模拟地层条件下岩芯电阻率与温度关系的实验研究

Experimental Study on the Relations between Rock Resistivity and Temperature in Simulating In-situ Conditions

利用模拟地层条件岩芯电阻率测量仪 ,对 6块孔隙度、渗透率各不相同的砂岩岩芯 ,在一定围压条件下 ,岩芯完全饱和盐水时 ,考察了岩芯电阻率随温度的变化。发现饱和盐水岩芯的电阻率随温度升高 ,以幂函数形式下降。虽然岩芯中饱和盐水的电阻率同样随温度以幂函数形式下降 ,但岩芯电阻率的下降不能完全用岩芯饱和盐水的下降表征。胶结指数m或阿尔奇公式中的比例系数a同样受温度影响。进而表明在温度作用下 ,组成岩芯的各种矿物所发生的微观变化 。

Using the rock resistivity meter with simulating in-situ conditions,the relations between rock resistivity and temperature were observed from 6 sandstone samples with different porosity and permeability,while samples were brine water-saturated and subjected to certain confining pressure.It is found that the resistivities of water-saturated rock samples decrease in the form of power expression with the temperature increase.Although the resistivity of brine water decreases with temperature in the same rule,it can not entirely account for the decreasing of rock resistivity.The cementation factor m or the factor a in Archie's equation are affected by temperature too.Then it is indicated that the micro changes of minerals composing the rocks due to temperature will reveal in the macro properties of rocks.