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Steam injection in heavy oil reservoirs does not only change the fluid properties, but also affects the interfacial tension of aqueous phase/hydrocarbon and the wettability of sand/hydrocarbon systems. Understanding the alteration of those properties is crucial for a successful steam injection, and it is expected to play an important role in heavy oil recovery from sands. However, studies on the measurements of interfacial properties of steam, heavy oil, and sand systems have not been well documented in the literature. This paper describes a new experimental technique and procedure which have been developed for generating steam within a small optical cell at high saturated pressure and temperature conditions. After that, image processing technique was applied to measure the interfacial tension of heavy oil/steam and the contact angle of heavy oil/steam/quartz systems. They have several advantages which are fast, relatively cheap and reliable. They potentially would have a wide range of applications in steam injection such as measuring the rock wettability, examining the effects of steam acidity and steam quality, and optimization for the purposes of prevention and/or reduction in damages to the formation. The experimental results indicate that steam injection has caused the alteration of interfacial properties. Interfacial tension measured in steam/heavy oil systems tends to decrease, while contact angle measured in quartz/heavy oil/steam systems tends to increase at saturated temperature and pressure conditions. As the aging time increases, the quartz's wettability changes from mixed-wet to more oil-wet. [ABSTRACT FROM AUTHOR]