Simultaneous Recording of Mud Resistivity Log and Usual Electrical Logs

Abstract

The estimated value of the subsurface mud resistivity, which is calculated from the surface sample mud data with the correction to the temparatare only, seems to the writer to involve some uncertainties. Because, the themical composition of the mud in place may be not necessarily same as that of the mud sample.
And therefore, the writer has developed the new device which can record simultaneously SP, short normal resistivity (30cm), long normal resistivity (90cm) and mud resistivity with the quadruple cord, and tested it practically.
Some of the mud resistivity curves obtained experimentally are shown in Fig. 6. They show that the mud resistivity variation with depth is more complicated than expected solely with respect to the temperature.