The Extraction Of Dipole Array Reflected Acoustic Wave

The detection zone of the dipole S-wave logging technology reaches tens of meters,which lies between traditional logging and geophysical prospecting.It can effectively eliminate the blind spots and play an increasingly important role in the exploration and development of carbonate rocks and other formations.The reflected P-wave is much weaker than the reflected S-wave,so the reflected S-wave is used to describe stratigraphic structure.However,in soft formations,the attenuation of S-wave is higher than P-wave,and its propagation distance is significantly reduced compared to that in hard formations.The application of dipole reflected S-wave logging in soft formations is limited,while the reflected P-wave has become a feasible alternative.In this paper,the application of dipole array reflected acoustic P-wave in soft formation is studied,the radiation characteristics of the dipole sound source are analyzed and the formation model is established,and the problem of interference caused by the reflected acoustic wave on the artificial truncated surface is solved by using the perfect matching layer.After the signal is collected,the signal is processed by FK filtering,median filtering,and parameter estimation method respectively,and the reflected wave signal is obtained.Afterwards,the data processed by FK filtering and median filtering is processed by inclination filtering to obtain the dipole reflected P-wave.In addition,we also established a hard formation model and a soft formation model with no reflector to analyze the difference between the application effect of this process method in soft and hard formation and the difference between the real results and the theoretical results.The processing result shows that the data collected in the soft formation processed by FK filtering and median filtering can be used to obtain ideal reflected P-wave by the inclination filtering,which proves the feasibility of the extraction of dipole array reflected acoustic P-wave in the soft formation;The same processing is performed on the data collected in the hard formation,and the effect is relatively poor,indicating that the application of the dipole S-wave logging in the soft bottom layer is limited.Combining the above results,it shows the necessity and feasibility of applying the dipole array reflected acoustic P-wave logging to replace the dipole reflected S-wave logging in soft formations.