多极子阵列声波测井数据的纵横波慢度联合反演方法

Joint inversion for compressional and shear wave slowness using multipole acoustic array logging data

多极子阵列声波测井仪器采集的单极和偶极数据受到地层、井孔、仪器测量系统的影响.在处理实际声波测井数据时,必须考虑多极子模式波的频散效应,以及测井仪器在其中的影响.根据仪器等效理论和相位匹配方法,本文提出了一种从多极子阵列声波测井数据中同时获得纵、横波慢度的联合反演方法.这种方法的关键在于利用相同仪器-地层模型计算多极子模式波频散曲线,以此来匹配频域内纵波与横波数据的相位.相对于将泄漏纵波和弯曲波频散效应分开处理的其他方法,该方法不仅可以减少纵横波速度反演的不确定性,而且还避免了从声波数据中提取频散数据的繁琐过程.通过理论分析和现场数据处理证明了本文联合反演方法的准确性和有效性.

Monopole and dipole waves acquired by the multipole acoustic array logging tools are jointly affected by formation and borehole-tool system.When processing real acoustic logging data,the dispersion effect of multipole acoustic waves must be considered and the influence of logging tools cannot be neglected.Based on the equivalent tool theory and phase matching method,we develop a joint inversion method to simultaneously calculate compressional (P) and shear (S) wave slowness using the multipole logging data.The key in this inversion is using the multipole wave phase dispersion curves computed from the same tool-formation model to match the phase of the P- and S-wave data in the frequency domain.Compared with other individual dispersion processing methods for leaky-P or flexural wave data,this inversion method can not only reduce the uncertainties of P- and S-wave velocities estimation,but also avoid tedious dispersion extraction from acoustic logging data.Theoretical analyses and field data processing results demonstrate the validity and effectiveness of this new method.