Experimental investigation of CO2, - miscible oil recovery at different conditions

Abstract

In miscible flooding, the incremental oil recovery is obtained by one of three mechanisms. These mechanisms are oil displacement by solvent through the generation of miscibility, oil swelling, and reduction in oil viscocity. To evaluate the performance of miscible CO2 flooding, extensive laboratory tests were condected on 2 and 4 ft long sandstone cores using low nd high salinity brine solutions as aqueous phase and three different oleic phases (n-Decane, light, and medium Saudi crude oils). Injection scheme (Continuous Gas Injection "GGI" versus Water Alternating Gas "WAG"). WAG ratio, slug size, oil types, core orientation and core lenght were investigated. In addition, miscible WAG flooding as a secondary process was investigated and its efficiency was compared tot he conventional tertiary miscible gas flooding.