Pore Scale Investigations On The Dynamics Of Sagd Process And Residual Oil Saturation Development

Since its invention, steam assisted gravity drainage (SAGD) demonstrated to be a viable technology to recover heavy oil and bitumen from oil sands. However, the field experience over the last two decades indicated that, oil recovery factor is below the expected values determined from the scaled physical lab models. Knowing that the reduction of the high cost of steam is quite difficult, efforts should be made towards the improvement of the recovery factor (or reducing the residual oil saturation, Sor). Thus, the analysis of the development of Sor at the macro and micro scales turns out to be a critical problem. Sor is impacted by the dynamics of the SAGRD process, reservoir properties and operational conditions. The objective of this dissertation is to systematically investigate the physical reasons behind the formation of Sor at the micro scale focusing on the effects of the dynamics of SAGD and characteristics of the reservoir. This research begins with a study on Sor development in capillary tubes considering variable temperatures. Then, Computational Fluid Dynamics (CFD) approach is used to investigate the development of Sor at temperature and pressure conditions that are difficult to reproduce through physical experiments. Using the observations through these analyses and data, the effects of a temperature gradient on the flow dynamics, oil recovery and relative permeabilities are investigated analytically for single and bundle of cylindrical capillaries. Finally, the dynamics of the SAGD process and the development of Sor are studied through 2-D glass bead models visually. The results show that the Sor is a dynamic property that depends on the balance of the acting forces, the temperature and the temperature gradient. A detailed analysis is carried out starting from the physics in a pore. The displacement and trapping mechanisms during the formation of the steam chamber are elucidated and it is demonstrated how those affect the residual oil saturation development. It is also shown how the pore size, the heterogeneities and the wettability are responsible for low oil recovery factors to a great extent.