Synthesis Of Cation-nonionic Surfactants And Evaluation Of Oil Displacement Performance

Sulfonate anionic-nonionic surfactants have better chemical stability due to the connection of C and S by covalent bonds in the molecular,and the sulfonate have better salt resistance than other anionic surfactants.They can be used as flooding agent in high temperature and high salinity reservoir.Alkyl alcohol/phenol polyoxyethylene ether sulfonate were synthesized and evaluated in this paper,the main experiment results are listed as follows:?1?Sodium alcohol was synthesized by alkyl alcohol/phenol polyoxyethylene ether and NaOH or CH3ONa reacting.Alkyl alcohol/phenol polyoxyethylene ether sulfonate with different EO chain and hydrophobic groups were synthesized by alcohol sodium and 2-chloroethyl sulfonate reacting.Etherification reaction of A-7 optimized by single-factor.The structure of products were verified by IR,1H-NMR,13C-NMR,MS and so on,consistent with target molecule.?2?The critical micelle concentration?cmc?value and ?cmc of linear alkyl alcohol polyether sulfonate increased with the increasing of EO chain.The cmc value of branched T-7 was larger than that of linear A-7 with the same hydrophilic groups,and the ?cmc of P-7 was higher than that of A-7.A-7,A-9,A-15 and T-7 had no new phase in NaCl 22×104mg/Lsolution,and alkyl alcohol/phenol polyoxyethylene sulfonate weren't precipitated in Ca²⁺3 000mg/L solution.?3?The interfacial tension?IFT?of linear alkyl alcohol polyether sulfonate solution and crude oil first increased and then decreased with increasing of EO chain in the molecule at 85 ?.The IFT of A-7 and T-7 was lower than that of P-7.The IFT of A-7,A-9 and T-7 system was 10-3?10-4mN/m in NaCl 10-22×10-4mg/L solution.The IFT of the system first decreased and then increased with increasing of Ca²⁺ content in solution.The IFT of preferable system T-7,A-7 and A-9 kept 10-2 mN/m after aging 90 days at 85 ? and 110?.?4?The T-7,A-7 and A-9 had better ability to reduce IFT of surfactants solution and crude oil?DK/YM?with more asphaltene and suitable carbon number distribution.For linear A-7,adding resins or asphaltenes into kerosene can reduce IFT because of synergism of crude oil fractions and A-7.On the contrary,for branched T-7,the IFT increased.Adding saturates or aromatics into kerosene resulted in increasing IFT of A-7/T-7 system.?5?The emulsification rate of P-7 was fastest,and the emulsification stability of P-7 and T-7 were better than that of A-7 system at the same oil and water volume ratio.The droplet size of P-7 emulsion was smaller and concentrated distribution,and the medium diameter was 20.61um.After soaking with A-7,P-7 or T-7 solution,the hydrophilic quartz plate was still hydrophilic,and the lipophilic quartz plate became hydrophilic.The absorption loss of T-7 and P-7 were less than lmg/g.?6?Core flooding experiments showed that the enhanced oil recovery of the system with lower IFT was higher at the core permeability about 10×10-3um².The enhanced oil recovery of T-7,A-7 and P-7 were about 17%at the core permeability about 50×10-3um²,and the emulsifying ability of P-7 contributed to enhance oil recovery.