Abstract：The paper studied varying rule for rock resistivity in lithoelectric-phase displacement process using numerical modeling method for water drive model. The studied results show that the relational curves between rock resistivity and water saturation in waterflooded process basically are sigmoidal,and U-type curves usually seen currently abroad only are a special case of sigmoidal curves. The paper calcufated the effect of reservoir property and water injected resistivity on curve types by numerical modeling and provided a reliable theoretical basis for correct evaluating waterflooded rule of reservoir and interpreting remaining oil saturation.
