Monitoring of Steam Stimulation in the McMurray Formation, Athabasca Deposit, Alberta

Abstract

Because of injectivity considerations, injection schemes in the Athabasca deposit of Alberta often require creation of fractures. Bitumen recovery is linked to the heat and fluid distribution obtained in the reservoir. Hence, to optimize the performance of the process, one needs to monitor closely the mechanical and thermal disturbance caused by steam injection in the reservoir formation. The objectives of the monitoring program described in this paper were (1) to obtain input data for numerical simulation studies so that subsequent optimization of the process could be undertaken, (2) to verify assumptions/speculations on the process mechanisms, and (3) to obtain diagnostic information. Six wells were steam stimulated. The monitored data included tiltmeter records on all wells, injection-pressure/flow-rate data, produced-water salinity analyses, limited pressure-falloff analyses, data from a few pressure observation wells, first-order leveling, and self-potential (SP) and resistivity mapping. From these observations, the existence and nature of fractures around different wells were inferred. The study confirmed that a combination of various monitoring techniques enhances the reliability of interpretations. For obtaining process data in a cost-effective manner, monitoring programs that rely heavily on conventional data collection from injection and production wells are recommended.