Method for depth imaging multicomponent seismic data

摘要

The present invention relates generally to a method of geophysical exploration and more particularly to a novel method for imaging multicomponent seismic data to obtain better depth images of the earth's subsurface geological structure as well as better estimates of compressional and shear wave interval velocities. In particular, measures are obtained of imparted seismic wavefields incident on reflecting interfaces in the earth's subsurface and of resulting seismic wavefields scattered therefrom. The incident and scattered seismic wavefields are employed to produce time-dependent reflectivity functions representative of the reflecting interfaces. By migrating the time-dependent reflectivity functions, better depth images of the reflecting interfaces can be obtained. For a dyadic set of multicomponent seismic data, the dyadic set of multicomponent seismic data are partitioned so as to separate the variously coupled incident and reflected wavefields in the recorded multicomponent seismic data. The incident and reflected wavefields are cross-correlated to form time-dependent reflectivity functions. The time-dependent reflectivity functions are then iteratively migrated according to a model of wavefield velocities of propagation to obtain better estimates of the compressional and shear wave interval velocity. The migrated reflectivity functions can then be stacked to produce better depth images of the earth's subsurface geological structures.