The potential of shear-wave VSPs for monitoring recovery: A letter to management

Much of the ultimate success (or failure) of hydrocarbon recovery depends on the assessment, usually implicit, of the internal crack-, pore-, and stress-geometry, and pore fluids of the reservoir rock. It also depends on the estimation (again usually implicit) of the changes to these quantities as the secondary and tertiary production or enhanced oil recovery (EOR) proceeds. At present, we are able to recover only a small proportion of the oil in a reservoir. Amos Nur wrote in TLE (September 1989): “The most obvious way to significantly improve recovery…is to obtain much better descriptions of the internal structure…” Recent advances in seismology, reported at the SEG Research Workshop on Recording and Processing Vector Wave Field Data (Snowbird, Utah, August 1989), have shown that many details of this internal structure may be monitored in situ by appropriate shear-wave (three-component) VSPs.