Synthesis Of A Kind Of Surfactant For EOR And Its Performance Measurement

Mainstream technology of today’s enhanced oil recovery(EOR) is alkali-surfactant-polymer flooding technology, but the adding of alkali would cause severe corrosion to reservoir formations, so it has become a hot issue in today’s EOR technology research to develop a new type of surfactant for EOR which has no dependence on basic compounds. Alcohol polyoxyethylene ether sulfonate(AESO) is a kind of nonionic-anionic surfactant which combines the advantages of both nonionic and anionic surfactant. As a theoretically ideal surfactant for EOR, it maintains superiority in salt resistance, high valent cation resistance and temperature stability. However, the final yields of various types of synthetic methods are undesirable, so AESO has not been widely used.In this dissertation, AESO was synthesized using fatty alcohols, ethylene oxide, thionyl chloride and potassium sulfite as raw materials in three steps including anionic polymerization, chlorination and sulfonation reaction. On the basis of reported references, the reaction conditions of each step were also improved and optimized through single factor experiment. The optimal conditions of each reaction were confirmed depending on the experimental data:(1) In anionic polymerization reaction:the molar ratio1:4(fatty alcohols:ethylene oxide), the reaction temperature and pressure115～125℃,0.4MPa, the catalyst sodium hydroxide in an amount of0.1%mass of fatty alcohols, intermittent injection of ethylene oxide, yielding to44.2%;(2) In chlorination reaction:pyridine as the catalyst, thionyl chloride as the chlorinated agent, the molar ratio1:1.6:0.8(alcohol polyoxyethylene ether:thionyl chloride:pyridine), the reaction temperature70℃, the reaction time10h, yielding to92.4%;(3) In sulfonation reaction:water as the solvent in an amount of20%mass of halid, n-hexanol as the diluent in an amount of20%mass of halid, potassium sulfite as the sulfonating agent, the molar ratio1.5:1(potassium sulfite:halid), reaction temperature and pressure155℃,1.0MPa, reaction time6h, yielding to91.3%. The products of each step were characterized by IR,13C-NMR, GC-MS and ESI-MS.The surface activity, salt resistence, high valent cation resistance, temperature stability and PH stability of A12ESO were measured, and the outcome seemed to be inspiring. When compounded with polyacrylamide, A12ESO can reduce the oil-water interfacial tension to7.46×10-3mN/m.