本源微生物驱油机理研究及现场应用

Mechanism of indigenous microbial enhancement of oil recovery and pilot test

对大港油田本源微生物驱现场试验过程中流体的微生物学特征、地球化学特征及生产动态进行了监测 ,研究了本源微生物提高原油采收率的机理。随注入水一同注入大量含氮、含磷盐的物质及空气 ,使生态系统中的微生物和理化特征发生了显著变化。地层水中嗜热微生物的数量和活性分别增加了 10 3 ～ 10 5倍和 10～ 10 3 倍。烃氧化菌的激活导致了注入水在近井地带原油的氧化及低分子脂肪酸含量增加。原油的生物转化产物刺激了发酵菌、硫酸盐还原菌及产甲烷菌的生长 ,微生物的代谢产物有利于原油的采出。从生产动态分析可以看出 ,经生物技术处理后 ,83 %的生产井见到了效果 ,3年共增油 8874t ,投入产出比达到 1∶5 2。

Microbiological, geochemical and production characteristics of the formation liquid in Dagang Oilfield were monitored during the microorganism flooding test for investigating the microbial enhancement of oil recovery mechanism. Formation water samples were acquired before and after biotechnological treatment. A large amount of nitrogen and phosphorous salt and air were injected together with water into formation, which resulted in significant changes in the microbiological and physicochemical characteristics of the ecosystem. The cell number and activity of all thermophilic microorganisms in the formation water increased by 103 to 105 and 10 to 103 times respectively. The activity of oil-oxidizing bacteria led to increment of oil biotransformation and accumulation of lower fatty acid. The products of oil biotransformation stimulated the growth of fermentative, sulfate-reducing and methanogenic bacteria. The products of microbial metabolism are available for the enhancement of oil recovery. The good effects can be seen in 83% of oil production wells after biotechnological treatment. The input-output ratio is 1 to 5.2.