High temperature and high voltage excitation test of dipole transducers based on bending vibration

The laminated dipole emission transducer with bending vibration for acoustic logging serves as a core component of conventional dipole logging tools. Its radiation performance and stability under high-temperature and high-pressure conditions directly determine the quality of acoustic logging data. To meet the requirements of ultra-deep well exploration, multi-cycle high-temperature (230 ℃) oil bath testing, combined with high-voltage (1 800 V) excitation, was conducted to monitor the acoustic impedance characteristics of the transducer assembly in real time. Results indicate that transducers fabricated with commercial high-temperature piezoelectric ceramic materials and stringent manufacturing processes exhibit no debonding or fracture throughout four rounds of extreme testing. The resonant frequency shows a low-frequency shift (<5%), while the maximum electrical conductance decreases significantly (85%–95% reduction in X/Y directions). Static capacitance increases reversibly with temperature, and the mechanical quality factor remains stable (<10% fluctuation). Parameter variations are consistent in the X andY directions, with differences within acceptable engineering tolerances. This study provides critical data support for the development of high-temperature acoustic logging tools, dipole remote detection systems, and push-type long-duration operation equipment, while also verifying the reliability limits of materials and processes under extreme 230 ℃ conditions.

用于声波测井（acoustic logging）的弯曲振动型层叠偶极发射换能器（dipole emission transducer）是传统偶极测井仪的核心组成部件，其在高温高压环境下的辐射性能与稳定性直接决定声波测井数据的质量优劣。为满足超深井勘探需求，本次研究开展了多循环高温（230℃）油浴试验（oil bath testing）并配合1800V高压激励，实时监测换能器组件的声阻抗特性。试验结果表明，采用商用高温压电陶瓷（piezoelectric ceramic）材料与严苛制造工艺制备的换能器，在四轮极端测试中未出现脱粘或断裂现象；谐振频率（resonant frequency）出现小幅低频偏移（偏移量小于5%），而最大电导（electrical conductance）显著下降（X/Y方向降幅达85%~95%）；静态电容（static capacitance）随温度呈可逆性增长，机械品质因数（mechanical quality factor）则保持稳定（波动幅度小于10%）。各参数在X、Y方向的变化趋势一致，差值均处于可接受的工程公差（engineering tolerances）范围内。本研究为高温声波测井仪、偶极远程探测系统以及推靠式长时作业装备的研发提供了关键数据支撑，同时验证了材料与工艺在230℃极端环境下的可靠性极限。