| dc.description.abstract | In-situ combustion (ISC) is a very promising thermal enhanced oil recovery (EOR) method to recover heavy oils and bitumen as it has a high recovery rate and is applicable to use at a varied range of reservoirs. However, as ISC involves highly exothermic reactions and complicated reaction kinetics, it is challenging to predict its performance as compared to other EOR methods. The chemical reactions associated with the ISC process are numerous and occur over different temperature ranges. The reactivity of each reaction is controlled by the chemical kinetics. The oil composition and the rock mineralogy will also affect the reaction kinetics. Thus, the ISC performance predictions are only reliable if proper reaction models are formulated. This dissertation evaluated the ISC field performance by integrating the combustion tube and kinetic experiment results. The performance estimation of these processes is described under three distinct sections of this study. First, the role of oil composition and the effect of clay presence on ISC performance were studied through combustion tube experiments of 3 types of crude oil samples. Next, analytical modeling was done on the combustion tube results integrating with the reaction kinetic parameters. Finally, the reaction kinetics and modeling of ISC were performed to study the factors that affect ISC performance. The result shows that crude oil combustion performance varies depending on oil compositions. Clay presence aids combustion by increasing the oxygen uptakes on asphaltenes' surface area, which results in more coke formation. Asphaltenes dispersion is encouraged by resins and aromatics fractions.
Moreover, asphaltenes coagulation is enhanced due to saturates fraction. Water presence also aids the combustion process. Heavier fractions (resins and asphaltenes) dominate the reaction pathways, thus decreasing the energy requirement and generate a large heat making the combustion effective. Water and aromatics fraction interaction at elevated temperatures favors ISC reactions. Lastly, reservoir rocks also affect ISC performance. An increased amount of clay decreased the activation energies of the reactions and increased the heat of combustion, which was indicative of the catalytic properties of clay. However, the results might indicate that the clay-oil pair used in this study may have an optimum reaction at 9% clay content. In the presence of carbonate, calcite is generating more heat for combustion but increasing the activation energy needed for HTO region due to its interaction with aromatics. Meanwhile, the heat generation was reduced and the activation energy was increased when dolomite was the reservoir rock. This is due to dolomite interaction with resins. The approach in this dissertation is a fresh take on determining the reaction kinetics of the ISC process by coupling the combustion tube experimental results with the kinetics experiment. This study will help reduce the complexity of the process by trying to develop a simplified approach towards a better understanding of ISC chemical reactions for different types of crude oil and reservoir. | en |
