可控敲击声源在干井声波测井中的可行性研究

Feasibility Study on Controllable Knocking Sound Source of Acoustic Logging in Dry Well

在干井条件下,常规声波测井仪器的声源由于井中流体缺失无法应用。探讨采用电磁冲击锤敲击井壁产生声波信号进行测井的可行性,设计电磁锤激励控制电路和发射、接收分离试验系统,并在实验井中进行测试分析。实验结果表明,电磁锤声源性能受激励电压与激励脉冲宽度控制,声波信号的到时随激励电压的增大而减小,应用时可根据实际需要对激励参数进行选择,证实该系统可有效测量地层声速信息。在测量理论和接收波形分析等方面开展深入系统研究,有望开发出干井中的声波探测技术,在煤矿勘探和开采中广泛应用。

Under dry well conditions,the acoustic source of conventional acoustic logging instruments cannot be widely used due to the lack of fluid in the well.This paper discusses the feasibility of generate acoustic signals for logging by using electromagnetic impact hammer to strike the borehole wall.Designed electromagnetic hammer excitation control circuit,transmission and reception separation test system,is tested in the experimental well.The results show that the acoustic source performance of the electromagnetic hammer is controlled by the excitation voltage and the excitation pulse width,and the arrival time of the acoustic wave signal decreases with the increase of the excitation voltage.The excitation parameters can be selected according to the actual needs in application,which confirms that the system can effectively measure the formation sound velocity information.It is expected to develop acoustic wave detection technology in dry well conditions by carrying out in-depth systematic research on measurement theory and receiving waveform analysis,which can be widely used in coal mining exploration and production.