基于显微CT和造影剂的砂岩静水压力细微成像初步研究  

Microscopic Imaging of the Sandstone Under Hydrostatic Pressure and Its Preliminary Analysis Based on the Micro-CT and Medical Imaging Agents

作　　者：王建美[1] 冯增朝[1] 周动 赵静[1] 

机构地区：[1]太原理工大学采矿工艺研究所,太原030024

出　　处：《太原理工大学学报》2015年第4期405-409,共5页Journal of Taiyuan University of Technology

基　　金：国家自然科学基金资助项目:固-热-水气两相流耦合作用下煤层气解吸运移机理研究(51304142);煤吸附/解吸甲烷过程的能量迁移及其控制作用机理研究(21373146)

摘　　要：为了清楚地识别砂岩岩芯内部在静水压力下结构的变化,并对其进行定量描述,深入研究砂岩的渗透特性,应用医学注射剂泛影葡胺作为砂岩渗流造影剂,通过高精度显微CT对砂岩不同静水压力下渗流进行扫描,重建了不同层面CT图像,分析被扫描试件的衰减系数,实现了砂岩显微结构和渗透过程的定量分析。试验结果表明,造影剂作为渗透流体,可更清晰地分辨渗流状态;沿试件直径方向,外部CT值增量随压力近似呈直线递增,较容易发生渗透,内部则近似呈指数递增;静水压力大于15 MPa,CT值增量明显减少,说明此压力时砂岩孔隙基本达到饱和,再增加压力,其孔隙流体的含量增加就十分微弱。本研究为多孔介质渗流研究提供了新方法。This paper aims at clearly identifying the changes of sandstone core＇s inner struc- ture under hydrostatic pressure, and obtaining a quantitative description to conduct in-depth stud- y of the permeability of sandstone. The medical injection meglumine was used as the imaging a- gent of sandstone permeation;CT image at different levels was rebuilt by scanning the permeation of sandstone under different hydrostatic pressures with high-accuracy micro-CT. By analyzing the attenuation coefficient of the scanned samples, the quantitative analysis of the microscopic struc- ture and permeation process of the sandstone was achieved. The experimental results indicate that, first, imaging agent as permeation fluid can more clearly distinguish the permeation state. Secondly, in the diameter direction of the sample, the external CT values exhibit a nearly linear increase with hydrostatic pressure, and the permeation is more prone to occur; the internal CT values increase exponentially. Thirdly, CT values significant decreases when the hydrostatic pressure is more than 15 MPa, and the permeation is less likely to take place. It illustrates that at this pressure, permeation fluid saturates the pore of sandstone, and further increase in pressure re- sulfs in less increases in water content in pores.

关 键 词：显微CT 造影剂 静水压力 砂岩 渗流过程 

分 类 号：TU451[建筑科学—岩土工程] P584[建筑科学—土工工程]