鼠李糖脂发酵液驱油性能研究

针对鼠李糖脂在油田开发中存在的驱油体系单一和机理认识不清的问题，开展了相关的驱油机理和驱油性能研究。室内发酵出以单、双糖环鼠李糖脂为主的两种生物表面活性剂发酵液，评价了其界面性能、润湿性、洗油效率和驱油效率。研究发现，鼠李糖脂发酵液耐温抗盐性强，1%发酵液与原油间界面张力为0.2~0.5 mN/m。润湿性和洗油效率评价显示，双糖环鼠李糖脂润湿性改善更突出，洗油效率比单糖环鼠李糖脂提高15.0%，达到90.1%。分析认为，鼠李糖脂能将原油与基底间黏附功由30.3 mN/m最低降至0.059 8 mN/m（双糖环鼠李糖脂），是发酵液提高洗油效率的关键因素。驱油效率评价结果表明，双糖环鼠李糖脂发酵液在水驱效率42.16%基础上提高驱油效率12.3%，展现出较强的现场应用潜力。

Oil Displacement Performance of Rhamnolipid Fermentation Broths

In view of the unvaried nature of current oil displacement systems and uncertainty about the action of rhamnolipids in oil displacement and oil field development, the mechanisms and performance of rhamnolipids in oil displacement were investigated in the present study. Fermentation broths consisting primarily of two types of biosurfactants, viz. mono-rhamnolipids and di-rhamnolipids, were obtained via indoor fermentation, and the interfacial performance, wettability, oil washing efficiency, and oil displacement efficiency of the fermentation broths were assessed. The rhamnolipid fermentation broths were highly resistant to heat and salt, and the interfacial tensions between the 1% fermentation broths and crude oil were 0.2~0.5 mN/m. Assessments of the wettability and oil washing efficiency of the fermentation broths showed that di-rhamnolipids resulted in a greater improvement in wettability and achieved an oil washing efficiency of 90.1%, an increase of 15% compared to that of the mono-rhamnolipids. It was found that rhamnolipids could reduce the work of adhesion between crude oil and the substrate from 30.2 mN/m to a minimum of 0.059 8 mN/m (achieved with di-rhamnolipids), and that this was a key factor in the enhancement of oil washing efficiency by the fermentation broths. Assessment of oil displacement efficiency revealed that the di-rhamnolipid fermentation broth increased the oil displacement efficiency by 12.3% based on a water-oil displacement efficiency of 42.16%, thereby exhibiting great potential for field applications.