Towards application of nonlinear time-lapse AVO to the Pouce Coupe data set

Shahin Jabbari, Jeff P. Grossman, J. Helen Isaac, Kristopher A. Innanen

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. An increase in pore pressure has been induced following the hydraulic fracture operations in the unconventional Montney shale reservoir. This will affect the seismic parameters including P-wave and S-wave velocities and density of the subsurface, which can be approximated by applying time-lapse AVO (amplitude variation with offset) analysis methods. In this study, we are analyzing this data to validate our linear and nonlinear theoretical results for the difference data during the change in a reservoir from the baseline survey relative to the monitor survey. Prestack time migrated common depth point gathers (PSTM CDP) for the baseline and two monitor surveys are used. Due to the tight nature and low permeability of the Montney reservoir, the injection of fluid into the reservoir during the fracture operations will affect only the close vicinity of the fractures. For this reason, the change in P-wave velocity should be investigated in the vicinity of the hydraulic fractures in the horizontal wells. We have initiated the investigation and are analyzing methods to quantify the P-wave time-lapse difference AVO, and now wellpositioned to pick events whose time-lapse AVO signatures may be analyzed for nonlinearity. Also monitoring any converted wave time-lapse changes can lead to modeling the hydraulic fracture stimulation. Data analysis is still under review pending more well data information.