The effect of thermal damage on the electrical resistivity of sandstone

Abstract

In order to study the effect of thermal damage on the electrical property of sandstone, an electrical resistivity test is carried out with an electrical instrument. The prepared cylindrical samples are successively heated to target temperatures (i.e. 100 °C, 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C and 800 °C) at a fixed slow rate and gradually cooled down to room temperature at the same rate. The test results show that the resistivity of the sandstone samples increases gradually with the increasing temperature, and increases drastically between 300 °C and 350 °C. The wave velocity of the samples at different temperatures is also investigated and the results show that the wave velocity reduces gradually with the increasing temperature. Special attention is paid to the fact that the wave velocity reduces more quickly at certain temperatures between 300 °C and 350 °C. It can be speculated that there is a threshold temperature between 300 °C and 350 °C.