Target Oriented VSP Imaging - A Sparse-inversion Approach

For reservoir monitoring surface seismic data usually has lower than desired resolution due to propagation effects of the wavefield through the complex overburden above the reservoir. VSP data, on the other hand, suffers less from propagation loss and usually have a wider frequency content and higher resolution compared to the surface seismic data. However, conventional imaging techniques applied to VSP data cause imaging artifacts due to the limited aperture and irregular subsurface illumination. These images could be improved considerably by suppressing artifacts and improving image reliability, if imaging is approached as an inversion process. Furthermore, including the free surface multiples in this process will extend the illumination, especially away from the well trajectory. A target-oriented VSP imaging procedure, using a sparse-inversion approach, is presented.