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SPE
SPE 19690 Foam Application in an Oil Sands Steamflood Process
G.S, Kular, Alberta Oil Sands Technology & Research Authority; K. Lowe, Amoco Canada Petroleum Co,; and D. Cmmbe, Computer Modelling Group
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INTRODUCTION The Athabasca tar sands of Northern Alberta are estimated to ccntain approximately 127 billion cubic metres of bitumen, Although the avalaible technology and to a large extent the current world oil price cannot fully support the commercial development of this vast resource; it is envisaged that more efficient recovery methodspresently being tested may allow its future development. The Athabasca tar sands deposit offers excellent reservoirs in tmns of porosity, oil saturation, and pay thickness, however the lack of mobility within the virgin sands does not allow for practical injection and production rates. ‘lb mobilize the highly viscous bitumen (106 mPa.s) the, viscosity must be lowered significantly by using thermalrecovery methods such as steam flooding and steam stimulation. Due to the negligible initial i~ectivity offered by the formation, the fluid has to be ir@+cted above fracture pressure, Hydraulic fracturing has been used in this region in an effort to try and develop interwell communication at the base of the reservoir. However due to the isotropic in-situ stress conditions existing at the depths ofinterest the directional control of these fractures is unpredictable. This is because, pore pressure increase due to fluid leak-off, thermal expansion and fracture loading may alter the stress fields inducing a change in the fracture orientation, or resulting in multi-directional fractures.2~9 This lack of fracture control along with gravity segregation of steam results in heat overlay early in 619This paper outlines a foam fieid test presently being conducted in the McMurray formation of the Athabasca Oil Sands in Alberta. The test objective is to determine the viability of using foam as a mobility control and diverting agent for steam; which has a tendency to wernde the pay zone. Prior to initiating the test various surfactants were tested in the laboratory by injecting with steaminto a sand pack, The steam-surfactant mixture that resulted in the greatest pressure increase (ie. the great.d reduction in tbe gas mobility) was selected for the field test, Laboratory results also indicated that the simultaneous iqjection of surfactant, steam and a non-condensable gas provided a higher pressure increase compared to batching the surfactant ahead of the steam and gas. The earlyresults from the field qualitatively substantiate the laboratory pressure results. Numerical modelling using Computer Modelling Group’s “Steam and Additive Resemoir Simulator” (STARS) was used as a pre-test directional tool, as well to analyze and predict long term steam-foam application performance. Reservoir geology which has been of major consequence in the subject reservoir recovery process wasaccounted for in the numerical model,

Reference and Illustrations at end of paper

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FOAM APPLICATION IN AN OIL SANDS STEAM PtOOD PROCESS the life ofthe p~eck The heat overlay and later the heat oufflow fkom the pattern is intmmitled in some of these reservoirs, where the main pay is overlain by high watar mobility zones; which act as a conduit for the injected fluids. Therefore after...