The Landfill Lining Leaks Position Detection Of Repairment Based On Seismic While Drilling

The vibration that are emitted from drill-bit used as seismic wave source in seismic while drilling(SWD),with the features of real-time, no risks of going down to the well, and high efficiency. Based on the characteristics of seismic while drilling, combined with the special layered structure of the landfill, the seismic drilling technology was used to determine the landfill gravel layer. The characteristics of seismic wave fields and the time-frequency characteristics of vibration signals in different media were investigated, the drill bit signal influenced by the drill string was analyzed and the drill bit signal was recovered based on the principle of deconvolution, wavelet transform domain correlation algorithm was put forward to detect the sub-wave delay information in case of low signal to noise ratio,and the cross-correlation-wavelet transform method was presented to pick up first break in seismic while drilling with the delay information and the characteristic frequency information,which provided a basis for the landfill near-surface velocity inversion. The numerical simulation and field experiments show that the algorithm can reach the desired effect and the research results of this paper has a certain practical significance on the gravel layer quick determining.