Seismic Technologies for Unconventional Reservoir Descriptions: Wamsutter Field Case Study

Abstract As part of a significant seismic technology effort, the BP Wamsutter Seismic Integration team conducted two field trials during 2006/2007- a surface seismic field trial and a borehole seismic field trial. The borehole seismic field trial consisted of a 3D Vertical Seismic Profile (VSP), as well as a four-well crosswell seismic campaign. The 3D VSP was acquired to further our understanding of seismic technical limits within the field, demonstrate the value of enhanced temporal resolution to reservoir characterization, and to test the viability of borehole seismic as a development tool for infill planning. The complex, heterogeneous, and thin-bedded nature of these tight reservoir sandstones make detailed reservoir characterization from surface seismic data extremely challenging. For Wamsutter, pre-acquisition 1D modeling from existing well data allowed theoretical limits of vertical seismic resolution to be compared to existing seismic data. Significantly higher frequencies (double the bandwidth) were successfully achieved with the 3D VSP as compared to existing and newly acquired surface seismic data. Prestack depth migration of the 3D VSP yielded excellent imaging results, which have allowed enhanced stratigraphic description of a very complex reservoir. Additional work explored the potential to use 3D VSP in conjunction with the surface seismic data for seismic imaging without a velocity model. Analysis, interpretation and integration of the VSP data has greatly progressed our understanding of the potential increase in the value of "designer" or fit-for-purpose seismic across the Wamsutter Field and beyond.