THE IMPACT OF HETEROGENEITY EFFECT ON WATER

Abstract

Waterflooding is one of the cheapest oil recovery methods and the most popular secondary method to increase oil recovery by injecting water into the reservoir. This study aim to examine the effect degree of heterogeneity on the main forces that governing the water flooding performance in stratified reservoirs. These forces such as capillary Forces which arise when water is injected into a layered reservoir, movement of the flood front are more rapid in the more permeable layers.  The different flood front positions create sharp saturation gradients between layers. The second important force is the viscous forces, due to similar viscosities between the displacing and the displaced phase, the injection front advances almost as a piston. This means that in general a large fraction of the porous medium was perfectly swept by water and only residual oil is left behind in a microscopic from as isolated ganglia. Last but not least gravity force, when water displaces oil linearly in an inclined, it is necessary to include the contribution of gravity forces to the fractional-flow, because the oil density is less than the water density, gravity forces reduce the fractional flow of water when water is moving updip.This work is being conducted to study the Water flooding performance of layered reservoirs with permeability variation in vertical direction being characterized by log-normal distribution function with cross flow between layers. The permeability distribution function is defined by controlling the degree of variation by setting  the Dykstra-Parsons (DP) variation coefficient VDP and the standard deviation of the distribution σk. The study indicates that performance of the water flooding is getting worse as the degree of heterogeneity increased and the contrast in permeability between the adjacent layers become bigger.