Nuclear magnetic resonance as a geophysical tool for hydrogeologists
Nuclear magnetic resonance as a geophysical tool for hydrogeologists
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DOI：
10.1016/s0926-9851(02)00128-3
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发表时间：
2002-05-01
影响因子：
2
通讯作者：
Bernard, J
中科院分区：
文献类型：
--
作者：
Legchenko, A;Baltassat, JM;Bernard, J
质子磁共振测深（MRS）是一种专门为水文地质应用而设计的地球物理技术。它基于核磁共振（NMR）原理，可以对地下自由水进行非侵入性检测。与许多其他地球物理方法一样，MRS取决于场地。建模结果表明，MRS的性能取决于天然地磁场的大小、岩石的电导率、电磁噪声等因素。例如，现有设备的地下水探测最大深度可从45米到170米不等，这取决于测量条件，尽管一般认为平均探测深度约为100米。MRS数据的处理可以提供含水层的深度、厚度和含水量。根据MRS提供的含水量和弛豫时间T-1和T*（2），结合使用钻孔抽水试验数据进行的校准，可以估计含水层的水动力特性，即渗透率、渗透率和单位产量。为此，将核磁共振测井的经验应用于核磁共振测井资料的解释中，并将井中抽水试验结果与核磁共振测井实验结果进行了对比，结果表明两者具有良好的相关性。在沙特阿拉伯的MRS调查的一个例子。研究区面积约1.3平方公里，下伏一个由断裂展布岩组成的含水层。7次钻孔抽水试验和13次MRS测量结果吻合较好。(C)出版社：Elsevier Science B. V.
The proton Magnetic Resonance Sounding (MRS) is a geophysical technique specially designed for hydrogeological applications. It is based on the principle of Nuclear Magnetic Resonance (NMR) and allows the non-invasive detection of free water in the subsurface. As with many other geophysical methods, MRS is site-dependent. Modeling results show that MRS performance depends on the magnitude of the natural geomagnetic field, the electrical conductivity of rocks, the electromagnetic noise and other factors. For example, the maximum depth of groundwater detection for currently available equipment can vary from 45 to 170 m depending on measurement conditions, although an average depth of investigation is generally considered to be about 100 m. The processing of MRS data can provide the depth, thickness and water content of aquifers. Based on the water content and the relaxation times T-1 and T*(2) provided by MRS, in association with calibration using borehole pumping test data, it is possible to estimate the aquifer's hydrodynamic properties, namely permeability, transmissivity, and specific yield. In this aim, experience gained through NMR logging has been applied to MRS data interpretation and a comparison between the results of borehole pumping tests and those of MRS experiments reveals a good correlation. An example of an MRS survey in Saudi Arabia is presented. The study area is some 1.3 km(2) and underlain by an aquifer composed of fractured diorite. The results of 7 borehole pumping tests and 13 MRS measurements show good agreement. (C) 2002 Published by Elsevier Science B.V.