一种随钻四极子复合发射换能器的设计

设计了一种基于金属基片结构的随钻四极子复合发射换能器。采用有限元法数值模拟了换能器的频域及时域声学响应,考察了钻铤结构及声源激励脉冲宽度对其声学特性的影响,实际封装制作了发射换能器并进行了消声水池实验测试。测试结果表明,该发射换能器的谐振频率、发射电压级及水平指向性与数值模拟结果吻合较好。该换能器在频率4.7 kHz附近存在一阶弯曲振动模态,其发射电压级可达126.2 dB,具备低频、大功率的辐射特点,可满足随钻四极子声波测井需求。

Design of a LWD Quadrupole Composite Transmitting Transducer

A logging-while-drilling(LWD) quadrupole composite transmitting transducer based on metal substrate structure is designed in this paper. The frequency domain and time domain acoustic responses of transducer are numerically simulated by the finite element method. The effects of the collar structure and excitation pulse width on its acoustic characteristics are investigated. A practical transmitting transducer is fabricated and encapsulated for the experimental test in the anechoic water tank. The test results show that the resonant frequency, emission voltage level and horizontal directivity of the transmitting transducer are in good agreement with the numerical simulation results. The transducer has a first-order bending vibration mode near the frequency of 4.7 kHz, and its emission voltage level can reach 126.2 dB. Therefore, it has the characteristics of low frequency and high power radiation, and can meet the requirements of the quadrupole acoustic logging-while-drilling.