将各向异性地层模拟为横向各向同性双相介质 ,使其对称主轴与井孔中心轴线相垂直 .本文针对井孔模型下的多极源声波测井问题提出了一种解析的摄动方法 .将各向异性双相介质看作是由对应的各向同性双相介质加上摄动部分而组成 ,并引入 5个关于弹性模量偏离各向同性时的摄动量 ,对对称主轴与井轴垂直的各向异性双相介质的多极源声波测井问题进行了系统的理论研究和分析 ,严格求解了井孔内外的零级和一级近似声波场 .发现在n级多极源激发下 ,井孔中不仅出现n级多极声场 ,而且还能激发出与各向同性地层时不相同的高于和低于n级的多极声波场 The anisotropic formation is modeled as a transversely isotropic two-phase medium with its symmetry axis perpendicular to the central axis of the wellbore.In this paper, an analytical perturbation method is proposed for multi-polar sonic logging in a wellbore model The anisotropic two-phase medium is considered as consisting of the corresponding isotropic two-phase medium plus the perturbation and introduces five perturbations on the deviation of the elastic modulus from the isotropy, Axis perpendicular anisotropic dual-phase acoustic multi-polar sonic logging is systematically studied and analyzed, and the zero-order and first-order approximate acoustic fields inside and outside the wellbore are solved strictly. , Not only the n-level multi-polar sound field appears in the borehole, but also the multi-polar sound field above and below n-level that is not the same as that in the isotropic formation