ABSTRACT

Many studies have been conducted to analyse dielectric polarisation and the complex electrical conductivity characteristics by the Cole–Cole type relaxation approximating rocks with a uniform material. That method has revealed the correlation between metal contents and chargeability, between the central relaxation time and the metallic particle size, and so on. Based on the model’s success, such models have been extended to those with multiple capacitances. However, these models cannot represent the mechanism of electrical flow in rocks using equivalent circuits and cannot explain the electrical behaviour of rocks that deviates significantly from the assumptions of the models. Therefore, in this study, by re-evaluating Pelton’s equation, we strove to formulate an appropriate multiple-capacitance model expressed by an equivalent circuit, with the aim of ascertaining electrical features more easily and properly than through the convolution of electrical response functions. We achieved theoretical expansion of Pelton-type formulae to multiple capacitances. Our Double-Pelton equivalent circuit model (DPM) was applied to the observed complex conductivity curves of artificial samples including pyrite. The obtained parameters of our DPM were found to have a good correlation to the rock features. We achieved to show that the conductive mechanism of the complex geometrical features of rock samples can be modelled simply and effectively. The continuous efficiency of sulphide particles in the direction of the electric field, and pyrite particles which can act as bottleneck conductors as in percolation theory, are found to be playing an important role in electric conduction.

摘要

已经进行了许多研究，通过使用均匀材料近似岩石的科尔-科尔型弛豫来分析介电极化和复杂的电导率特性。该方法揭示了金属含量与带电性之间、中心弛豫时间与金属颗粒尺寸之间的相关性等。基于该模型的成功，此类模型已扩展到具有多个电容的模型。然而，这些模型无法使用等效电路来表示岩石中的电流机制，也无法解释与模型假设显着偏离的岩石的电行为。因此，在本研究中，通过重新评估 Pelton 方程，我们努力建立一个用等效电路表示的适当的多电容模型，目的是比通过电响应函数的卷积更容易、更正确地确定电特征。我们实现了佩尔顿式公式到多个电容的理论扩展。我们的双冲击式等效电路模型 (DPM) 应用于观察到的包括黄铁矿在内的人造样品的复杂电导率曲线。我们发现 DPM 获得的参数与岩石特征具有良好的相关性。我们的成果表明，可以简单有效地对岩石样品复杂几何特征的传导机制进行建模。人们发现，硫化物颗粒在电场方向上的连续效率以及在渗流理论中可充当瓶颈导体的黄铁矿颗粒在导电中发挥着重要作用。