Study The Formulation Of Alkaline/Surfactant/Polymer Flooding System For The Gaotaizi Second Reservoir

Alkaline/surfactant/polymer(ASP) flooding system is appear at the 80's as one newmethod of EOR. The essential of the method: it uses alkaline,the price is cheap, partly orentirely substitute surfactant, the price is expensive, to decrease the surfactant be used inchemical flooding. In addition, the join of Alkaline also can reduce the loss of surfactant andpolymer which be adsorbed and retained. Alkaline reacted with the organic acid component ofthe oil to bear oil acid soap. The synergism of the oil acid soap and the join's surfactant: thesynergism of the alkaline and the surfactant and the fluid mobility cortrol of the polymer, theabove three factor not only improving oil recovery, but also enhance the swept volume.The following several aspects are further studed in this paper:Through laboratoryexperiment, this paper studies the interfacial tension of oil and ASP compound system,discusses the effecting factors of interfacial tension in ASP flooding, maked the curve chart ofinterfacial tension, discusses the relationship of all kinds of chemical and interfacialtension.Through study the effect of combined surfactant on the interfacial tension, analyze thesynergism of combined system, researches the stability of compound system and select thesystem which can keep ultra low interfacial tension for a long time. The absorption of surfactantis studed, and finds efficiency method for reduce absorption . The estimate study of oildisplacement effect of ASP flood, through the laboratory physical simulation experiment anddigital analogy, it discusses the effect of the chemical consistence and the size of slug on the oildisplacement effect of the system, selects the final injection manner and the size of slug.Through study, conclusions can be drawn as follows: the ASP combination floodingformula for second oil reservoir is Alkali (A)1.2%+ the combined Surfactant(S)0.2%+Polymer(P) 1300mg/L, When the surfactant consistence range from 0.05% to 0.3%,thealkaline consisitence range from 0.6% to 1.2%, the system can form ultra low tension whichcan improving oil recovery in a big amplitude. The system stability is good, when it is laidaside three months, interfacial tension generally not changes, the compatibility is stronger, thecombined surfactant system have the good synergism, in the alkyl sulfonate and its combinedsystems with petroleum carboxylate, petroleum carboxylat of compound surfactant play thesacrificial agent role.have reduce the loss of main surfactant alkyl sulfonate, lows thecost.According the laboratory physical simulation experiment and digital analogy, determinesthe ASP formula, injection process and slug size in the pilot test.