异化铁还原菌原位合成铁氧类纳米颗粒及其提高原油采收率的研究进展

Research progress on in situ synthesis of iron-oxide nanoparticles by dissimilatory iron-reducing bacteria for enhanced oil recovery

摘要:

基于微生物矿化机制，异化铁还原菌原位合成纳米材料技术近年来在油藏提高采收率中展现出良好的效果，逐渐成为微生物提高采收率研究的重要方向。本文从油藏中异化铁还原菌的生态多样性与储层沉积环境的适应性出发，梳理了其原位合成铁氧类纳米颗粒的成核机制以及在提高原油采收率过程中的作用。异化铁还原菌可通过胞内控制矿化和胞外诱导矿化2种机制生成铁氧类纳米颗粒，前者依赖酶促反应与模板调控，后者则通过胞外电子传递与胞外聚合物协同诱导金属离子沉淀。研究表明，异化铁还原菌合成的纳米颗粒因其自身具有高比表面积、润湿反转等能力，可在无其他生物代谢产物协同作用的情况下，降低油-水界面张力并增强乳化作用，提高驱油效率。室内物理模拟实验显示，该技术在低渗透与非均质油藏中采收率提高10%-15%。相较于传统外源注入纳米材料的方式，异化铁还原菌原位合成纳米颗粒的方式在实验条件下表现出更优良的分散性与界面调控能力，而且在特定环境下可实现持续产物供应。但这种方法在实际的油藏环境中的应用可行性仍需进一步研究验证。

Abstract:

On the basis of microbial mineralization mechanisms, the in situ synthesis of nanomaterials by dissimilatory iron-reducing bacteria has demonstrated promising efficacy in enhanced oil recovery (EOR)—specifically microbial enhanced oil recovery (MEOR)—applications in recent years, and has gradually become a key focus of the research on MEOR. This paper, beginning with an analysis of the ecological diversity of dissimilatory iron-reducing bacteria within reservoirs and their adaptability to depositional environments, systematically reviews the nucleation mechanisms by which these organisms generate iron-oxide nanoparticles in situ and elucidates their roles in improving crude oil recovery. Dissimilatory iron-reducing bacteria produce iron-oxide nanoparticles via two distinct pathways: intracellularly controlled mineralization and extracellular induced mineralization. The former relies on enzyme-mediated reactions coupled with biomolecular template regulation, while the latter proceeds through extracellular electron transfer (EET) and coordination with extracellular polymeric substances (EPS) to precipitate metal ions. Studies indicate that nanoparticles biosynthesized by dissimilatory iron-reducing bacteria, owing to their inherently high specific surface area and wettability-reversal capabilities, are able to reduce oil-water interfacial tension and enhance emulsification, thereby improving oil displacement efficiency even in the absence of other microbial metabolic byproducts. Laboratory physical-model experiments have demonstrated that this biogenic nanoparticle-based EOR technique can boost recovery by 10%-15% in low-permeability and heterogeneous reservoir analogues. Compared with conventional approaches that rely on exogenous injection of pre-formed nanoparticles, the in situ biosynthesis route exhibits superior nanoparticle dispersion and interfacial modulation under experimental conditions, and offers the potential for sustained product generation in favorable reservoir niches. Nonetheless, the practical applicability and scalability of this strategy under true reservoir conditions remain to be fully validated through further field-scale studies and pilot tests.