| Recently energy becomes more deficient day after day. It is highly important to lower the cost of recovering oil and utilize supplemental recovery techniques to recover the oil remaining in the reservoir. Though the application of lignin and its derivatives in enhanced oil recovery (EOR) has been developed, yet they only just play the role as a sacrificial agent and co-surfactant in EOR. The interfacial tension at the crude oil-surfactant solution interface could be ultra-low only when be blended with the major surfactant, such as petroleum sulfonate. To lower the cost of surfactant flooding, a series of novel modified lignosulfonates starting from wood and straw kraft lignin, via Mannich reaction with aliphatic polyamine, acylation with aliphatic acid chloride and sulfomethylation were synthesized. The chemical identity of the product is represented by the general formula:The product from each reaction is analyzed by Kjeldahl nitrogen analysis, FT-IR spectroscopy, TLC and GC, et al. And the reaction condition is optimized after a series of experiments on the relative influential factors, such as temperature, reaction time and ratio of reactants.40 products are synthesized by the variation of modification parameters, which are the species of lignin, reaction ratios of Mannich Reaction and acylation, and the number of carbon atoms in aliphatic acyl chloride. The surface tension measurements of the product solution at different surfactant concentrations were done at room temperature, and the critical micellar concentration (CMC) values and the surface tension (γcmc) values of each product were measured. The CMC values of modified products were in a range of 2.6~4.7g/L, the corresponding surface tension (γcmc) values were 28~38mN/m.Compared with the surface tension of the unmodified lignosulfonate, the surface tension (γcmc) values of the modified lignosulfonates have reduced by 10~20mN/m. It has been known that the crosslinking between...
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