CSAMT中E_x视电阻率与E_x/H_y比值视电阻率的对比

A comparative analysis of E_x apparent resistivity and E_x/ H_y ratio apparent resistivity in CSAMT

常规CSAMT勘探是利用电场与磁场的比值来计算卡尼亚视电阻率。通过均匀半空间及层状介质模型,对CSAMT各场分量进行了计算,对视电阻率定义方式进行了分析。研究结果表明:采用电场Ex单分量定义的视电阻率,可以减轻比值视电阻率近区畸变严重的问题。实测资料分析结果进一步验证了Ex分量视电阻率的这一优点。在野外CSAMT资料采集时不必拘泥比值视电阻率这一种定义方式,可以根据野外实际条件灵活地调整采集方式,提高工作质量和效率。

Currently, the adoption of the ratio of electric field and magnetic field to calculate the Cagniard resistivity is widely used in traditional CSAMT exploration. However, an analysis of the electromagnetic field components and the apparent resistivity definition method in homogeneous half space and layered media indicates that the apparent resistivity defined by electric field Ex component can improve the problem of the near zone distortion of ratio apparent resistivity. Moreover, the advantage of apparent resistivity defined Ex component has been further verified by the measured field data. Therefore it's not necessary to rigidly stick to using the ratio apparent resistivity in the field CSAMT data acquisition, and the acquisition mode flexibility can be adjusted according to actual conditions so as to improve work quality and efficiency.