方位远探测声波测井仪接收声系实验研究

方位远探测声波测井仪接收声系中各通道接收换能器及相应采集电路的综合一致性极大地影响处理结果的精确度,必须测试并进行必要的校正。在实验室构建了接收声系测试系统,使用主频10 k Hz的单极子声源辐射声场,测量了阵列化声系中每个换能器单独正对单极声源时所有通道的采集波形,分析了波形的时域和频域特征,对声系站内、站间的各通道综合一致性进行了评价并给出接收通道一致性不好时的校正公式;对比了相控接收子阵与单个阵元的接收特性。实验结果表明,该声系各通道综合一致性较好,不需要校正;软件相控处理后,接收阵的能量比单个阵元强、指向性更好,有利于提高有用信号的信噪比和空间的探测分辨率。

Experimental research on receiver sonde of azimuthal remote acoustic reflection imaging logging tool

The comprehensive consistencies of the receiving transducers in all channels and their corresponding acquisition circuits in the receiver sonde of azimuthal remote acoustic reflection imaging logging tool can greatly affect the accuracy of processing result. So evaluation of comprehensive consistencies must be done and correction is needed when necessary. The testing system of receiver sonde was established in laboratory, and the monopole source with the dominant frequency of 10 kHz was used to radiate the acoustic field. The receiving waveforms of all channels were tested in the array of the sonde when each transducer was directly facing the monopole source alone, and characteristic of the waveform in time domain and frequency domain was analyzed. We evaluated the comprehensive consistencies of all channels in and among the stations of the sonde and gave the correction formula for the receiving channels with bad consistency. Besides, we compared the receiving characteristics of the phased receiving subarray and single element. The experimental result showed that the comprehensive consistencies of all channels were satisfactory, so corrections were not needed. The energy and directivity of the subarray were better than single element after the phased processing, which would help improve the signal-to-noise ratio (SNR) and the resolution of detection space.