Steam-based enhanced oil recovery methods like Steam-Assisted Gravity Drainage (SAGD) for extracting extremely heavy oils and bitumen are energy intensive and require high steam volumes with steam generation resulting in significant greenhouse gas emission. The oil industry has resorted to adding solvent to steam aiming to overcome these limitations. A new analytical model is developed for describing solvent co-injection with steam (solvent-SAGD) process in relation to constant injection rate, for the first time, based on the combination of an overall solvent mass balance, heat balance and volumetric oil displacement and Darcy's oil rate using a mixture viscosity model as a function of temperature and solvent concentration ahead of a moving vapor-oil front which satisfy the equilibrium in the system. The objectives of this work are to evaluate the performance of the solvent-SAGD process by predicting; vapor chamber growth, oil production rate, solvent production rate, solvent loss (or solvent retention) rate, and the effect of solvent type and concentration on the process. The mechanism of oil recovery by steam with added solvent is not clear. Given the controversy regarding the use of solvents with steam, by developing the new mathematical approach, this study is intended to explain whether solvent-SAGD process increases oil recovery compared to SAGD or not. If any, which solvent results in better recovery. The results of this approach give a better understanding of the oil production mechanism during the solvent-SAGD process by interconnecting vapor chamber conditions and the conditions of heated and diluted oil ahead of the moving vapor-oil interface. The results show that mass transfer occurs over a scale of centimeters, while heat transfer scale is of the order of meters. The rate of solvent retention increases over time, while the production rates of solvent and bitumen decrease. Also, it is shown that the solvent-SAGD process which is a combination of heat and mass transfer would yield a higher oil recovery, if viscosity reduction from dilution at a lower temperature is greater than viscosity reduction by temperature in the SAGD process, for the same total injection rate.

基于蒸汽的强化采油方法，例如用于提取极重油和沥青的蒸汽辅助重力排水（SAGD），是能源密集型的，并且需要大量蒸汽并产生蒸汽，从而导致大量温室气体排放。为了克服这些限制，石油工业已向蒸汽中添加溶剂。基于整体溶剂质量平衡，热量平衡和体积油排量的组合，首次开发了一种新的分析模型，用于描述与蒸汽恒定注入速率相关的溶剂与蒸汽共注入过程（solvent-SAGD）。使用混合粘度模型的达西油率是温度和溶剂浓度的函数，该温度满足运动的汽油前沿前方的要求，满足系统中的平衡要求。这项工作的目的是通过预测来评估溶剂SAGD工艺的性能。蒸气室的生长，产油速率，溶剂产生速率，溶剂损失（或溶剂保留）速率以及溶剂类型和浓度对工艺的影响。蒸汽加溶剂回收油的机理尚不清楚。考虑到有关蒸汽中使用溶剂的争议，通过开发新的数学方法，本研究旨在解释与SAGD相比，溶剂SAGD工艺是否提高了石油采收率。如果有的话，哪种溶剂可以提高回收率。该方法的结果通过在移动的气-油界面之前互连蒸气室条件和加热的稀油条件，从而更好地理解了溶剂-SAGD过程中的产油机理。结果表明，传质发生在厘米范围内，而传热规模约为米。溶剂保留率随时间增加，而溶剂和沥青的生产率降低。此外，还表明，如果在较低温度下稀释产生的粘度降低大于SAGD过程中温度降低的粘度降低，则结合热量和传质的溶剂SAGD方法将获得更高的采油率。相同的总注射速率。结果表明，传质发生在厘米范围内，而传热规模约为米。溶剂保留率随时间增加，而溶剂和沥青的生产率降低。此外，还表明，如果在较低温度下稀释产生的粘度降低大于SAGD过程中温度降低的粘度降低，则结合热量和传质的溶剂SAGD方法将获得更高的采油率。相同的总注射速率。结果表明，传质发生在厘米范围内，而传热规模约为米。溶剂保留率随时间增加，而溶剂和沥青的生产率降低。此外，还表明，如果在较低温度下稀释产生的粘度降低大于SAGD过程中温度降低的粘度降低，则结合热量和传质的溶剂SAGD方法将获得更高的采油率。相同的总注射速率。