saturation was derived with centrifugal test data, and its correctness and reliability were verified by semiper-meable membrane data. The application results show that irreducible water saturation calculated by this method agrees well with the results of mercury injection and relative permeability analysis. Compared with traditional centrifugal method, the accuracy of the mehod was obviously improved.