Research On Extraction Method Of Reflected Wave Based On Array Acoustic

With the deepening of oil and gas exploration,the requirements for exploration methods are increasing.Array acoustic reflection imaging logging is an exploration technology based on the gap between traditional acoustic logging and VSP crosshole seismic.This technology can be used to detect geological structures such as fractures,dip layer,karst caves and so on.The detection depth can be improved from centimeter-meter level of traditional acoustic logging to meter-tens meters level.Therefore,it can image areas that can not be recognized by traditional sonic logging and seismic,and improves the exploration system.In recent years,many new data processing methods for reflected wave imaging have been proposed at home and abroad,and new detection instruments have been designed,which lays a good foundation for further development of reflected wave imaging technology.In this paper,the numerical simulation of elastic wave staggered-grid finite difference method is studied.The complex frequency-shifted perfectly matched layer(CFS-PML)is used as absorbing boundary to reduce the influence of boundary reflected wave.The median filtering,wavelet transform,high resolution Radon transform and other methods of reflected wave extraction are studied,and numerical simulation data are used to verify the effects of various methods of reflected wave extraction.Finally,the shearlet transform is introduced to extract reflected wave,and compared with other methods of extracting reflected wave,which verifies the effect of shearlet transform in extracting reflected wave.In the field data processing of monopole,the effect of extracting reflected wave is not obvious enough,but the reflected wave signal is enhanced by applying the technology of stacking data across array.