大地电磁测深相位数据的研究和应用

The research and application for the phase data of MT

MT资料处理方法近年来得到了较快发展;各种二维反演、偏移成像技术也有了新的进步。在大地电磁测深资料处理中,长期以来使用视电阻率和相位作为解释参数,但是视电阻率和相位均存在一定的局限性。该文从理论上研究了相位微分的性质,通过模型说明了相位微分的算法:先将获得的相位数据求导,得到相位微分曲线,用比较法得到曲线的极值点,通过极值点对应的周期确定主要导电层的深度和电阻率。利用相位微分能在较小的周期内得到较大的勘探深度。使用该方法对一维和二维模型进行的实验是可行的,对实际资料进行的处理结果也是令人满意的, 从而说明该方法是有效的。

MT data processing techniques including the imaging techniques and two dimensional inversion methods have been developed rapidly in recent years. In MT data processing, apparent resistivity and phase have used as interpretative parameter for a long time. However, apparent resistivity and phase have some limitations. In the paper, behavior of phase- derivative is studied. The algorithm of phase - derivative is provided by models： first we derivate the phase data, get the phase - derivative curves , use the comparison method to acquire the local maximum modulus points. Main conductive layers and resistivity are determined by the corresponding cycles of these points. Meanwhile this way could decrease the multiple solutions. We do some experimentation with 1D and 2D models in this way, believing this way is accessible. We also applied it in the field observed MT data, and get the satisfaction result, thereby prove the availability of this way.