The impact of non-swelling clays on Steam-Assisted Gravity Drainage (SAGD) performance was studied in this work. Two SAGD experiments were conducted on a Canadian bitumen by preparing the reservoir rocks with two different non-swelling clays; kaolinite (SAGD1) and kaolinite (90 wt%) and illite (10 wt%) (SAGD2). Change in clay type from kaolinite to a mixture of kaolinite and illite resulted in 15 wt% lower cumulative oil recovery. The role of clays and their interaction with crude oil fractions; namely Saturates, Aromatics, Resins and Asphaltenes (SARA fractions), on process performance was investigated through control experiments under optical and scanning electron microscopy. Pseudo blends of clays and SARA fractions revealed that kaolinite-asphaltenes interaction in SAGD1 occurs at steam condition, however, the same interaction happens for kaolinite-illite mixture at liquid water condition. It has been observed that while kaolinite-asphaltenes interaction is a direct interaction, 10 wt% illite addition to clay (SAGD2) causes an indirect interaction. This indirect interaction occurs due to mainly aromatics-clays association. Clays in SAGD2 were observed to be carried inside asphaltenes clusters. Since aromatics are soluble in asphaltenes, initially a black colored microscopic image was obtained. Upon the evaporation of aromatics, it has been observed that clays still preserve their original white color, however, stuck in asphaltenes clusters. Thus, our results concluded that not only heavy and polar fractions of crude oil, but also non-polar fractions may play an important role in oil displacement during SAGD.

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