Effect of Angle of Dip and Viscosity on the Fractional Flow Curve

In primary recovery, the natural energy of the reservoir is utilized to drive oil to the surface. However, as reservoir pressure declines, additional methods like waterflooding are employed to maintain reservoir pressure and improve hydrocarbon recovery. In most cases, during or after a waterflooding project, some pockets of oil are left undrained or bypassed or the possibility of viscous fingering, leading to viable residual oil saturation that could be of commercial quantity. This challenge has led to the concept of sweep efficiency to account for the percentage of the reservoir is that efficiently swept by the injected water probably due to the viscous nature of the fluid (viscosity), reservoir heterogeneity, complex interaction between the injected water and the reservoir rock and the angle of dip (either up or down dip). There is also possibility of early breakthrough of the water due to the injection rate, water quality, well configuration and oil viscosity. The aim of this study is to evaluate the effect of the angle of dip and the fluid viscosity on the fractional flow curve. From the analysis carried out in this study, it was concluded that increasing the oil mobility or increasing the injection water viscosity with polymer, will improve the oil recovery. Therefore, the lower the mobility ratio (i.e the ratio of the mobility of the displacing fluid to the mobility of the displaced fluid), the more efficient the displacement, and the curve is shifted to the right. Also, the result obtained showed that, it is beneficial when the injection wells are located at the top of the reservoir structure at higher rate of injection to improve the displacement efficiency. Furthermore, the determination of the position of the water front implies that, the more water we inject into the reservoir to sweep the oil towards the producer, the more the water keeps advancing to a point it breaks through at the producer. At this stage, caution is needed to avoid viscous fingering, a phenomenal where there will be a leading edge at the front. Finally, it was recommended that a study be carried out on the rate of injection on the performance of the displacement efficiency.