The invention relates to systems and methods for geophysical data processing, and in particular to seismic imaging systems and methods.
Generating images of subsurface structures is a key component of the search for oil and gas deposits. Accurate imaging decreases the chances of drilling expensive dry wells, allowing a reduction in the cost of oil exploration and production, and a reduction in dependence on foreign oil.
Kirchhoff migration methods are commonly used for seismic imaging. In Kirchhoff migration, the energy of an event on a trace is propagated to all possible reflection points in the model space. The propagation of the events may be done using methods that are generally related to Green functions. Travel-time tables may be used to characterize the time of propagation from the source defined by the trace to the image point and/or further to the reflector point defined by the trace. After all events on all traces are propagated, an image is generated by stacking (summing) all individual contributions. Stacking reinforces in-phase energy corresponding to true reflectors, and cancels out-of-phase energy that does not correspond to a true reflector.