An Experimental Investigation of Thermal Marangoni Phenomena on Recovery of By-passed Oil in a Fractured Matrix

Gas injection is one of common EOR methods in oil reservoirs. However, it might not contact with whole oil and ride over the liquid phase or channels through the high permeable paths of the reservoir and bypasses some oil. Marangoni phenomena is an effective mechanisms in bypassed oil production and causes convective flow from a point with low IFT to one with high IFT. This study reports the role of thermal Marangoni phenomena in the recovery of bypassed oil experimentally. Core flooding experiments have been conducted under high pressure at various temperature, in immiscible regime due to the existence of interface between phases and into two categories of “isothermal” and “non-isothermal”. In isothermal design, the degree of freedom is zero, and there is no Marangoni flow. But also, in non-isothermal category, Marangoni flow might increase or decrease the amount of recovery based on the interfacial tension gradient direction. Analytical investigation of experiments have been conducted through dimensionless analysis and evaluation of viscose, capillary, gravity and molecular diffusion forces. Therefore, experiments have been designed by determination and investigation of dimensionless numbers in such a way that similarity of cross-flow forces like gravity, capillary and viscosity have been considered. Therefore, the role of Marangoni flow can be verified by comparison of recovery factor. Furthermore, carbon dioxide is used to be injected in fracture due to widespread application of this gas in the oil industry. The results of experiments show that Marangoni flow is one of the effective mechanisms in recovery of bypassed oil under high pressure and temperature. This phenomena can dominate capillary force and move the trapped oil in matrix. The magnitude of this flow is proportional to temperature difference of gas and oil in their interface. Increase or decrease in oil recovery of similar experiments, indicate the role of this phenomena in porous media.