重力异常变密度界面深度反演方法对比

Comparison of Inversion Methods of Gravity Anomaly with Variable Density Interface Depth

界面深度反演是重力异常定量地质解释的常用方法,学者们针对界面反演问题提出了多种经典算法。以密度随深度变化的直立长方体为基本单元搭建了合成模型,在此基础之上对比了经典的Bott法与非线性反演方法,分析了它们各自的特点和适用环境。模型试验表明:1)Bott法所需要的迭代次数比非线性反演多;2)界面节点个数较少时,非线性反演与Bott法所需计算时间接近,界面节点较多时,Eott法所需计算时间明显小于非线性反演;3)二者反演效果接近。在实际勘探中,需要根据不同客观条件选择具体的界面深度反演方法。

Interface depth inversion is a common method for quantitative geological interpretation of gravity anomalies.Scholars have proposed a variety of classical algorithms for interface inversion problems.In this paper,we use a synthetic model that is constructed based on the vertical cuboid with density varing with depth.On the basis of this,the Eott's method and nonlinear inversion met hod are compared,and their respective characteristics and application environments are analyzed.The model test shows that:1)the Eott's method requires more iterations than the nonlinear inversion;2)when the number of interface nodes is small,the nonlinear inversion is close to the calculation time required by the Bott's method,and the Bott's method is more when there are many interface nodes.The required calculation time is significantly smaller than the nonlinear inversion;3)the inversion effects are close.In actual exploration,specific interface depth inversion methods need to be selected according to different objective conditions.