【摘要】 目前的水平集磁性目标体边界反演算法仅使用两个水平集,实际勘探存在多个具有不同磁化率的磁性地质体,需要进行多个水平集的反演,因而提出一种新的多重水平集反演算法,实现了对具有不同磁化率的多个磁性目标体位置和几何形状的反演。首先利用多重水平集原理建立多个水平集的反演目标函数;然后采用任意四面体单元磁法解析解进行高精度正演计算,并基于加权基本无振荡格式(WENO)对水平集函数进行更新并重新初始化,保证了反演的可靠度;最后通过不同数目水平集的理论模型验证该算法的有效性。测试结果表明:多重水平集反演具有很强的灵活性,可以自动合并、分离模型中的区域,改变模型的拓扑结构,不需要手动重新参数化,且反演精度高,反演的磁异常体边界与模型吻合很好。更多还原

【Abstract】 Present algorithms for inverting the boundaries of magnetic targets use only two level sets.There are usually multiple magnetic geological bodies with different susceptibility in actual exploration.This paper proposes a new multiple levelset inversion algorithm for 3D inverting the position and geometry of magnetic targets with known susceptibility.First,based on the principle of multiple level sets,an objective function based on a multiple level sets function is established.Then,during the inversion process,an arbitrary tetrahedron element magnetic analytical solution algorithm is used for high-precision forward calculation,and the physical property mapping between forward and inverse grids is used to realize the independent operation of the forward grids and the inverse grids.The weighted essentially non-oscillatory scheme(WENO)is introduced to update and reinitialize the level set function,thereby improving the reliability and efficiency of the inversion.Finally,the effectiveness of the algorithm is verified by theoretical models with various numbers of level sets.The results show that the inversion based on the multiple level-set method has strong flexibility,and can automatically merge and separate regions in the model,thereby changing the model’s topology with no need to manually reparameterize it.The accuracy of the inversion results is improved,and the boundary of the anomalous body obtained from the inversion accords well with the true boundary.更多还原