| China's western piedmont tectonic belt has excellent reservoir-forming conditions,high potential for oil and gas exploration,and seismic exploration technology in complex mountainous areas is the bottleneck of oil and gas exploration in complex piedmont tectonic belt.The difficulty of seismic data processing in piedmont seismic exploration mainly comes from the low signal-to-noise ratio and static correction problem of seismic data caused by complex mountain surface conditions.Based on the analysis of the limitation of conventional seismic data processing,this paper analyzes the main factors that affect the seismic imaging in complex mountainous areas,and studies the following key technologies.Microlog-constrained tomography static correction technology,Multi-domain noise suppression technology,DWT shallow velocity modeling and OVT domain sector azimuth grid tomography deep velocity modeling.The above key technologies have been applied in Tubei4 and have gained the following understanding:(1)Any single conventional seismic processing method can't solve the problem of complex mountain seismic imaging.The common idea of complex mountain seismic imaging is to analyze the various methods synthetically and then obtain the optimal combination.(2)The idea of solving complex mountain static correction is to solve the primary static correction with the microlog constrained tomography static correction technology and the residual static correction with multiple iterations.(3)Using the multi-domain coherent noise suppression technique to suppress the coherent noise,the OVT domain random noise attenuation technique suppresses the random noise,which can suppress the noise in the complicated mountain area.(4)Prestack depth migration is the necessary means to solve the complex mountain image,and the accuracy of the depth-velocity model directly affects the imaging quality.The PSDM migration has a good imaging result based on DWT shallow modeling and OVT domain sector azimuth grid tomography. |
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