Preparation And Performance Evaluation Of P20 Supramolecular Surfactant

At present,in the practical application of EOR methods in binary and ternary composite flooding,there are practical problems such as poor resistance of surfactants to divalent ions and high formation adsorption loss of surfactants.To comprehensively analyze the above problems,it is necessary to prepare a surfactant,which can not only reduce the loss of surfactant,but also improve the utilization of surfactant and the effect of oil displacement agent.Cationic polyelectrolyte and anionic surfactant were screened according to molecular chain length and electrostatic attractiveness.Polydimethyldiallyl ammonium chloride with molecular weight of 200,000 was selected as cationic polyelectrolyte and sodium dodecylbenzene sulfonate with low price was selected as anionic surfactant.The reaction temperature,pH value and reactant proportion were screened according to the effect of self-assembly among macromolecules.The reaction temperature range was 25.0 ~45.0 ~C,the reaction pH value was 7~9,and the optimum reactant ratio was 1:1.65.The change of characteristic peaks was observed by infrared spectroscopy,and the formation of effective substances was observed by laser particle size analysis.The median particle size of the formed substances was about 0.5 um.The structure and morphology of the substances were observed by transmission electron microscopy.According to the variation of surface tension and oil-water interfacial tension,the critical micelle concentration was determined to be about 0.2% of the mass concentration.Static adsorption experiments and dynamic adsorption experiments were carried out.The results showed that the supramolecular surfactants had strong anti-adsorption performance and could effectively reduce the consumption of surfactants by rocks.It was observed that the early adsorption of P20 supramolecular surfactants was stronger during the adsorption process.The dynamic adsorption capacity is lower than the static adsorption capacity,and the adsorption capacity increases more when the mass concentration exceeds 0.4%,so the mass concentration is determined to be less than 0.4%.Non-ionic protectors can effectively inhibit the influence of divalent ions on the properties of surfactants and reduce their interfacial tension.In the emulsion formed by P20 supramolecular surfactant and crude oil,water precipitated quickly in the early stage of the emulsion,and the emulsion was completely separated after 120 hours.The emulsifying performance of P20 supramolecular surfactant was better.Laboratory displacement experiments show that the optimum concentration is 0.2wt%.The optimum injection rate was 0.3PV.In this paper,a kind of surfactant with anti-adsorption characteristics was studied.