In this study, the effects of emulsion generation in a steam chamber formed in oil sands reservoir have been studied for bitumen production using Steam Assisted Gravity Drainage (SAGD).Some viscosity measurements of heavy oil emulsion were performed to investigate the characteristics of emulsion at different values of W/O, shear rates, pressures and temperatures. Based on these results, a numerical model of viscosity change was presented for the emulsion generation. The numerical simulations of the SAGD bitumen production were also carried out based on the model of viscosity change to estimate distribution of emulsion, water, and bitumen at steam chamber boundary and effects of emulsion on bitumen production behavior. With a model named SAGD-Emulsion Model, we highlighted that recovery factor of bitumen was higher than that of conventional SAGD simulation because higher water content would invariably allow bitumen to flow at higher relative permeability. The increase in viscosity was expected to induce delay of bitumen production.
Steam Assisted Gravity Drainage (SAGD) method is widely used to produce bitumen from oil sands reservoir. The API gravity of bitumen is less than 10° (i.e. specific gravity=0.9994)and its mobility at reservoir condition is nearly equal to zero. In general, two types of techniques, including open pit mining and in-situ recovery that has been a commercial method, are applied to produce bitumen from oil sands. SAGD method is one of the in-situ recovery method. In SAGD method, two horizontal wells are used as injector and producer. Steam is injected into the reservoir from the upper horizontal injector to head bitumen in order to decrease its viscosity from order of 106 cp to less than 10 cp. Heated oil and steam condensate are produced simultaneously from lower horizontal producer by gravity. Some experimental studies on SAGD process have been conducted by independent researchers. Numerical modeling of effective phenomena have been observed in these experiments and their applications to commercial field receive attentions from some researches. Al-Bahlani and Babadagli (2009) have reviewed current status and future issues of SAGD in terms of experimental and numerical simulation studies. They referred emulsification in the reservoir as one of these topics. Figure 1 shows the mechanism of a typical SAGD process and in-situ emulsification occurring in the steam chamber (Sasaki et al. 2002).