A Study On High-precision Processing Technology Of Seismic Data

With the development of oil and gas exploration, the seismic prospectings give more and more emphasis on precise imaging of complex, small and deep structure. The overall objective of High-precision processing technology is to pursue high SNR, high resolution, high fidelity, so the ways of improving them should be deeply studied and lay a good foundation for the next accurate interpretation.In this thesis, the high-precision processing methods of3D seismic data is studied in detail. It is based on the3D seismic data in deep alley of Biyang depression.Considering the types and characteristics of the noises in the studying area, the3D cone filtering technology in f-kx-ky domain can not only suppress the surface waves, but also retain the low frequency effective wave; both the methods of correction of amplitude anomalies and spatial amplitude smoothing are applied to suppress the anomal amplitude disturbance; the technology of mono-frequency noise attenuation is used to suppress the50Hz industrical disturbance; the predictive deconvolution is used to eliminate the multiple waves.Using the methods of spherical spreading compensation and surface consistency amplitude compensation, not only eliminates the energy differences of the seismic waves in shallow, medium and deep formations, but also eliminates the energy differences between shots and traces caused by the inconsistencies of the surface shooting and receiving conditions. Hence, the amplitedes get equalized in both vertical and horizontal directions.Combining the advantages of predictive deconvolution and surface consistency deconvolution, the inconsistency problem caused by the changes of the surface shooting and receiving conditions of the wavelets in horizontal direction is removed, making the sub-wave shape and amplitude consistent in horizontal direction. At the same time, the seismic wavelet is compressed and the spectrum is broadened. The vertical resolution of seismic data is improved, while ensuring a reasonable signal-to-noise ratio.Based on having resolved the problem of long-wavelength static correction, the multiple iterations technology of the velocity analysis and surface consistency residual statics in different frequencies is applied to control the residual statics within a sample interval.On the premise of ensuring the quality of CMP gathers before migration, Kirchhoff prestack time migration is done in this paper. Using the stacking velocity as the initial RMS velocity, the velocity model is modified through prestack and velocity iterations. Ultimately, the CRP gathers is flattened and the common reflection point is stacked.