摘要
地面核磁共振(SNMR)方法是直接探查地下水的地球物理新方法。本文概述了SNMR方法原理和弛豫、间歇时间等概念,详细讨论了纵向弛豫时间常数T1和横向弛豫时间常数T2及其与多孔介质孔隙大小、孔隙表面和液体磁性的关系,提出了一个假设:表面弛豫率ρ与岩石的磁化率κ和剩余磁化强度Ir成正比。还讨论了测量仪器的间歇时间对SNMR方法测量结果的影响。在上述论述的基础上,介绍了利用SNMR方法的定量解释结果来估算孔隙度和渗透率的方法。最后,在肯定SNMR方法可给水文地质学家提供有关信息的同时,还就SNMR方法应注意磁性对观测结果的影响、研制新仪器时需要改进和提高的几个技术问题提出建议。
SNMR is a new geophysical method for directly detecting underground water. A breif account of the principle of the SNMR and concepts of relaxation and relay time are given. The relations of longitudinal relaxaion time T1 and transverse relaxaion time T2 with pore size and magnetic property of pore-surface and fluid of porous medium are discussed in detail. We presented a proposal that surface relaxivity ρ is proportional to the magnetic susceptibility κ and the remanent magnetization Ir of rocks. On the basis of above arguments, methods of estimating porosity and permeability are described. It is confirmed that SNMR method can give hydrologists the concerned information. Some suggestions about taking account of influence of magnetic property of rocks on mesurement and improving design of new instrument are made.
出处
《工程地球物理学报》
2006年第1期1-8,共8页
Chinese Journal of Engineering Geophysics
关键词
地面核磁共振
表面弛豫率
孔隙度
渗透率
延迟时间
surface nuclear magnetic resonace
surface relaxivity
porosity
permeability
delay time
