Experimental Study On Emulsification Between Crude Oil And Asp System In Three Typical Blocks Of Daqing Oilfield

Taking reservoir geology and fluid of Lamadian oilfield, Saertu oilfield and Xings hugang oilfield as experimental platform, this paper carried out the experimental study on chemicals allocation proportion after the emulsification between ASP system and c rude oil of three typical blocks, the change rule of chemicals in the produced liquid o f ASP flooding, the influence of oil composition differences on chemicals allocation pr oportion. Results showed that compared with the reservoir condition, chemicals concent ration and slug composition of Saertu oilfield and Xingshugang oilfield, connection co ndition of injection and production wells in the Lamadian oilfield was worse, the relat ive molecular mass and concentration of injected polymer was higher, otherwise, the c omposition of crude oil was different. All of these resulted in the lower chemicals co ncentration in the produced liquid. For Lamadian oilfield, the crude oil viscosity, wax content and gel content was higher, and there were many organic acid types in the ac tive components of crude oil, so the wastage of NaOH in the oil phase is higher. Mo reover, high-carbon content of n-alkanes of raffinate of the Lamadian oilfield was high er, and it was easier for heavy alkyl benzene petroleum sulfonate to dissolve in the cr ude oil, which led to the lower concentration of surfactant in the producedliquid. Afte r the emulsification between crude oil and ASP system, parts of surfactant and alkali would be dissolved in the oil phase and it was difficult for polymer to be dissolved i n the oil phase. Surfactant is dissolved in the oil phase in the way of physical mixtur e, so it also can be returned in the water phase. Alkali loss is caused by the chemica l reaction between alkali and organic acid composition, which is an irreversible proces s. Polymer can restrict the reaction between crude oil and surfactant-alkali, thus reduci ng the wastage. Flooding experiment showed that, compared with single slug, the conc entration of polymer, surfactant and alkali in the produced liquid by means of multipl e slug injection was lower, along with the interfacial tension and viscosity. Compared with polymer, the pore volume that couldn’t be swept in the core for surfactant and a lkali was smaller; therefore the retention volume of surfactant and alkali was larger w hich determined the later time for breakthrough, and there were chromatography occurr ing between surfactant, alkali and polymer.