Monitoring Heavy Oil Recovery by Integrating Seismic Data with Reservoir Simulation

Abstract

The purpose of this research study was to monitor the recovery process of a heavy oil reservoir using the time-lapse seismic data in order to reduce the ambiguity of reservoir simulation. The sim2seis (simulation to seismic) procedure was applied in a cold heavy oil production with sand (CHOPS) reservoir located in western Saskatchewan, Canada to convert the pressure and saturation results to seismic attributes as a function of time. Qualitative and quantitative analysis of time-lapse seismic data was also performed to determine the changes in the elastic properties that occurred in the reservoir during hydrocarbon production. In the studied heavy oilfield, operated by Husky Energy Ltd, time-lapse seismic Amplitude versus Offset (AVO) analysis and inversion were also applied to detect the production related changes in the reservoir between the wells. Different time-lapse seismic techniques were applied to maximize the information taken from the seismic data and to increase the reliability of the seismic analysis. Although time-lapse seismic results were successful in identifying the anomalous zones, time-lapse seismic attributes were also extracted to highlight the changes observed in the reservoir and to better confirm and describe the physical properties of the anomalous zones. In addition, forward seismic modeling was applied to derive the AVO responses which should be expected in a typical CHOPS reservoir. The minimum thickness of the reservoir layer which can be resolved by the time-lapse seismic data was also determined by the forward modeling. To compare quantitatively the sim2seis results with the time-lapse seismic results, a rock physics model was also applied to link the reservoir simulation results to the seismic elastic properties and vice versa. This model attempted to mimic the conditions observed in the unconsolidated heavy oil reservoirs. In summary, this research study confirmed that the application of the sim2seis process can improve the characterization of a heavy oil reservoir in four dimensions in a quantitative sense. Different time-lapse seismic analyses were applied to extract the maximum information from the time-lapse seismic data and to identify the foamy oil zones and production footprints. This procedure leads to the improvement in the forecasting of the future reservoir performance.