The Research On Non-fluorocarbon Cleanup Additive Of Fracturing Fluid

The cleanup additives of fracturing fluid are often made of surfactants.Though the fluorine-containing surfactants have the performance of anti-temperature and low surface tension,they are usually costly and contaminative.Therefore,the surfactants with hydrocarbon chains still have the prospect of application.The mechanism and characteristic of the cleanup additives were discussed.The surface tensions,the oil-water interfacial tensions of the cleanup additives were measured.The contact angles on the surface of the sands and the compatibility of the cleanup additives and the fracturing fluids were also tested.According to the mixturing theory of the anionic/cationic surfactants,the surfactants were optimized.AES as solubilizer could increase the solubility of anionic/cationic surfactant complexes and surfacial activity of the mixtures.Then,two formulas of the cleanup additives were chosen.A:12%(ABS+LP)+8%AES+25%solvent+55%waterB:14%(K-12+OS)+6%AES+25%solvent+55%waterThe surface tension of A with 1‰aqueous solution is 26.4 mN/m and the interfacial tension with kerosene is 1.2 mN/m.And the surface tension of B with 1‰aqueous solution is 26.4 mN/m and the interfacial tension with kerosene is 25.0 mN/m,and the interracial tension with kerosene is 1.3 mN/m.Though its capability of lowering the surface tension is very strong,B could result in serious emusication between the crude oil and gel-breaking fluid,which leads to less efficiency of emulsion-breaking and of cleaning up.A with the dosage of 0.5‰,the liability of the emulsification is less.The demulsification rate is 99%after 4h at the temperature of 60℃.The surface tension of the gel-breaking fluid containing A is below 28 mN/m.Finally,the cleanup rate of 90.1%is obtained,which is about the result of the fluorine-containing cleanup additive F.