科研之友
微信
新浪微博
Facebook
分享链接
摘要
A fully automated versatile device is presented for analysing the anisotropy of both seismic and electrical properties on cylindrical rock samples. Initially devoted to the study of P-wave velocity anisotropy (APV), the system has been upgraded to allow the measurement of electrical conductivity anisotropy (AEC) as well. The improved setup allows for the estimation of the APV and AEC, from measurements across multiple diameters with an angular spacing selected by the operator. In order to determine the APV simplified tensor and the true AEC tensor, at least three mutually orthogonal samples are required. Switching from velocity to electrical measurements only requires replacing the pair of ultrasonic transducers by a pair of electrodes. Whereas the procedure is quite straightforward for the P-wave velocity analysis, different calibration steps and approximations are required in the processing of the electrical data. As an example the methodology was applied to a set of two rocks, the Leopard and the Castlegate sandstones, for which the APV and AEC are compared in a unified scheme. Good agreement was found between the orientation of the symmetry axes for both properties, suggesting that in the studied rocks pore space anisotropy accounts for both velocity and electrical anisotropy. This methodology can also be incorporated into a core analysis workflow to obtain a first-hand assessment of the rock fabric orientation and anisotropy with respect to seismic and transport properties. The information thus obtained can be used as a screening step for sampling and stress testing as well as for direct core to log integration and cross-property correlations.
- 出版日期2017-9
