Study On The Data Processing Of Reflection Seismic Exploration Of Cenozoic Era Volcanic Rock Covered Area In Songjiang River,Jilin Province

The zones where volcanic rocks is strong can form a variety of metal,non-metallic minerals, in exploration of this kind of area, seismic exploration plays its inherent advantages. The main advantages are that the exploration scope is big, the exploration depth is large, and the information obtained in the space has better continuity.However,volcanic rock covered area,due to the volcanic eruption, metamorphism,intrusion, and tectonic structure development, lithology change,complex surface conditions,determine the existence of volcanic rock seismic exploration difficulties.First, surface features, there is large height difference in part of this area, coupled with humus and marsh in the shallow depth, height inconsistency of surface excitation and receiving condition, lead to more prominent static correction problem.Secondly, different surface conditions and the shooting parameter, coupled with complex medium-deep fault and complex fracture system derived from it bring in a large change in seismic wave characteristics(frequency and apparent velocity, etc),some interference, such as surface wave and multiple refraction and environmental noise,is difficult to distinguish from effective wave,causing greater difficulties to the work of denoising.At the same time, the complexity of the surface feature makes adjacent shot gath and each trace in shot gath and received signals at different times significant difference in terms of energy, frequency, phase, etc,also cause large difference between seismic wavelet.After earth filtering,seismic wavelet change its original phase feature,moreover,its frequency is dropped,reducing stratigraphic resolution.Therefore, there are many problems in seismic exploration of volcanic rock covered area.This paper analyzes the characteristics of seismic data and its processing difficulty. Corresponding seismic processing methods are applied to different types of processing problems.In static correction,the accuracy of the velocity model and the correction effect of tomographic statics are tested.In denoising, compound denoising technique is used and its effect on the suppression of multiple interference wave is tested.In the aspect of deconvolution,surface consistent deconvolution method is applied,to verify its effect of compressing the wavelet and eliminating the impact of surface factors on the amplitude and wavelet,as well as improving resolution.Through application of above processing methods,the suitable processing method of the seismic data is obtained.It is indicated that the accurate shallow layer velocity model can be obtained by tomographic statics correction,aslo getting a good static correction effect.Compound denoising technique can be used to suppress various kinds of interference wave.Surface consistent deconvolution can be used to compressing the wavelet and eliminating the impact of surface factors on the amplitude and wavelet,as well as improving resolution.Finally, by comparing the seismic single shot with the seismic section., the reliability of the results is verified.It has guiding significance for the processing of seismic data in the area of volcanic rock covered area.