Abstract: Seismic exploration accuracy meets higher and higher requirements since the exploration targets in Dongpu Sag tend to be more subtle and complicated. For this, this paper puts forward a new method for acquiring horizon velocity based on joint inversion of stack velocity and migration velocity, improving the accuracy of velocity calculation. Through study on methods for establishing velocity field, the technology of establishing velocity field on the basis of combining such information as seismic velocity, logging, drilling and structural horizon is developed, and the velocity field reflecting the macroscopic law of velocity distribution is obtained, which is in good agreement with the well. Integrating the concept and application of seismic velocity, this paper defines the correlation of various types of velocity and its applicability, providing a complete velocity field solution for different phases of seismic exploration. Based on coordinate positioning and unified format transformation of seismic velocity data, the velocity base of all over Dongpu Sag is established, supporting seismic imaging, variable velocity mapping, and prediction of regional formation pressure technically, and yielding good results.

Key words: velocity field, horizon velocity, seismic imaging, variable velocity mapping, Dongpu Sag