三维大地电磁测深在库车坳陷库车组岩性判别中的应用

三维大地电磁测深(MT)资料用于沉积相分布的研究中,弥补了野外露头、测井和地震等传统识别和研究方法的不足.通过对三维MT资料进行去噪、编辑与平滑和静态位移校正等预处理和三维反演处理,使三维MT数据更加准确地反映研究地区岩石的电阻率.在野外露头观察和测井解释成果的基础上,利用岩芯或岩屑对电阻率进行标定,界定出库车组不同岩性的电阻率值范围,然后将三维MT剖面与相对应的地震剖面叠合,进行电震同平台解释,建立构造样式,最终在建立的地层格架内对沉积相分布特征进行精细的识别和研究,该方法在库车坳陷库车组沉积相识别及分布研究中取得了良好的应用效果,解决了井间相带变化和地震相特征不明显带来的研究困难,对研究沉积相带分布和沉积相演化等基础石油地质研究具有重大的意义.

Application of 3D Magnetotelluric in Lithologic Identification ofthe Kuqa Formation in Kuqa Depression

In order to make up for the shortcomings of traditional recognition and research methods, such as the field outcrop, logging and earthquake and so on, 3D Magnetotelluric(MT) is used for the research of sedimentary facies. Through to 3D MT data pretreatment, such as de noising, editing and smothing, static shift correction and so on, and 3D inversion treatment, it is more accurate to reflect the resistivity of sediments from study area. Based on the observation of field outcrop and well logging interpretation, the resistivity value range of different rocks of the Kuqa Fomation is determined, which is calibrated by cores or cuttings. And then stratigraphic framework is established by corrected 3D MT profile congruent to seismic profile. Finally sedimentary facies in the period of Kuqa Formation are recognized and researched finely in stratigraphic framework. The method has obtained favorable application effects in the recognition and research of spatial distribution characteristic of sedimentary facies in the period of Kuqa Formation in the Kuqa Depression. What is more, the problems of sedimentary facies belt changed among wells and unconspicuous characteristics of seismic facies are solved, which is significant to research base oil geological such as distribution of sedimentary facies, sedimentary evolution and so on.