A Practical Near-surface Construction Technique for Overthrust Data with Simulated Annealing Algorithm

The accuracy of near-surface velocity construction always plays an important role when dealing with overthrust data. Under the assumption of equivalent layered medium, we combine micro well-log information and first-arrival of surface seismic survey as prior information to estimate near-surface velocity structure based on Monte Carlo optimization scheme. The simulated annealing algorithm is taken to search the global optimum. Compared with conventional least-square (LS) based first arrival tomography, a clearer base of low-velocity-layer can be delineated thus it will surely be helpful to either wave-equation datuming or statics correction. The numerical tests on two synthetic and one real data examples demonstrated the effectiveness of this scheme.