CSAMT阻抗梯度法之初探--以新疆和什托洛盖盆地为例

Preliminary study on impedance gradient method of CSAMT:An example of Heshituoluogai Basin in Xinjiang

沉积盆地中由于各岩层电阻率差异小,传统的CSAMT方法解译仅依靠电阻率资料对层位进行划分,具有多解性,探测精度难以满足要求。根据电磁波与地震波的相似性,以电磁法的拟地震波解释法理论为基础,结合CSAMT方法特点,初步研究了一维层状介质的阻抗梯度法在资料解释中的可行性。结合在新疆和什托洛盖盆地的一条实测剖面成果与多个钻孔资料的对比分析,该方法在盆地的地层结构和构造的划分中具有指示作用,与传统方法的解释效果对比,其对低阻区域分层效果明显,使CSAMT资料解释提高了测量精度。

In the sedimentary basin,due to the small difference in resistivity of each stratum,the interpretation results of the traditional CSAMT data have non-uniqueness of inversion,and the accuracy is difficult to meet the requirements.Due to the similarity between electromagnetic wave and seismic wave,based on the pseudo-seismic interpretation theory on electromagnetic method,combined with the characteristics of CSAMT,impedance gradient method of one-dimensional layer medium is preliminarily studied.Comparison of a detailed analysis of the measured section is carried out in the Heshitolugai Basin of Xinjiang with several drilling hole data,it is shown that the new method has an indication role in the division of strata and structures in the basin.To compare with the tradition method,the new one has an obvious reflection of the lower resistivity area and can improve the measurement accuracy for CSAMT data interpretation.