Time-lapse seismic and AVO modelling, White Rose Field, Newfoundland

Ying Zou, Laurence R. Bentley

We have applied FluidSeis, well logs and AVO modelling to investigate the change in seismic response due to fluid substitution in the White Rose Field. The White Rose Field has a gas cap, an oil leg and a water drive. Three scenarios are presented. A water drive has water replacing the oil in the oil leg up to residual oil saturation. A gas drive has gas replacing the oil in the oil leg up to residual oil saturation. A final scenario has gas invading the upper half of the oil leg and water invading the lower half of the oil leg. Using PVT data and inferred post-production saturation, new sonic logs and density logs are generated. Synthetic seismic and AVO models are compared before and after production. Reflection coefficients at the gas-oil contact (GOC) and the oil-water contact (OWC) change in magnitude approximately 15%. The synthetics indicate that P-P and PS AVO responses can be used to observe the changes in fluid distributions. The change in density due to fluid substitution appears to be the major factor in changing the seismic response. This study indicates that the White Rose Field is a good candidate for time-lapse seismic monitoring of fluid movements.