Reservoir fluid substitution effects on seismic profile interpretation : a physical modeling experiment

摘要

P-wave seismic surveys are performed on realistic physical models of a reservoir formed ofudinterbedded sand and shale layers and filled with gas, water, and oil. They show characteristicudbehaviour which can be used to distinguish between fluids, with significant implications for theudinterpretation of time-lapse experiments. Discontinuous reflections originate in gas-filledudreservoirs, with widely varying amplitude compared to oil- or water-filled reservoirs. Anomalousudchanges in seismic amplitude difference attributes for reflections within the reservoir are seen forudgas/oil substitution. Oil/water substitution results in only weak variations of reservoir elasticudproperties, thus amplitude difference attributes may be unsuitable for monitoring changes inudoil/water saturation. However, direct differences between the time traces are strong. On time-lapseudsections, strong amplitude difference anomalies do not necessarily correspond to the region whereudthe fluid variations occur; this is significant for monitoring oil field development by waterudinjection.