任意密度分布复杂地质体重力异常快速三维正演方法  

Three-dimensional forward modeling method for gravity anomalies of complex geological bodies with arbitrary density distribution

作　　者：陈轻蕊 陈龙伟[2] 戴世坤[1] 张钱江[1] 欧阳芳[1] CHEN Qingrui CHEN Longwei DAI Shikun ZHANG Qianjiang OUYANG fang(School of Geosciences and Info -Physics, Central South University, Changsha 410083 , China College of Earth Sciences, Guilin University of Technology, Guilin 541006 ,China)

机构地区：[1]中南大学地球科学与信息物理学院,长沙410083 [2]桂林理工大学地球科学学院,桂林541006

出　　处：《物探化探计算技术》2017年第2期176-182,共7页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目(41404106)

摘　　要：解决任意密度分布复杂地质体重力异常三维正演快速、高精度计算问题,是实现重力三维反演、人机交互解释建模的关键。针对该问题,从积分方程出发,提出一种波数域重力异常三维正演方法,其关键环节包括三个方面:(1)将研究区域剖分成许多规则小棱柱体,每个小棱柱体密度值可以任意给定,以此刻画任意密度分布和起伏地形条件下的复杂地质体;(2)给出一种新的高精度均匀棱柱体重力异常二维波数域的计算公式,用于计算组合棱柱体模型的重力异常;(3)采用Gauss-FFT法将重力异常从波数域转换到空间域,保证计算效率的同时,有效克服了传统FFT法引起的边界效应问题。模型算例检验结果表明,该算法计算速度快、精度高,对于剖分为百万个棱柱体的模型,耗时只需几秒。Rapid three-dimensional （3D） forward modeling of gravity anomalies of complex geologic bodies with arbitrary density distribution plays an important role on 3D inversion of gravity and human-computer interaction modeling and interpre-tation. This paper proposes a wavenumber domain 3D forward modeling method. This new method has three key aspects： （1） prism based subdivision strategy. The research area is divided into many small regular prisms, density for each small prism can be given arbitrarily, in order to simulate complex geological body with arbitrary density distribution and undulating topography; （2） new wavenumber domain formula for computing gravity anomaly of combined prism model; （3 ） Gauss - FFT method. This paper uses Gauss -FFT method to transform the gravity anomaly from the wave number domain to the spatial domain. The Gauss - FFT method not only has high computational efficiency, but also suppresses the boundary effect and avoids the singular problem at zero wavenumber caused by the traditional FFT method. Numerical tests show that the proposed method is fast and accurate. It takes only a few seconds to calculate gravity anomaly for the combined 3D model with millions of prisms.

关 键 词：重力异常 三维正演 Gauss-FFT 积分方程 

分 类 号：P631.1[天文地球—地质矿产勘探]