Conformance Control Treatments for Water and Chemical Flooding: Opportunity and Risk Evaluation

Abstract

Abstract The volumetric sweep efficiency is an essential factor in the success of any water flooding or EOR project. Volumetric sweep efficiency (VSE) is controlled by the local reservoir geological settings, well patterns and completion design and production and injection strategies. In this paper we present a numerical modeling methodology to quantify VSE for different well patterns and geological settings independent of fluid types and saturation. The impact of conformance control techniques on VSE is estimated and the results translated to ultimate oil recovery for different driving mechanisms through standard analytical approximations. The methodology is used to evaluate the impact of conformance control techniques during water and polymer flooding for medium to high viscous oil reservoir. The results show that unselective blocking of high permeable layers during water flooding of high viscous oil reservoirs can be counterproductive and narrows the scope of potential chemical EOR opportunities. Polymer-(like) flooding wherever applicable is found to be in itself a very efficient conformance technique to increase the overall sweep efficiency for geological heterogeneities. In general abnormal high conductive features and long induced fractures tend to lower the efficiency of water or chemical flooding and cause excessive water/chemicals production to the surface facilities. Near wellbore mechanical treatments are then effective to minimize polymer production and increase oil production of which examples from ongoing polymer project will be discussed.