Synthesis Of Poly-alkylbenzene Sulfonates Used For Oil Displacement

Alkylbenzene sulfonates are the main surfactants for tertiary recovery. Sulfonate surfacetants have the ability to lower the interfacial tension of oil and water, so that they can improve oil recovery. Sulfonate surfacetants'low cost and wide resources make them play an important role in enhanced oil recovery.Longer chain inner olefins were synthesized by C9~C12 branched olefins with a coordinated AlCl3 as catalyst in this paper. Polyalkylbenzene sulfonates were synthesized by the longer chain inner olefins and linearα-olefins through alkylation, sulfonation and neutralization. The main act-ive component of the polyalkylbenzene sulfonates were 48%-52% used two phase titration analysis.The results show that linear hexadecylxylene and branched octadecylxylene sulfonates at concentration < 0.3% can decrease the interfaceial tension of Daqing Sichang crude oil/reservoir water to ultralow(10-3mN/m) in the presence of NaOH at 0.2%～1.2% mass percentage scopes. The mass percentage concentrations of NaHCO3 at 0.75%～1.25%, the two sulfonates can decrease the interfaceial tension of the oil/ water to 10-4mN/m ultralow. Under test conditions the static adsorbance of linear hexadecylxylene and branched octadecylxylene sulfonates were 1.4 mg/g and1.6mg/g respectively. By using polyalkylbenzene sulfonates of average equivalent 430, NaOH and polyacrylamide ASP flooding system, the physical simulation flooding experiments in natural cores and man-made cores showed that the oil recovery reached over 20%.