The transformed propagation resistivity from commonly used one-dimensional model is affected largely by high salinity drilling fluid, and the change trend of amplitude ratio resistivity and phase shift resistivity is sometimes different. High salinity drilling fluid and large resistivity contrast between the virgin formation and drilling fluid may make the measurement over range. The improved transformation model takes the borehole radius and drilling fluid resistivity into account, so as to correct the borehole influence in real time. The borehole size can be obtained by ultrasonic, neutron, nuclear density tool, the amplitude ratio resistivity and phase shift resistivity transformation charts were calculated and saved as transformation database.
Oklahoma formation model was used to validate the effectiveness of the real time borehole correction method, and an ideal formation model was also built to validate the usability of the method in highly deviated wells. The results show that the method proposed in the paper can reduce the borehole influence, decrease the calculation dimension and improve the inversion efficiency of highly deviated and horizontal well logging data.