Non-Equilibrium Interactions Between Heavy Oil and Liquid Propane

Abstract

In this study, we use a custom-designed visual cell to investigate nonequilibrium interactions between liquid propane (C3(1)) and a heavy oil sample (7.2°API) at 55°C. The heavy oil sample is taken from Clearwater Formation located in Western Canadian Sedimentary Basin (WCSB). We inject C3(1) into the visual cell containing the heavy oil sample (pressure buildup process) and allow the injected C3(1) to interact with the oil sample (soaking process). After the pressure buildup process, we observe three phases in the visual cell: 1) heavy oil (0.67 mol), 2) liquid C3 (C3(1),0.60 mol), and gaseous C3 (C3(g), 0.20 mol). We measure visual-cell pressure and observe the C3-heavy oil interactions during the pressure buildup and soaking processes. Nonequilibrium interactions occurring at the interfaces of C3(1)-heavy oil and C3(1)-C3(g) are recorded over time. The results show that complete mixing of heavy oil with C3(1) occurs in two stages. First, upward extracting flow of hydrocarbon components from bulk heavy oil phase toward C3(1) phase form a distinguished layer (L1) during the soaking process. The extracted oil components become denser over time and move down (draining flows) towards the C3(1)-heavy oil interface due to gravity. The gradual color change of L1 from colorless to black suggests the mixing of hydrocarbon components from heavy oil. After L1 becomes homogenous, a second layer (L2) is formed at the upper part of the bulk C3(1) phase (above L1). Extracting and draining flows becomes active once again, leading to mixing of oil components from L1 into L2. At equilibrium condition, heavy oil and C3(1) are completely mixed and form a single homogenous phase.

Propane–Bitumen Interactions during Cyclic Solvent Injection─A Cold Lake Case Study

“…Furthermore, they concluded that the color of C 3,L would be darker if the concentration of heavier hydrocarbon components in C 3,L increases. Yassin et al studied the nonequilibrium interactions between CO 2 and oil and their findings about the formation of a uniform dark liquid phase are consistent with the findings of Athar et al and Eghbali et al Further detail about the findings of Yassin et al can be found elsewhere . Based on our observations and the reviewed literature, it can be concluded that the change in the color of propane from transparent to mild yellow during depletion in Test 1 and the formation of a yellow liquid phase in Test 2 and a dark liquid phase in Test 3 indicate the extraction of bitumen components by propane.…”

“…In this regard, the extraction mechanism in heavy oil and bitumen systems is less significant than that in the light oil . Athar et al evaluated the nonequilibrium interactions between propane and heavy oil using a visualization cell. , Based on their observations, propane may be mixed with bitumen as a result of extracting and draining flows. Ahadi and Torabi suggested that for a multiple-cycle CSI, the contribution of the extraction mechanism in heavy oil recovery is lower for the subsequent cycles.…”