Analysis of time-lapse difference AVO with the Pouce Coupe field data

Shahin Jabbari, David D'Amico, Jeff P. Grossman, Brian H. Russell, J. Helen Isaac, Kristopher A. Innanen

Time-lapse seismology is a cost-effective approach for monitoring the changes in the fluid saturation and pressure over a period of time in a reservoir, in which multiple seismic surveys are done at different time intervals and then compared to see reservoir changes. A multicomponent time-lapse seismic data set was acquired during hydraulic fracturing of two horizontal wells in the unconventional Montney Reservoir at Pouce Coupe Field in the Peace River area by Talisman Energy Inc. In this study, we analyze this data to validate derived linear and nonlinear theoretical results for the time-lapse amplitude versus offset (AVO) difference during the change in a reservoir from the baseline survey relative to the monitor survey. We first generate the well tie to determine the location of the reservoir on the seismic data at the Montney Formation. Synthetic logs for P- and S- wave velocities and density are then generated for the monitor survey. Analyzing this data set at the baseline and monitor surveys shows that the linear approximation is good enough to estimate time-lapse AVO difference. This is consistent with the fact that the Pouce Coupe data set has a low baseline contrast between the cap rock and reservoir and a low time-lapse contrast from the baseline survey to the time of the monitor survey. The upper layer of the Montney Formation or Doig, with a larger baseline contrast, is also analyzed to evaluate the theoretical results.