Method and apparatus for processing seismic data

A method for determining properties of geological strata below a surface, comprising:

• propagating seismic waves through the surface;
• recording reflection or refraction waves returned to the surface from a location below the surface at a plurality of locations, wherein the reflection or refraction waves comprise a seismic trace gather;
• stacking seismic trace gathers in a predetermined range among S seismic trace gathers after a Normal Move Out (NMO) correction processing to obtain a model trace, S being an integer;
• calculating a correlation coefficient of each seismic trace gather with the model trace, and selecting a K-th seismic trace gather with a maximum correlation coefficient;
• calculating an optimum point of each seismic trace gather from the K-th seismic trace gather to two sides orderly and by:
• sliding a time window in a predetermined time range, calculating a correlation coefficient of a (K−1)-th seismic trace gather with the K-th seismic trace gather, selecting the time window as an optimal point when the correlation coefficient is the maximum, and taking a time shifting amount corresponding to the optimal point as a residual NMO correction amount of the (K−1)-th seismic trace gather, wherein K>1 and K is an integer;
• sliding the time window in the predetermined time range, calculating a correlation coefficient of an M-th seismic trace gather with an (M+1) seismic trace gather, selecting the time window as an optimal point when the correlation coefficient is the maximum, and taking a time shifting amount corresponding to the optimal point as a residual NMO correction amount of the M-th seismic trace gather, wherein K−2≥M≥1 and M is an integer;
• sliding the time window in the predetermined time range, calculating a correlation coefficient of a (K+1)-th seismic trace gather with the K-th seismic trace gather, selecting the time window as an optimal point when the correlation coefficient is the maximum, and taking a time shifting amount corresponding to the optimal point as a residual NMO correction amount of the (K+1)-th seismic trace gather;
• and
• sliding the time window in the predetermined time range, calculating a correlation coefficient of an (N+1)-th seismic trace gather with an N-th seismic trace gather, selecting the time window as an optimum point when the correlation coefficient is the maximum, and taking a time shifting amount corresponding to the optimum point as a residual NMO correction amount of the (N+1)-th seismic trace gather, wherein S−1≥N≥K−1 and N is an integer, and the time shifting amount corresponding to the optimum point is a difference value between seismic reflection time of a seismic trace gather in the time window and seismic reflection time of a seismic trace gather with an offset of 0;
• performing a residual NMO correction of the seismic trace gathers according to the optimum points to create corrected seismic trace gathers;
• and
• determining depth, lithology, or fluid properties of the geological strata below the surface with the corrected seismic trace gathers.