Experiment Research Of Damage On Formation In Asp Flooding

ASP flooding(alkali,surfactant,polymer) is a third oil-extraction technology in recently years, it can prove oil-recovery more than 20%. At the same time, phenomenon of sediment of ions in high PH and dissolving capacity of rock are also appears, different level scale phenomenon is arisen in every experiment area. This article is concerned with mechanism analysis of scale damage and scale deposition during ASP flooding. The results of mineral-chemical reaction shows that the caustic/sandstone inter action is strong, and ASP next, surfactant and polymer have no reaction with the various minerals. The reactions between rock samples and various chemicals are the same with single mineral. The result of field scale samples analysis shows that silico-scale is the main composition. The studies on scale deposition of inorganic salts illustrate that mineral/alkali reaction engender scale-formation ions and the scale-formation ions precipitate out, then scales are formed. Reinjecting produced sewage into reservoir will cause the formation damage in ASP flooding of Daqing oilfield, so the paper studies the damage reason caused by sewage water. Used to water flooding experiment of laboratory, analyze the suspended matter,oil,alkali and polymer in the produced sewage water of ASP flooding, describe the damage mechanism of various composition on formation. The results show the suspended matter will jam pore throat, oil causes"jamin effect"which will increase oil and water flowing resistance, the physical chemistry reaction between alkali and stone and clay mineral will make formation scale, and adsorption and retention of polymer in the core decrease the reservoir permeability. So, before re-injecting, the produced sewage should be treaded to make every index qualify, which can reduce the formation damage.