Comprehensive experimental study and numerical simulation of vapour extraction (VAPEX) process in heavy oil systems

Abstract

There are significant heavy oil and bitumen resources in Canada. Global energy demand is rising while environmental constraints make heavy oil recovery more challenging. Therefore, looking for an economically viable and environmentally-friendly heavy oil recovery technique is essential. Recently, solvent-based heavy oil recovery techniques (i.e., VAPEX) have attracted attention due to their economic and environmental advantages over thermal methods. In this research, an extensive experimental and numerical simulation study on the VAPEX technique was carried out to provide more in-depth information about key parameters which affect the ultimate performance of the VAPEX process. For this purpose, VAPEX experiments were conducted in two large-scale physical models and various solvents were utilized. PVT experiments were also carried out, and CMG's STARS TM was used for numerical simulation studies and to history-match the experimental results. Image analysis of the VAPEX chamber evolution showed that the highest sweep efficiency was observed after injecting propane, followed by butane, a propane/carbon dioxide mixture, a propane/methane mixture, carbon dioxide, and methane. The experiments were simulated numerically, and satisfactory history-matching results were achieved. The major difference between the experimental and simulation results was observed after the first breakthrough of the solvent. In addition, the results showed that injection and production well configurations significantly affected the recovery performance of the process. A longer distance between the injection and production wells alongside the drainage height will increase the production rate in VAPEX.

Numerical Study of Single Well Vapor Extraction Process

“…Later, Rezaei et al [7] showed that, unlike SAGD process, the oil-wet condition of the formation positively impacts the oil production rate. To improve the economic viability of Vapex process, Torabi et al [8][9][10] suggested injecting the noncondensable gases like CO 2 with a hydrocarbon solvent. Using numerical simulation they found out that CH 4 or CO 2 coinjection is a viable option and results in equal or greater recovery factors in most cases.…”