地面核磁共振响应数值模拟研究

NUMERICAL SIMULATION OF SURFACE NMR

模型响应的数值计算是地面核磁共振勘探的一个重要组成部分 ,作者在本文中给出了地面核磁共振数值计算方法。在文中 ,作者借助直接数值积分方法 ,对回线源产生的磁场轴向和垂向分量进行计算 ,并采用不等间距空间坐标剖分技术 ,对地面核磁共振积分方程进行数值积分。利用这些计算方法 ,计算了在均匀导电半空间中的某一深度上 ,磁场的垂向分量沿轴向变化曲线 ,并给出了两层导电模型中存在一层含水层的地电模型的地面核磁共振响应的数值模拟结果。采用在本文中介绍的数值计算技术 ,可成功地进行一维含水模型地面核磁共振信号的数值计算。

To calculate the signal from the protons in aquifer is an important part of surface NMR water exploration technique. In the paper, the direct numerical integration for Hankel transform is applied to the computation of radial and vertical magnetic components from transmitting loop source over the ground. The non-uniform interval subdivision method is developed to integrate the signal from a single space element. With the methods, the vertical magnetic field component at certain depth was worked out along the radial direction. And the surface NMR responses from a water bearing stratum buried in different two layered conductive earth are simulated. The numerical methods utilized in the text can simulate the signals from surface NMR.