Abstract

Steam Assisted Gravity Drainage (SAGD) has proven itself to be a commercial success in McMurray oil sands reservoirs. In this process, steam delivered into the reservoir mobilizes bitumen which then flows under gravity to the production well. A countercurrent flow situation results where steam rises and bitumen and condensate drains within the reservoir. Given the vertical and horizontal flow within the reservoir, SAGD performance is strongly affected by reservoir heterogeneity. In the field, poor SAGD performance commonly arises from two challenges: first, steam breakthrough from the injector to the producer and second, non-uniform chambers along the length of the well pairs. Flow control devices (FCDs) offer the potential to improve SAGD performance but it remains unclear how to place and design these devices to maximize steam conformance and minimize steam-to-oil ratio. Here, to understand the behavior of FCDs in SAGD operations, detailed reservoir simulations, including wellbore hydraulic modeling, are conducted in a simple clean sand model and a detailed point bar model dominated by inclined heterolithic strata. The study includes the use of FCDs on the injector only, the producer only, as comparisons to conventional well completions cases. The results indicate that SAGD performance improved by using FCDs with better control of steam breakthrough between the wells.

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