Prestack depth migration by surface rotation controlled illumination
地表旋转控制照明叠前深度偏移

The conventional shot-record prestack depth migration costs a very expensive amount of computations for wavefield extrapolations. Based on the fast areal shot technology, the controlled illumination prestack depth migration aims to efficiently achieve the high-quality image of the target structure by controlling the source wavefield at the target. The synthesis operators needed for areal short records are obtained by inversely extrapolating the predefined source wavefield at the target upward to the surface. We propose the surface rotation controlled illumination, as a more efficient scheme of controlled illumination. This scheme performs target-oriented illumination control over source wavefield directly at the surface and can produce high-quality image of the target zones. A surface synthesis operator function is simply constructed by geometrically rotating a certain kernel synthesis operator, instead of complicated wave extrapolations. This new controlled illumination method is as efficient as the general areal shot record technology, moreover, it is more powerful to image the complicated target zone. The application of the proposed technique to the Marmousi model gives a very ideal image of the deep complex structure.