远探测反射波声波测井方法实验研究进展

Progress of Lab Study on Remote Exploration Acoustic Reflection Logging Methods

在井下发射低频声波信号,按地震勘探工作方式接收反射波已经从理论和实际测井资料解释中得到确认.介绍了用大幅度(4000V)的窄脉冲激发声学探头,得到频率接近10 kHz的、可用于远探测反射波声波测井的低频声波信号的实验过程.为接收低频反射波信号,应该选择谐振频率较低的接收探头.在模拟井中按上述思路组装的声系可以测量记录到距离井壁约7～10 m处声学界面的反射波信号.实验结果可作为远探测反射波声波测井声系设计的依据.

It has been confirmed in theoretical study an d practical logging data interpretation that reflection wave can be obtained fro m seismic exploration working pattern and emitting low frequency acoustic signal in borehole. In this article, it is proved by experiments that, low frequenc y acoustic signal whose frequency is about 10 kHz can be obtained from narrow pu lse with huge amplitude (4 000 V) to stimulate the transmitter, and this kind of signal can be used in remote exploration acoustic reflection well logging. To receive such low frequency signals, receivers with low resonance frequency s hould be chosen. In simulation wells, acoustic sonde designed according to thi s idea could detect and record reflection signal from interface 7~10 m away from borehole surface. The experimental results of this article could be the basis for designing the remote exploration acoustic reflection logging sonde.