Study On Surfactants For EOR Prepared By Wastewater

Based on alkyl alcohol ether as raw material,in this paper a series of polyoxyethylene/propylene alkyl alcohol ether sulfate/phosphate surfactants with different amounts of oxyethylene/propylene chain and different lipophilic groups are synthesized by sulfamic acid/phosphorus pentoxide.The effective content of the surfactants was determined by two-phase titration and potentiometric titration.The surfactants are confirmed by ¹H nuclear magnetic resonance spectra and infrared spectra.The solubility and interfacial tension of them in 12700mg/L salinity are measured.Shorter carbon chain,more ethylene oxides?EO?and less propylene oxides?PO?lead to better solubility and higher interfacial tension.The concentration and salinity of surfactants are investigated.Petroleum sulfonate?KPS?was mixed with the surfactants.The blend system 18AS-0-9?30%?has good solubility.When the concentration is0.3%,the interfacial tension of the complex systems is 0.04 mN/m in 12700 mg/L respectively.18AS-0-9?30%?mixed with Na₂CO₃ appears ultra-low interfacial tension.In the 19071mg/L,25428mg/L and 31785mg/L,respectively,when 18AS-0-9 accounts for 35%,40%and 42%of the blend system,the blend system has good solubility,and their interfacial tension is 0.044mN/m,0.036 mN/m and 0.044 mN/m,respectively.The flooding system consists of 18AS-0-9?30%?and polymer increases the oil recovery factor by 15.2%and the APS increases the oil recovery factor by 20.3%.