Application Research On The Static Correction Methods Under Complex Near-surface Conditions

The heterogeneous variations of thickness and velocity of low deceleration zone in near-surface layers in seismic exploration cause the non-uniform delay of seismic wave travel time. Therefore,the observed reflection travel times are distorted, greatly affecting the imaging and structural geometry in stacked sections. All the effects need to be eliminated by static correction methods. So, it is key and necessary to obtain the correct static correction values for the seismic processing under complex near-surface conditions. If the serious static problems are not solved very well, the false or low signal-to-noise ratio seismic images in seismic profiles will result in the difficult structural interpretations, and even wrong geological understanding. So, how to solve the static problems is the primary task for the seismic data processing under complex near-surface conditions.The static methods, such as extended generalized reciprocal method static correction(EGRM),two-dimension interactive iteration static correction, refraction tomographic static correction and dune static correction are analyzed and discussed in this dissertation. Based on the detailed analysis of the geological features under complex near-surface conditions, the primary problems on static correction and the advantages and disadvantages of various static correction methods, different methods are presented to solve the static correction problems under mountain, desert and loess tableland, respectively. Long wavelength static correction method controlled by the unified calculation refraction static correction method, refraction tomographic static correction method and dune curve station correction method are optimal to solve the static correction problems in mountain, desert and loess tableland, respectively. Real seismic data processing showed obviously improved processing quality of seismic profiles, demonstrating the methods are feasible.