TESTING AND HISTORY MATCHING OF ES SAGD (USING HEXANE)

The use of Expanding‑Solvent SAGD (ES‑SAGD) as a recovery technology in bitumen and heavy oil reservoirs has been shown to lead to accelerated oil recovery while reducing green house gas (GHG) emissions because it requires less steam (lower SOR) than equivalent pure SAGD recovery technology. As ES‑SAGD matures, there is need to provide additional understanding of the technology to assist in design, operational parameters selection and actual field execution of pilot or commercial scale projects. In the original patent of ES‑SAGD, hexane (or a pseudo‑hexane solvents mixture) was identified as the most suitable co‑injected solvent in term of accelerated recovery and better energy efficiency. Also, several lab‑scale and field‑scale numerical simulations have been published that provide additional understanding and optimization of the ES‑SAGD either with single‑component or multi‑component solvents. A recent paper also focused on the design of injection wells for ES‑SAGD using hexane as the co‑injected solvent. There exist propriety experimental results or data on ES‑SAGD with hexane as the co‑injected solvent, but to date there is no publicly available 2D scaled experimental data on the ES‑SAGD with hexane as the co‑injected solvent, hence the motivation for the work presented in this paper. Experimental results of ES‑SAGD (with hexane) were also compared with the equivalent SAGD. The 2 experiments, which were conducted at the Alberta Research Council_s Thermal gravity laboratory, are 2‑D high pressure/high temperature experiments and were conducted at 2100 kPag +/‑ 50 kPag. The comparison of ES‑SAGD and SAGD experiments shows that ES‑SAGD using hexane performed better than equivalent SAGD experiment. The energy consumption per unit oil recovered for ES‑SAGD is lower than that of the SAGD (11.5% less). The average oil recovery within the first 500 minutes (i.e. 11.3 years at field‑scale) for the ES‑SAGD process is also much higher (~10.93% higher). The results presented in the paper provide data that can be scaled to field and assist in the design, optimization and parameters selections when ES‑SAGD (with hexane or a pseudo‑hexane solvents mixture) is considered as a recovery technology.