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An Efficient Dip Filtering Approach to Improve VSP Imaging Quality

Summary VSP data usually generates a higher resolution seismic image in the region of the borehole than surface seismic, but its imaging result often suffers migration artifacts due to the fact that there are fewer and fixed borehole receivers and therefore low and uneven CDP folds in a VSP survey. A common method to suppress the VSP migration artifacts is to reduce the migration aperture to a small angle. However, a small aperture angle can often fail to image significantly dipping structures. Here, we present an efficient and effective dip filter consistent with the local velocity model in VSP migration, which preserves true dip structures and in the meantime suppresses migration artifacts. Examples from both synthetic and field walkaway VSP data demonstrate that the dip filter consistent with the local velocity model effectively improves VSP imaging quality and thereafter interpretation of the VSP data.