岩石孔隙结构与渗流特征核磁共振研究综述

Review of nuclear magnetic resonance technique based study on pore structure and seepage characteristics of rock

准确评价岩石的孔隙结构与渗流特征对于制定安全高效的能源开采实施方案具有重要的指导意义。以分析核磁共振技术在研究岩石孔隙结构和渗流特征方面的应用现状和发展方向为目标,在简要介绍传统测量方法的基础上,通过对大量文献的研究分析,综述了使用核磁共振技术(NMR)测量岩石孔隙结构与渗流特征的发展历史、研究成果及研究现状等内容,分析了核磁共振技术的基本原理、适用范围及优缺点,指出了目前研究的局限性及需要进一步研究的内容。结果表明:核磁共振技术在能源地质、生命科学、航空航天等众多领域均有广泛应用。在岩土工程领域,该技术可以快速、准确的测定岩石的孔隙率、渗透率、可动流体饱和度等基本物性参数,当岩芯中有流体时,能直观地观测到岩芯内流体的渗流过程,为后续多孔介质微观孔隙结构的研究提供了新思路;在岩石孔隙结构与渗流特征研究方面,核磁共振技术与传统研究方法相比具有其独特优势,但是岩芯中顺磁物质及含氢物质的存在使得测量结果与实际情况存在一定的误差。因此,今后的研究应致力于减小这些因素对测量结果的影响,同时建立渗流过程中不同时刻流体渗流量与渗流特征的函数关系。

Accurately evaluating the pore structure and seepage characteristics of rock has important guiding significance for the development of a safe and efficient energy extraction implementation program. By taking the analysis on the status of the application of the nuclear magnetic resonance（ NMR） technique to the study made on the pore structure and seepage characteristics of rock and its development direction as the study objective,the development history,study results and study status of the application of the NMR technique to the measurement of the pore structure and seepage characteristics of rock are reviewed herein through the study and analysis on a large amount of relevant literatures on the basis of brief introduction of the conventional measurement methods,and then the basic principle,scope of application and merits and defects of the NMR technique are analyzed,while the limitations of the current study and the contents to be necessarily and further studied are pointed out as well. The result shows that the NMR technique can be widely applied to many fields,such as energy geology,life sciences,aerospace,etc. In the field of geotechnical engineering,the basic physical parameters of rock,i. e. porosity,permeability,movable fluid saturation,etc. can be quickly and accurately measured. When fluid is there in rock core,the seepage process of it can be visually observed,which provides a new idea for the subsequent study on the microporous structure of porous medium. In the aspect of the study on the pore structure and seepage characteristics of rock,the NMR technique has its unique advantage if compared with the conventional ones,but the presences of paramagnetic matter and hydrogen-containing substances in rock core cause certain errors between measurement result and actual condition. Therefore,the reduction of the influences from those factors on the measuring results must to be focused in the future study concerned,meanwhile,the function relations between both the seepage volume and seepage characteristics at different instants of time in the seepage process must be established as well.