以石油烃为唯一碳源微生物采油现场试验研究

Application of microorganisms using petroleum hydrocarbon as the sole carbon source to the MEOR field test

利用以石油烃为唯一碳源的微生物菌种短短芽孢杆菌HT和蜡状芽孢杆菌HP,在大庆油田朝阳沟低渗透油藏进行了微生物采油矿场试验.采用生化分析方法和手段,对室内及现场试验进行了评价、监测.结果表明,所筛选的微生物能够较好地在油层条件下生长、繁殖,通过降解重质石油烃使原油粘度由作用前101 mPa.s降低到作用后56.9 mPa.s,降低43.7%,含蜡量平均下降32.6%,含胶量平均下降为31%,微生物产生的脂肪酸等活性物质能有效降低油水间界面张力;通过气相色谱分析,发现原油中烷烃组分发生变化,正构烷烃碳数分布曲线向轻组份方向移动.现场试验结果表明,该微生物采油方法能够有效地提高低渗透油层的原油采收率,增加原油产量,降低含水率.

The bacteria of HT and HP which use petroleum hydrocarbon as the sole carbon source are applied to MEOR field test in Chaoyanggou reservoir characterized by its low permeability. The dynamic of the laboratory experiment and field test is evaluated and monitored through a series of bio-chemical analyses. The study demonstrates that the microorganisms can grow and propagate well under the reservoir condition and they can degrade the heavy petroleum hydrocarbon in the crude oil, resulting in a decrease of oil viscosity by 43.7% , from 101 mPa·s to 56. 9 mPa·s. At the same time, the average content of paraffin and resin is reduced by 32. 6% and 31% respectively. The active components such as fatty acids produced by the action of oil degradation can reduce the IFT （interfacial tension） between the crude oil and water effectively. The GC-MS analysis also shows a declination of heavy normal alkane in the degraded oil. So, MEOR may be an effective method to increase oil production and reduce water cut in the reservoir with low permeability.