基于二阶导数的磁源边界与顶部深度快速反演  

Fast inversion of magnetic source boundary and top depth via second order derivative

作　　者：张恒磊[1,2] 胡祥云[1] 刘天佑[1,2] 

机构地区：[1]中国地质大学(武汉)地球物理与空间信息学院,武汉430074 [2]中国地质大学(武汉)构造与油气资源教育部重点实验室,武汉430074

出　　处：《地球物理学报》2012年第11期3839-3847,共9页Chinese Journal of Geophysics

基　　金：中国博士后面上基金(2011M501257);全国危机矿山接替资源找矿项目(200799084);中央高校基本科研业务费专项资金资助项目联合资助

摘　　要：为实现磁异常反演,首先提出了磁异常非参数快速反演的概念,即无需提供先验信息.在Nabighian提出的磁场通用梯度公式的基础上,推导实现了基于磁异常垂向二阶导数的非参数快速反演(V2D_depth).它不仅可以获取场源的边界信息,同时可以反演场源的埋深.通过与Tilt_depth方法对比,本文方法计算的场源边界更清晰,反演的深度也更接近真实深度,同时较大程度上克服了Tilt_depth方法受叠加异常的影响.理论模型验证了方法的有效性,并通过准噶尔盆地某区块磁异常数据的处理,提取了受强大的区域背景场掩盖的石炭系火成岩产生的弱异常,突出了构造分区、断裂分布等信息,获取了火成岩的位置及埋深参数,为该区的火成岩油气藏勘探提供了有效的处理途径.We proposed a new inversion concept called non-parametric fast inversion via derivatives of magnetic anomalies. Based on the general gradient expression of the magnetic field published by Nabighian, we got the non-parametric fast inversion via vertical second derivative （V2D_depth）. It can not only detect the source boundary, but also the depth of the source. Comparison with the Tilt_depth approach indicates that this method can obtain a clearer field source boundary and a more realistic depth, while it also overcomes the interference from superimposed anomaly in the Tilt_depth approach. The numerical experiment shows that the method is effective. We applied the method on processing magnetic data located at Junggar Basin. It picked up weak anomaly produced by Carboniferous igneous rocks which was covered by strong regional anomaly. This can highlight the tectonic division, fracture distribution etc, and can get the location and depth parameters of igneous rocks. So it provides a new approach for the oil-gas exploration related to igneous rocks.

关 键 词：磁法勘探 边界分析 非参数反演 准噶尔盆地 

分 类 号：P631[天文地球—地质矿产勘探]