抄録
Laboratory measurements have been made of the impedance of saturated samples of Berea Sandstone and Spirit River Formation sandstone throughout the frequency range of 5Hz to 13MHz. When the data from a saturated sample are presented as a complex impedance plot the frequency dispersion produces a “non-ideal” distribution of points in the form of a depressed and slightly distorted semicircle and an inclined straight line. It is possible to separate the low frequency electrode response from the bulk sample response, thereby isolating the effect of polarization at the sample/electrode interface. The frequency response of the sample can be modelled by an equivalent circuit proposed by RAISTRICK et al. (1976) which includes a frequency dependent admittance term. Different samples and varying levels of water saturation cause changes in the complex impedance plots which can be related to this admittance term. The form of this term and its significance with respect to rock properties needs further investigation.
