正交偶极声波测井换能器有限元分析

Analyses of cross-dipole acoustic well logging transducers based on finite element method

三叠片型换能器是正交偶极声波测井仪器的重要组成部分。换能器的性能直接影响声波测井数据的质量。本文在前人工作基础上,针对三叠片型声波测井发射换能器长度方向的一阶弯曲振动工作模式,利用有限元方法,模拟了换能器结构尺寸和边界条件变化对换能器性能的影响。结果显示,结构尺寸和边界条件对换能器的谐振频率和电导值均有不同程度的影响。参考数值模拟结果,选取合适的结构尺寸参数和边界固定方式,可以调整和选择正交偶极声波测井仪器发射换能器工作频率和最大发射效率。本文研究结果对三叠片型换能器的优化设计有较好的指导意义。

Sandwich transducers are important parts of a cross-dipole acoustic logging tool. The performance of the transducers directly affects the quality of acoustic logging data. Aimed at the first longitudinal bending vibration mode of a sandwich transducer, the influence of structure sizes and boundary conditions of the transducer on the performance parameters was simulated numerically using finite element method. The results show that structure sizes and boundary conditions affect the resonance frequency and conductance differently. According to the numerical simulation, the proper working frequencies and highly efficient radiation performance which satisfy the cross dipole logging can be obtained by choosing adequate structure sizes and boundary conditions. Numerical simulation resuhs serve as a good guidance on the optimization design for the sandwich transducers.