用中和烃氧化产物制备高界面活性的驱油剂

为了用C_(22)和C_(26)直链和环烷烃的石油馏分油作原料制备适用于强化采油的活性剂,先将原料汽相氧化,再用碱液中和氧化产物。用红外光谱研究了氧化产物和中和产物的组成,发现前者含有羧酸,后者含有羧酸盐。得到的羧酸盐活性剂用于模拟油[由38.8%(体积)的异丙苯和61.2%(体积)的正癸烷组成],使油水间达到低于10~(-2)mN/cm的超低界面张力。实验表明,用氢氧化钠进行中和,比用其他的碱性物质(如硅酸钠、三聚磷酸钠、碳酸钠)更易得到界面活性高的活性剂溶液;当硅酸钠或三聚磷酸钠协同氢氧化钠一起与氧化产物反应时,所得活性剂的界面张力对电解质浓度的敏感程度比仅用氢氧化钠作处理剂时低,中和时的碱量会影响所得活性剂体系的界面张力。对于活性剂浓度不同的体系,若pH值相同则最佳含盐量也相同;若pH值高,则最佳含盐量低。当活性剂体系含有1000ppm的氯化钙时,仍具有良好的界面活性。在驱油试验中,浓度为1%的1个孔隙体积的活性剂溶液可采出42%的二次残油。

Preparing of Ultralow Oil-water IFTs Surfactants by Using Neutralized Oxidized Hydrocarbons

Surfactants that may be suitable for application in enhanced oil recovery have been produced from C_(22) and C_(26) paraffinic and naphthenic petroleum fractions by a two-step process. The hydrocarbon feed stocks were first oxidized in the vapor-phase, followed by neutralization of the oxidized products with aqueous alkali. Infrared spectroscopy was used to identify the functional groups present in the oxidized products and the products after neutralization. The spectra indicated the presence of the carboxylic acid and sodium carboxylate respectively. As a result, dilute solutions of organic acid salts were produced that achieved ultralow ( <10~(-2)dyne / cm) interfacial tensions against a synthetic oil. Surfacant solutions that exhibited the lowest interfacial tensions (IFTs) were prepared from neutralizations that used low concentrations of sodium hydroxide rather than sodium silicate, sodium tripolyphosphate, or sodium carbonate. Neutralizations that used sodium silicate or sodium carbonate resulted in surfactant solutions having IFT profiles that were less sensitive to the electrolyte concentration. When sodium hydroxide was combined with either sodium silicate or sodium tripolyphosphate in the neutralizations, solutions having intermediate IFT properties were produced. The amoumt of alkali used in the neutralizations was observed to affect the IFT properties of the resultant surfactant solution. The electrolyte concentration at which the minimum IFT occurred was inversely related to the pH of the Surfactant solution. For surfactant solutions of common pH prepared from different concentrations of oxidized product, the minimum IFT all occurred at the same concentration of electrolyte. Surfactant solutions remained interfacially active even in the presence of significant concentration of calcium chloride. One pore voiume of a solution containing only about 1% of active surfactant recovered 42.0% of the residual oil in a tertiary core-flood experiment.