Method for optimizing migration fields using time slice analysis

摘要

A method for imaging multi-directional fractures in a homogeneous basement utilizing time slices or depth slices to select velocity fields that yield the optimal lithological image of said fracture patterns, especially in 3-D seismic cubes. More specifically, the method involves definition of small data subvolumes within a larger 3-D data volume. The data subvolumes are selected to image a specific target. The subvolumes are imaged multiple times, using prestack time migration with different velocity models. Each of the migrated subvolumes is timesliced at selected time intervals. All timeslices corresponding to a given time are then gathered together from the different migrated subvolumes. Each of the constant time timeslice datasets are run through velocity analysis. In one preferred embodiment, the seismic data itself is used to determine velocity. In another preferred embodiment, velocity is determined through semblance techniques.