Abstract：There is close relationship between the dispersion character of complex resistivity and the observed frequency in rocks. It is shown by studying the mechanism of which the dispersion character of complex resistivity in rocks is relative to induced polarization in low frequencies. We carried out numeric simulation of complex resistivity in low frequencies for dual lateral electrode array and discovered the spatial surveying characters of complex resistivity logging in borehole environment only depend on the structure of electrode array; the frequency characters of logging response resulted from borehole environment are as same as the rule reflected by numeric simulation test of dispersion character of complex resistivity in rocks. Therefore, the paper presented conception about new dual-frequency complex resistivity logging: the dual lateral electrode array is used in electrode array; the complex resistivity values and phase angles of logging responses in low and high frequencies are picked up respectively in logging; the in-phase and out-of-phase resistivities are computed by complex operational relation, which are effectively used for evaluation of oil-gas reservoir.
