用于随钻声波测井的圆弧片状压电振子

Arc Plate-type Piezoelectric Vibrator Used in Acoustic Logging-while-drilling

提出了应用于随钻声波测井的圆弧片状压电振子,并以自制的4个压电振子进行了性能评价实验研究。压电振子是由径向极化且内外表面镀有银层的圆弧形压电陶瓷片构成,采用内外包覆环氧树脂进行封装。对压电振子的性能评价测试结果的分析表明,一定频带内压电振子存在多种振动模态,其中以径向振动为主的耦合振动模式能够满足随钻声波测井工作频率和大功率发射的要求。压电振子辐射的声束主要以一定的角宽向某一方位方向传播,具有方位指向特性。组成复合换能器的4个压电振子的性能特性一致性良好,可应用于随钻声波测井实现单极子、偶极子和四极子辐射器。

A kind of arc plate-type piezoelectric vibrator is presented which can be used in acoustic logging-while-drilling(LWD). The piezoelectric vibrator is constituted by a circular arc piezoelectric ceramic with radial polarization and inner and outer silvering surfaces,and encapsulated with internal and external epoxy coat. To investigate its performance characteristics,4piezoelectric vibrators are fabricated to conduct performance evaluation tests.Test results show that the piezoelectric vibrator has abundant vibration modes,of which the coupled vibration mode based more on radial vibration is able to satisfy the requirements of the operating frequency and high-power transmission for acoustic LWD.The piezoelectric vibrator has an azimuthal directionality,enabling to generate the directional radiation acoustic beam with certain lobe width.The performances of 4 piezoelectric vibrators constituting the complex transducer are reasonably consistent,which can be combined to form LWD acoustic monopole,dipole and quadrupole transmitters.