交流阻抗谱法及其在岩石微裂纹检测中的应用

交流阻抗谱法可以检测各种固体、液体内部以及它们界面的束缚和移动电荷的动力学行为。文中介绍了建立在阻抗概念上的技术。利用CHI600A型电化学工作站,测试了不同物理状态下砂岩的阻抗谱。结果显示:砂岩的阻抗谱分为四段圆弧。通过对砂岩阻抗谱Nyquist曲线的分析,结合前人多孔介质交流阻抗谱的研究成果知道,岩石Nyquist曲线上不同频率段的圆弧表征岩石内部不同构造层次的电化学过程。其中高频弧是一段容抗弧,表征岩石的体积特征,包括岩样内部的空隙大小、空隙连通情况以及空隙尺寸的均匀程度等的阻抗特征;并选取高频容抗弧上表示岩石微观结构的指标对砂岩的阻抗谱进行分析,建立了Nyquist曲线上的相关参数和岩石微观结构的联系,为岩石微裂纹的检测提供了新思路。

Impedance spectroscopy and application to test the microcrack of rock

The impedance spectroscopy might be used to investigate the dynamics behavior of bound or mobile charge in the bulk or interfacial regions of any kind of solid or liquid materials.The technique of impedance was introduced firstly.The impedance spectroscopy of sandstone was tested at different physical states by CHI600A electrochemical workstation.It was shown that the impedance spectroscopy of rock included four parts.To analyze the Nyquist chart of rock and the data of impedance spectroscopy of porous medium,the variation of AC impedance spectroscopy(ACIS) revealed the variation of the different inner structure of rock.The high frequency part of ACIS was one-stage capacity reactance arc which reflected the volume characteristics of rock,including the size and connection condition of rock inner pore and their uniformity.The parameters of rock microstructure in the high frequency part of ACIS were selected.The relation of the parameters of the high frequency part of ACIS and rock microstructure was established.It was a new idea to test the rock microstructure.