Study On Emulsion Stability Of Surfactant/Polymer Flooding Produced Water In Gudao Oilfield

Surfactant/Polymer flooding technology is widely used in Shengli Oilfield, and has been improved yield of petroleum greatly. Since surface active additives were added into the oil-displacing agent, it is difficult to separate oil and water. Oil, suspended solids and HPAM increased in the treated Surfactant/Polymer flooding produced water (SPFPW). In this paper, impurities in HPAM/Surfactant flooding produced water were analysised, and the emulsion-active constituents were separated. Oil in SPFPW was separated, and then the polar chemicals were extracted. The elements and chemical groups were analysised by elemental analysis and IR spectra, Average molecular formula and Hydrophile-Lipophile Balance (HLB) of the oil fractions were calculated. Surface tension between oil solution of these polar chemicals and water were determined, and the relationships between the chemical component and emulsible ability were analysised. The influences of temperature, salinity, concentration and de-emulsifier on different constituents emulsion were researched. In order to study the emusible ability of different constituents, turbidity determination method was adopted. The interactions of different constituents were studied emphatically.The IR and elemental analysis of oils can be confirmed by these constituents molecule structure. The interface activity of F₁ was great; so the emulsion made by F₁ was stable; F₂ was rich in asphaltene and resin, and the emulsion made by F₂ was poor in stability. Acidic chemicals were contained in F₃, and the emulsion made by F₃ was greatly in emulsion strength, but the stability was poor. Emulsions made by HPAM or surfactant were great in emulsion strength and stability.The study on the interactions between different fractions showed that compounds with F₁ will cause the other fractions'coefficients bigger than 1. Coefficients of compounds with surfactant depended on the other fraction's property. Compounds with HPAM can lead to more stability of the emulsions. F₂ and salinity could inhibit the emulsion strength of the compounds.Emulsion made by F₁-treated simulation solid suspends was greatly in emulsion strength and stability. Compounds with oil fractions-treated simulation solid suspends could enhance the strength of the emulsions, especially HPAM existed; and oil fractions-treated simulation solid suspends compound with surfactant lead the emulsions to strong stability.Three demulsifiers added into the emulsions made by different fractions, the results showed that different demulsifiers act varied effects, but the problem is three demulsifier are invalid in HPAM emulsion.