不同温度下砂岩渗透性能的核磁共振响应

NMR Response of Permeability of Sandstone Subject to Different Temperatures

温度作用下研究岩石渗透性能对高温岩体工程建设具有重要意义。本文选取砂岩为研究对象,基于低场核磁共振在研究孔隙流体中无损、精细、定量化表征方面的优势,采用该技术考察了25~600℃砂岩渗透率变化。利用核磁共振方法,计算砂岩核磁孔隙参数。对比分析实测渗透率与模型之间的数值关系,评估了5种核磁共振渗透率模型。研究结果表明:SDR核磁渗透率模型可有效表征渗透率与温度的关系。不同温度下砂岩渗透率会发生改变,渗透率存在阈值温度点,在低于400℃时渗透率缓慢变化,在400℃以后渗透率显著增加。

Deeper understanding of rock permeability after high temperature treatment is of great significance to the construction of high temperature rock mass engineering.Sandstone was used as research object.With the advantage of low-field NMR in non-destructive,precise and quantitative characterization of pore fluid,we investigated the change of sandstone permeability at temperature range of 25-600℃.Based on the NMR method,the NMR pore parameters of sandstone were calculated.The numerical relationship between measured permeability and model permeability was comparatively analyzed,and five NMR permeability models were evaluated.The results showed that the SDR model can be used to characterize the relationship between sandstone permeability and temperature.Sandstone permeability changes with temperature,and there exists a threshold temperature.The sandstone permeability changes slowly below 400℃,and increases significantly after 400℃.