复合驱油菌株提高安塞低渗透油田采收率实验

Laboratory on Enhancing Oil Recovery of Ansai Low-Permeability Reservoir by Microbial Combination Flooding Process

从安塞油藏环境中分离到两种高产生物表面活性剂的优良驱油菌株,经鉴定为铜绿假单胞菌DN001和枯草芽孢杆菌DN002.通过室内和现场试验评价了驱油微生物及其复合菌株降低表面张力和界面张力的能力、对原油的乳化性能以及对当地油藏的环境适应性。结果表明,复合菌株发酵液可将水的表面张力从72 m N/m降低到25.1 m N/m,并且发酵液的油水界面活性较高,平衡界面张力为0.954 3 m N/m.筛选的微生物菌体在安塞油田油藏环境中可大量繁殖。室内驱油模拟实验表明,经复合微生物驱替作用后,采收率可提高17.38%,说明筛选的菌株驱油性能较强,微生物驱油室内评价结果为其在安塞油藏现场应用提供了可靠的试验依据。

Two strains of bacteria with good oil displacement effect as a bio-surfactant were isolated from Ansai low-permeability reservoir,which were identified as Pseudomonas aeruginosa DN001 and Bacillus subtilis DN002.The ability of reducing the surface tension and interfacial tension,emulsion performance of crude oil and environmental adaptability for the two microbes were evaluated in experiment.The results show that the fermented liquid of the combination bacteria strains can reduce the surface tension of water from 72 to 25.1 mN/m and has high oil-water interfacial activity with the equilibrium interfacial tension of 0.954 3 mN/m.The screened microbial bacteria can thrive in Ansai reservoir environment.The core displacement experiment indicates that microbial combination flooding can improve recovery by 17.38％.These results show that the screened strains have a good performance in enhance oil recovery and provide a reliable experimental basis for the field application in Ansai reservoir.