随钻声波测井圆弧状压电阵子的有限元分析  

The finite element analysis of arcuate shaped piezoelectric vibrator used in LWD acoustic logging

作　　者：孙志峰 唐晓明[1] 苏远大 陈洪海[2] 仇傲[2] 李杰[2] SUN Zhifeng;TANG Xiaoming;SU Yuanda;CHEN Honghai;QIU Ao;LI Jie(School of Geosciences,China University of Petroleum,Qingdao 266580,China;China Oilfield Services Limited,Beijing 101149,China)

机构地区：[1]1中国石油大学(华东)地球科学与技术学院,青岛266580 [2]中海油田服务股份有限公司,北京101149

出　　处：《应用声学》2019年第5期807-814,共8页Journal of Applied Acoustics

基　　金：国家科技重大专项(2017ZX05019002-006)

摘　　要：圆弧状压电阵子是随钻声波测井仪发射换能器的核心部件。利用有限元法对圆弧状压电阵子进行了设计分析,结果表明20kHz以下频率范围内主要存在弯曲振动模态及径向振动模态,且径向振动模态能够满足随钻声波单极测量模式的工作频率要求。针对径向振动模态,数值模拟了几何尺寸对压电阵子声学性能参数的影响。圆弧状压电阵子的谐振频率随着陶瓷片厚度的增大而升高;随着陶瓷片高度、半径及张开角的增大而降低。圆弧状压电阵子的最大发射电压级幅值随着陶瓷片厚度、张开角的增大而降低;随着半径的增大而升高;随着陶瓷片高度的增大,最大发射电压级幅值先升高后逐渐降低。以外径为6.75in的钻铤为例,最优化设计了圆弧状压电阵子的尺寸,使其满足钻铤模式波隔声阻带中心频率的要求,同时保证了压电阵子具有最大发射电压级。数值模拟结果可以对随钻声波测井仪发射换能器设计起到良好的指导作用。Arcuate shaped piezoelectric vibrator is core component of the logging while drilling (LWD) acoustic transducer. Arcuate shaped piezoelectric vibrator is designed and analyzed applying a finite element method. The results show that there are mainly bending vibration mode and radial vibration mode in the frequency band below 20 kHz, and radial vibration mode meets operating frequency requirement for LWD monopole acoustic transducer. For the radial vibration mode, the influence of geometrical size of arcuate shaped piezoelectric vibrator on the performance parameters is also simulated numerically. The resonance frequency will rise as thickness of ceramic plate increases and reduce as height, radius and opening angle of ceramic plate increase. The maximum emission voltage level will reduce as thickness, opening angle of ceramic plate increase and rise as radius increases. When height of ceramic plate increases, maximum emission voltage level will increase first and then decrease gradually. Taking drill collar with outer diameter of 6.75 in as an example, the size of arcuate shaped piezoelectric vibrator is optimally designed to meet requirements of center frequency of collar’s stopband and maximum emission voltage level. The numerical simulation results play a good guiding role on the design of the transmitting transducer of LWD acoustic logging tool.

关 键 词：圆弧状压电阵子 谐振频率 频率响应 发射电压级 有限元 

分 类 号：P631.52[天文地球—地质矿产勘探]