Effects of Reservoir Heterogeneities on the Steam-Assisted Gravity-Drainage Process

Summary The success of steam-assisted gravity drainage (SAGD) has been demonstrated by both field and laboratory studies mostly on the basis of homogeneous reservoirs and reservoir models. A comprehensive understanding of the effects of reservoir heterogeneities on SAGD performance is required, however, for wider and more-successful implementation. This work presents a numerical investigation of the effects of reservoir heterogeneities on SAGD using a stochastic model of shale distribution. Two flow regions, the near-well region (NWR) and the above-well region (AWR), are identified to decouple the complex effects of reservoir heterogeneities on the SAGD process. Numerical simulations are conducted with various realizations of shale distribution to compare SAGD performance in terms of the effects of NWR and AWR. Hydraulic fracturing is proposed to enhance steam-chamber development for reservoirs with poor vertical communication, and the feasibility of hydraulic fracturing is discussed in terms of in-situ stress and well orientation. Fracturing both injectors and producers is found to improve steam distribution, oil production rate, and the oil-steam ratio.