地下铁质管线磁偶极子构造法正演单元划分策略  

Voxel partitioning strategy of magnetic dipole reconstruction for underground ferrous pipeline magnetic anomaly

作　　者：刘得军[1] 郭智勇[1,2] 朱慧慧[1] 潘琦[1] 艾清慧[1] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]西南石油大学机电工程学院,成都610500

出　　处：《地球物理学进展》2016年第6期2756-2761,共6页Progress in Geophysics

基　　金：国家自然科学基金资助项目(41374151)资助

摘　　要：地下铁质管线经过地球磁场的磁化产生磁异常,对铁管磁异常进行数值分析可以帮助探测地下铁管的位置.为了在保证磁偶极子构造法地下铁质管线探测面磁异常正演准确性的前提下,尽量减少正演计算时间,在相对球坐标系中建立了管道单元划分策略分析模型,分析了测点空间位置对不同单元划分条件下磁异常计算差异的影响.研究结果表明:不同单元划分计算测点磁异常差异仅与距径比有关,相对误差与单元磁化率和外磁场特征无关;随着距径比增大,磁异常计算差异逐渐减小.在6.5倍距径比范围内,使用分块单元划分建立地下管线磁异常计算模型,在6.5倍距径比范围外,使用分节单元划分建立地下管线磁异常计算模型,不仅保证了管道磁异常正演计算的准确性,而且能够提高管道磁异常计算速率.After going through the magnetization of earth ＇s magnetic field,the underground ferromagnetic pipeline will produce magnetic anomaly. The numerical analysis approach can be used to detect the location of underground ferromagnetic pipeline. Based on total magnetic anomaly（ TMA） forward of underground ferromagnetic pipeline by magnetic dipole reconstruction, this paper build a pipeline element division strategy analysis model in relative spherical coordinates to not only minimize the calculation time of forward,but also study the effect of spatial position of measure point on calculated TMA error by different element divisions. The results indicate that the calculated TMA error by different element divisions on measure point is only related by distance to diameter ratio,but not determined by magnetic susceptibility of pipeline material and characteristics of external magnetic field. When the ratio of distance to diameter is increased, the calculated TMA error will be decreased. When the ratio of distance to diameter is less than 6. 5 times,the block element division can be used to build TMA forward model of underground ferromagnetic pipeline. If the ratio of distance to diameter is more than 6. 5 times,the section element division can be used to build TMA forward model of underground ferromagnetic pipeline. In this way, we can not only ensure the veracity of pipeline TMA forward calculation,but also improve the computation rate of pipeline TMA forward calculation.

关 键 词：铁质管线 管线探测 磁偶极子构造法 单元划分策略 相对球坐标系 

分 类 号：P631[天文地球—地质矿产勘探]