Gaussian Beam Migration for Free-Surface Multiples in VSP

The vertical seismic profiling (VSP) Gaussian beam migration is a imaging method with both computational efficiency and precision. It can get high-resolution structural features near the well. However, VSP based on primary reflection limited by observation system, which makes it unable to image for shallow structure at far offset. free-surface multiples in expand illumination range offset effectively. Therefore, (GBM) proposed. Firstly, ground pre-stack depth migration, decomposing plane wave improved adapted into geometry. We decompose records received well waves different directions according window centers of each direction independently. Secondly, through mirror velocity model receivers, are converted reflections involved method, thus, primaries used multiples. Finally, effectiveness robustness proposed verified theoretical practical data.