Designing borehole seismic VSPs for complex subsalt or near-salt reservoir evaluation

Allan Campbell, Les Nutt, Ric Smith, and Hungyu Chang discuss the advantages of Schlumberger’s latest approach to vertical seismic profiles in challenging subsalt environments such as the Gulf of Mexico. Borehole seismic technology used to acquire vertical seismic profiles (VSPs) has proven successful in gathering information and gaining understanding of complex subsalt or near-salt structural environments. However, the success for acquiring any type of VSP survey that will impact drilling and development decisions under these challenging conditions is highly dependent upon careful threedimensional (3D) pre-survey planning and modelling as well as efficient seismic data acquisition and processing techniques. An integrated borehole seismic system from Schlumberger has been developed to help operators accomplish this by optimizing all aspects of borehole seismic services during drilling, acquisition, and processing operations. The technology is discussed along with three VSP survey examples of its application, from job planning through data acquisition, transmission, processing, and results interpretation.