微生物及其代谢物提高低渗透油藏渗吸采收率

Microorganisms and Their Metabolites Enhancing Imbibition Recovery of Low Permeability Reservoirs

付 健 刘宇龙 张岑茜 王晨月 孙珊珊 佘跃惠 张 凡

FU Jian LIU Yulong ZHANG Cenqian WANG Chenyue SUN Shanshan SHE Yuehui ZHANG Fan

自发渗吸是低渗透油藏采油的重要方法，微生物提高渗吸采收率的主要采油机理详细研究报导较少。使 用从油藏环境中分离得到的专利菌株波茨坦短芽孢杆菌BS3096和铜绿假单胞菌LZ3-2，通过自发渗吸实验研究 了细菌和培养基的选择、微生物的生长条件、细菌的代谢产物生物表面活性剂、菌体影响等因素对微生物提高采 收率的影响。研究结果表明，含有脂肽生物表面活性剂的渗吸液可以使油水界面张力从0.8848 mN/m降低至 0.2055 mN/m，接触角由116.4°减小至42.8°，使岩石的润湿性从油湿变为水湿。油水界面张力的降低和岩石润湿 性的改变对提高渗吸原油采收率影响显著，BS3096产的脂肽生物表面活性剂渗吸采收率可达60%；铜绿假单胞 菌PAO1产的鼠李糖脂渗吸采收率为56.26%；LZ3-2产的糖蛋白类生物乳化剂对原油的具有乳化效果，乳化率为 6.96%。渗吸实验中，BS3096菌体在岩心内大量累积，选择性地封堵大孔喉通道，使渗吸液分流至低渗区的小孔 隙中将原油驱替出来，可使采收率提高7.5百分点。在相同的实验条件和表面活性剂浓度下，生物表面活性剂和 化学表面活性剂自发渗吸作用强弱顺序为生物型＞阴离子型＞非离子型＞阳离子型，脂肽生物表面活性剂的渗 吸采收率比化学型表面活性剂高11.8百分点～41.5百分点。本研究为低渗透油藏提供了一种高效经济且环境 友好的提高原油采收率的方法，为微生物及其代谢产物在现场的应用提供了理论支持。

Spontaneous imbibition is an important method for oil recovery in low permeability reservoirs. There are few reports on the main oil recovery mechanism of microbial enhanced imbibition recovery. In this paper，the patented strains of Brevibacillus potsdamus BS3096 and Pseudomonas aeruginosa LZ3-2 isolated from the reservoir environment in the laboratory were used. Through spontaneous imbibition experiments，the selection of bacteria and medium，the growth conditions of microorganisms，the metabolites of bacteria biosurfactants，the effects of bacteria and other factors on microbial enhanced oil recovery were studied. The experimental results showed that the imbibition fluid containing lipopeptide biosurfactant produced by BS3096 could reduce the oil-water interfacial tension from 0.8848 to 0.2055 mN/m，and the contact angle from 116.4° to 42.8°，so that the wettability of the rock changed from oil wet to water wet. The decrease of oil-water interfacial tension and the change of rock wettability had a significant effect on the recovery of imbibition crude oil. The imbibition recovery of lipopeptide biosurfactant produced by BS3096 could reach up to 60%. The recovery rate of rhamnolipid produced by Pseudomonas aeruginosa PAO1 was 56.26%. The glycoprotein bio-emulsifier produced by LZ3-2 had emulsifying effect on crude oil，and the emulsification rate was 6.96 %. In the imbibition experiment，BS3096 bacteria accumulated in the core，selectively blocked the large pore throat channel，and diverted the imbibition fluid to the small pores in the low permeability area to displace the crude oil，which could increase the recovery rate by 7.5 percentage point. Under the same experimental conditions and surfactant concentration，the order of spontaneous imbibition of biosurfactants and chemical surfactants was biotype ＞ anion ＞ nonionic ＞ cation. The imbibition recovery of lipopeptide biosurfactants was 11.8—44 percentage point higher than that of chemical surfactants. This study provides an efficient，economical and environmentally friendly method for improving oil recovery in low permeability reservoirs，and provides theoretical support for the application of microorganisms and their metabolites in the field.

10.19346/j.cnki.1000-4092.2024.02.016