| Popis: |
We present a new redatuming technique based on the virtual surface, Rayleigh integral and phaseshift method. Combining the redatuming technique with the pre-stack time migration results in a pre-stack time migration scheme and workflow which can be applied to the dataset acquired at the irregular surface. The resultant scheme can correctly model seismic wave propagation in the complex near the surface, thus avoiding the errors with respect to the static correction when the high speed media expose on the surface. Moreover, we give a method to determine the reasonable velocity of virtual medium. No prescribed near surface velocity model, which is key for the conventional redatuming technique, is needed. Two synthetic datasets, which are respectively related to the models with presence and absence of the low speed media on the surface, are used to verify the proposed schemes. |
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