A Multicomponent Walkaway Vertical Seismic Profile Experiment in a Heavy Oil Reservoir
A multicomponent walkaway VSP experiment was successfully processed and used to predict rock properties in a heavy oil reservoir. Post-stack image and pre-stack gathers were made for inversion and AVO analysis. A common shot reflectivity gather was also created for AVO study at the VSP well location. P and S-wave impedance, reflectivity, Vp/Vs and density were studied. AVO attributes and their crossplots were analyzed. Furthermore, AVO Lambda-mu-rho analysis and AVO modeling were conducted. The analyses helped to identify different lithologies and changes of fluids in the target reservoir. The study showed no obvious gas effects in the target interval, a finding validated by production data. The converted-wave data had good resolution. PP-PS joint inversion added more details to P-wave inversion only. This case study demonstrated that multicomponent VSP is an effective tool to predict rock properties, characterize the reservoir, and monitor production.