Application of multi-scale refraction tomography based on statistics of special geological bodies in Bohai Bay

Le résumé fourni par la source

Summary There are obvious velocity anomalies in shallow exploration in many structural areas of Bohai Bay, which directly affect the imaging accuracy of seismic data and the reliability of subsequent structural interpretation. Due to the influence of shallow gas cloud area, lateral velocity anomaly and other factors, there are low accuracy of shallow velocity model and poor consistency with the structure in these structural areas. Refraction tomography is a good method to model the shallow subsurface velocity field using the first arrival travel time information of seismic data. The conventional tomography method divides the velocity model into a single size grid, which is difficult to adapt to all shapes of velocity anomalies, and the inversion results are affected by the seismic ray path. In this paper, we proposed a muti-scale refraction tomography method based on statistics of Special geological bodies, which divides the multi-scale sub models by counting the size of special geological bodies in the block, and then superposition the sub models with different weight factors to obtain the final velocity modeling results. The result of numerical experiments and real seismic data demonstrate that our proposed method can build the shallow velocity field of underground accurately.

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