高精度海底沉积物四点电极电阻率探针研究

Research on the high precision resistivity probe with four point-electrodes for marine sediments

海底沉积物的电阻率是现代海洋地球物理探测的重要参数。针对海底沉积物电阻率高精度测量的难点,对环形Wenner排列四点电极电阻率测量技术进行研究。利用有限元方法在有限空间柱状样内对该探针电极产生的电场强度进行仿真,并进一步实现了探针结构的优化。然后将现有文献中的电极配置因子进行了校正,以使其适用于非理想点电极且沉积物样品为有限空间时的情况。最后利用该探针进行标准KCl溶液的电导率测量实验,用以进一步验证该探针的测量精度。实验证明该技术操作方便,实用可靠,其测量相对误差小于1%。

The resistivity of the marine sediment is an important parameter in modem marine geophysical survey. Aiming at the difficulties in high precision measurement of marine sediments resistivity, this paper conducted the re- search on resistivity measurement technique of the circular Wenner probe with four point-electrodes. The electric field intensity on the probe electrodes in the limited space inside the cylindrical sample was simulated by using the finite element method, and the optimization of the probe structure was realized. Then the electrode configuration fac- tor in the existing literatures were corrected in order to make it applicable to nonideal point-electrode and sediment samples in the limited space. Finally, combined with the experiment of the probe to a standard KC1 solution the ac- curacy of the probe was further verified. It is proved that this technology has the advantages of convenient, practical and reliable, and the relative error of measurement is less than 1%.