Application Research On Multiples Attenuation Method For Deep Weak Reflection Data In Thick Desert Area

The seismic data of the thick desert area in the hinterland of the Junggar Basin is inferior in excitation and reception conditions.The interference of surface wave and refraction is serious.The multiple waves dominated by the Jurassic coal seam are extremely developed.The Jurassic coal seam also have a strong shielding effect on the downward transmission of energy.The deep Carboniferous targets in the background of various severe interference show the response characteristics of low frequency and weak reflection,which cannot be accurately described.The data analysis in recent years confirms that the multiple wave is an important factor hindering the deep exploration process.This paper takes the thick desert area in the hinterland of the Junggar Basin as the target.It systematically studies the multiple wave attenuation method around the deep weak reflection data of the Carboniferous,which is based on the Geo East processing software developed by the Eastern Geophysical Company.Then puts forward the overall idea of suppressing multiples for deep targets.Protecting low frequency information before suppressing multiples and the surface-consistent deconvolution method with a long operator and a big prediction step show the importance for the processing of the deep weak reflection data.The method of limitedoffset velocity analysis and the method of making velocity spectrum by avoiding the velocity range of strong multiples energy play a key role under severe multiples interference conditions.Based on the above,the processing effects of the methods of beamforming filter,Radon transform,the common mid-point stacking and internal cutting are compared and analyzed in this paper.The methods of suppressing multiples studied in this paper have achieved a breakthrough imaging effect in the 2D data processing of the Carboniferous in the hinterland of the Junggar Basin.