Phase Behavior and Thermophysical Properties of Peace River Bitumen + Propane mixtures

Abstract

Oil sands bitumen is increasingly recovered by injecting steam into reservoirs using the energy intensive Steam assisted gravity drainage (SAGD) process. Interest in improving recovery and energy efficiencies have led to an interest in injecting light hydrocarbons along with or instead of steam as a basis for the development of improved production technologies. Propane and mixtures including propane as a principal component are among the leading potential injectants. In this work, the phase behavior, phase composition and phase densities of propane + Peace River bitumen mixtures are studied using a variable-volume X-ray view cell in the temperature range between 303 K and 393 K at pressures ranging from 1 to 6 MPa. This apparatus permits the study of mixtures that are opaque to visible light and provides real time phase volume and liquid phase density measurements. Pressure-temperature at fixed composition, and pressurecomposition at fixed temperature phase diagrams, and temperature-composition and pressure-temperature phase projections are presented, along with the saturated compositions and densities of the co-existing bitumen saturated propane liquid (L1) and propane saturated bitumen liquid (L2) phases. The phase behavior of this pseudo binary mixture can be categorized as Type III according to the van Konynenburg-Scott nomenclature. One of the key findings is the unexpected magnitude of the volumes of mixing, particularly for the L1 phase. Saturated L1 and L2 phases are both significantly less dense than liquid water phases at the same temperatures and pressures. The data set is expected to provide a benchmark for process development and process design calculations for ongoing bitumen production and de-asphalting applications.