The Application Effect Of Near-surface High-precision Modeling (STP) And Quality Factor Value Q In The Sichuan Basin

As Sichuan Basin is mainly composed of mountains and hills,the surface geological condition in basin is complex that the variation in vertical and horizontal direction is great in the low-velocity layer.The variation of the velocity and thickness of the low-velocity and the inregularity of the surface produced the inaccuracy of statics correction and the attenuating of the seismic frecuency.To approach the accurate statics correction values and compensate the attenuated seismic profiles with the Q values exacted in the spot area is the key to solve those problems.The STP(short for Surface Tomography Prospect)use smaller trace interval and offset than any other statics correction methods could sampling adequately in area where the surface geological condition variation is great.This will help to build the velocity model more precisely and the accuracy of statics correction values will be raised.On the other hand,to apply the Q values acquired by formula fitting and stratified extracting to compensate the attenuated seismic profiles will help to enhance the shoots' frequency spectrum and energy.In order to seek the effect and the best fit situation of the application of STP method and Q values in Sichuan Basin,this thesis intend to contrast the profiles that presant three typical kinds of surface geological conditions in Sichuan Basin that prospected by diffrerent four kinds of statics correction methods(refraction correction,microlog static correction,tomographic correction and STP).Meanwhile with the Q values applied to the attenuated profiles,the frequency spectrum and energy enhanced obviously.This thesis finally achieve the goal to find the best fit situation to apply the STP method and enhance the quality of seismic profiles by those works done.