Enhancing Subsalt Imaging of DAS-VSP Data Using a Structurally Adaptive Aperture

3D DAS-VSP surveys have the ability to complement surface seismic data to provide a holistic subsalt image and illumination. However, the DAS-VSP geometry intrinsically has limited angular coverage which leads to strong swing artifacts that contaminate and degrade the seismic image. To enhance the image quality of DAS-VSP data, the authors propose to use a structurally adaptive aperture in reverse time migration to confine the image only to those within a predefined angular range. Application of the algorithm to one field DAS-VSP data collected in a complex salt environment clearly shows significant uplift in the subsalt image.