Thermodynamics of Hydrocarbon Solvents at the Pore Scale During Hybrid Solvent-Thermal Application for Heavy-Oil Recovery

Abstract

Abstract Phase behavior of fluids at capillary conditions differs from that in bulk media. Therefore, understanding the thermodynamics of solvents in confined media is essential for modeling thermal EOR applications. The Thomson equation states that pore sizes have a control on boiling points of liquids in capillary channels. As pore spaces become smaller, boiling points become lower than normal boiling temperatures of the same liquids. The target of this paper is to inspect this phenomenon by physically measuring the boiling points of several solvents and compare them with the calculated boiling temperatures for different capillary structures. Furthermore, the feasibility and accuracy of the Thomson equation is investigated to check its applicability in heavy-oil recovery modelling. To do so, Hele-Shaw cells with several gap thicknesses (0.04, 0.45, 1.02, and 12 mm) are used to measure the boiling points of heptane, heptane-decane mixture, and naphtha. Experiments are repeated for the same solvents on homogeneous and heterogeneous micromodels to observe the phase behavior in a more realistic porous medium. Finally, the effect of surface wettability on boiling temperatures is examined in Hele-Shaw and micromodel experiments.