Performance and Economic Analysis of SAGD and VAPEX Recovery Processes

Heavy oil has attracted global attention because of its significant volume of original oil in place. However, there are several economic and operational challenges associated with heavy oil recovery due to its high viscosity and high density. Recently, steam-assisted gravity drainage (SAGD) and solvent vapor extraction (VAPEX) recovery processes have been introduced to enhance heavy oil recovery. Although SAGD recovery process achieves high oil recovery, many drawbacks are related to this process, such as produced water treatment and huge amount of water and energy required to generate steam which leads to significant CO2 emissions. On the other hand, VAPEX recovery process has many challenges such as low production rates and potential sensitivity to reservoir heterogeneity. The drawbacks of SAGD could minimize its economic profitability compared to VAPEX process. Therefore, the objective of this work is to model and evaluate the two recovery methods from the economic point of view and based on the achieved net present value (NPV). Several sensitivity studies are applied on SAGD and VAPEX to analyze the effect of different operation parameters and different reservoir conditions. The effects of aquifer and initial oil viscosity on the recovery performance of SAGD and VAPEX are analyzed. In all the cases considered, VAPEX achieved higher NPV than SAGD by at least 70%, although SAGD has higher oil recovery factor. This research shows and confirms that VAPEX is more economic profitable recovery method and it is a step forward to eliminate CO2 emissions associated with thermal recovery process.