Experimental study on the evaluation of surfactant/polymer flooding for enhancing oil recovery in Kumkol Oil Field

Chemical enhanced oil recovery (EOR) methods are shown to sweep the residual oil by altering physical properties of fluids after waterflooding to improve oil recovery. This work presents an experimental study on the surfactant/polymer injection for EOR in sandstone reservoirs. Interfacial tension measurements, emulsification and rheology tests are performed to select the best candidates from thirteen commercial surfactants and five commercial polymers. The performance of the preferred surfactant and polymer candidates in EOR is evaluated through a series of core flooding experiments on both homogeneous and heterogenous sand packs. Different injection schemes are investigated. The results show that the polymer injection and polymer-surfactant-mixture slug can effectively displace the residual oil as the polymer injection improves efficiency of the sweeping front. Core flooding experiments on the heterogenous sand pack show that injecting polymer in the first, followed by surfactant slug yields the better performance compared with combined polymer-surfactant-mixture injection as the polymer pre-flush improves the vertical conformance of the surfactant solution and the final recovery.