Rellegadla Sandeep, Prajapat Ganshyam, Jain Shikha, Agrawal Akhil
Energy and Environment Research Laboratory, Department of Microbiology, Central University of Rajasthan, NH-8, Bandersindri, Kishangarh, Ajmer, Rajasthan, 305817, India.
Centre for Water Technology, Department of Biological and Chemical Engineering, Aarhus University, Universitetsbyen 36, 8000, Aarhus C, Denmark.
Appl Microbiol Biotechnol. 2023 Sep;107(17):5531-5544. doi: 10.1007/s00253-023-12673-3. Epub 2023 Jul 10.
The role of indigenous microbial communities in residual oil extraction following a recovery process is not well understood. This study investigated the dynamics of resident microbial communities in oil-field simulating sand pack bioreactors after the polymer flooding stage resumed with waterflooding and explored their contribution to the oil extraction process. The microbial community succession was studied through high-throughput sequencing of 16S rRNA genes. The results revealed alternating dominance of minority populations, including Dietzia sps., Acinetobacter sps., Soehngenia sps., and Paracoccus sps., in each bioreactor following the flooding process. Additionally, the post-polymer waterflooding stage led to higher oil recovery, with hydroxyethylcellulose, tragacanth gum, and partially hydrolyzed polyacrylamide polymer-treated bioreactors yielding additional recovery of 4.36%, 5.39%, and 3.90% residual oil in place, respectively. The dominant microbial communities were previously reported to synthesize biosurfactants and emulsifiers, as well as degrade and utilize hydrocarbons, indicating their role in aiding the recovery process. However, the correlation analysis of the most abundant taxa showed that some species were more positively correlated with the oil recovery process, while others acted as competitors for the carbon source. The study also found that higher biomass favored the plugging of high permeability zones in the reservoir, facilitating the dislodging of crude oil in new channels. In conclusion, this study suggests that microbial populations significantly shift upon polymer treatment and contribute synergistically to the oil recovery process depending on the characteristics of the polymers injected. KEY POINTS: • Post-polymer flooded microbial ecology shows unique indigenous microbial consortia. • Injected polymers are observed to act as enrichment substrates by resident communities. • The first study to show successive oil recovery stage post-polymer flood without external influence.
在采收过程之后，原生微生物群落对残余油开采的作用尚未得到充分理解。本研究调查了聚合物驱油阶段后恢复水驱的油田模拟砂柱生物反应器中常驻微生物群落的动态变化，并探讨了它们对原油开采过程的贡献。通过对16S rRNA基因进行高通量测序研究了微生物群落演替情况。结果显示，在注水过程之后，每个生物反应器中少数种群交替占据主导地位，包括Dietzia菌属、不动杆菌属、索氏菌属和副球菌属。此外，聚合物驱后水驱阶段提高了原油采收率，经羟乙基纤维素、黄芪胶和部分水解聚丙烯酰胺聚合物处理的生物反应器原地残余油额外采收率分别为4.36%、5.39%和3.90%。先前报道称，占主导地位的微生物群落能够合成生物表面活性剂和乳化剂，以及降解和利用碳氢化合物，这表明它们在辅助采收过程中发挥了作用。然而，对最丰富分类群的相关性分析表明，一些物种与原油采收过程呈正相关，而另一些则作为碳源竞争者。该研究还发现，较高的生物量有利于封堵储层中的高渗透带，促进原油在新通道中的驱替。总之，本研究表明，聚合物处理后微生物种群发生显著变化，并根据注入聚合物的特性对原油采收过程产生协同作用。要点：• 聚合物驱后微生物生态学显示出独特的原生微生物群落。• 观察到注入的聚合物被常驻群落用作富集底物。• 首次研究表明在无外部影响的情况下聚合物驱后存在连续的原油采收阶段。
