Synthesis and interfacial properties of alkylbenzene sulfonates for flooding

In surfactant flooding, surfactants added are often a mixture of the same type of molecules with different lengths of carbon chains. The relationship between a single, pure surfactant solution and crude oil is seldom studied. Additionally, up to now, alkylbenzene sulfonates are applied widely in surfactant flooding, such as Daqing oilfield, China. A factory producing alkylbenzene sulfonates will enlarge its yield to 20,000 tons per year over there. For the purposes of widening the alkylbenzene sulfonates´ application, 16 kinds of pure alkylbenzene sulfonates were synthesized through Friedel-Crafts acylation and Wolff-Kishner reduction reactions, and the compounds´ molecular structures were confirmed by 1HNMR and 13CNMR spectra. The factors affecting interfacial tension(IFT), such as, surfactant type, oil composition, electrolyte concentration, and alkali concentration were considered. The synthesized pure surfactants´ critical micelle concentration (CMC) and optimal salinity were measured through interfacial tension technique. According to lab experiments results, heavy alkylbenzene sulfonate (2SY) was synthesized in magnifying scale in Jinzhou Wash Chemical Plant and the coretests were conducted using it. The results showed that the homemade heavy alkylbenzene sulfonate(2SY) flooding can improve oil displacement efficiency 20% more than water flooding at surfactant´s concentration from 0.05%(wt) to 0.2 % (wt).