Utilising information from VSP data to improve reservoir characterisation

Abstract

In this work we use VSP data to help solve practical exploration problems. In particular, we show how VSP data can be used to quickly assess the response of various seismic attributes. Specifically, we use downgoing energy to evaluate and relate anomalous behaviour of seismic attributes to changes in effective stress. Selected attributes are then computed on up-going VSP energy using later arrival times and, if sensitivity with respect to changes in effective stress is retained, they are subsequently computed on surface seismic data. Such simplified VSP-based analysis enables quick and efficient qualitative assessment of variations in lithology, geo-pressure, or other rock properties under investigation. We also discuss how multi-offset VSP data can be used to speed up pre-stack depth migration (PSDM) of surface seismic data in areas where anisotropy is non-negligible and typically not fully defined.