Experimental PVT Property Analyses for Athabasca Bitumen

Abstract

Abstract Extra heavy oil and bitumen reservoirs constitute huge volumes around the world and are attracting attention as alternative energy resources while the light oil reserves diminish. Thermal recovery and steam based methods are the most widely used recovery methods applicable to these highly viscous deposits. Study of steam injection in porous media containing viscous oil requires a good understanding of the physical properties of both reservoir rock and fluid. In particular, there are some bitumen properties that are needed for simulation studies and the most reliable source for these data is laboratory tests. This paper presents experimental study of some PVT properties of Athabasca crude oil to help provide input data for further numerical studies. Viscosity of Athabasca heavy crude was measured using a rotational viscometer up to 300 °C. This viscosity data is a more reliable input for simulation purposes. Athabasca oil was characterized by gas chromatography analysis to C39+. No significant amount of components lighter than C9 was observed. Whole sample molar mass was measured to 534 g/mol by cryoscopy. Density at standard conditions of 1 atm and 60 °F was measured to 1.0129 g/cm3 by a density measuring cell. Density and molar mass of the C39+ fraction were also determined. Density measurements were performed in the temperature range 120–195 °C as well where the density was found to vary in the range 0.95–0.90 g/cm3. A formula was derived based on experimental density data to predict Athabasca bitumen density in the temperature and pressure range studied. The interfacial tension between oil and steam was measured in the temperature range 120–220 °C by the pendant drop method. The interfacial tension was determined to be between 25 and 18 mN/m with a decreasing trend in the temperature range studied. The results presented here can be used as reference data for studies related to Athabasca bitumen.