烃降解型微生物强化水驱提高原油采收率微观机制研究

Study on Microcosmic Mechanism of Microbial Enhanced Oil Recovery by Hydrocarbon Oxidizing Bacteria

借助微观透明模型建立微观模拟驱油试验系统。以烃降解菌株Rhodococcus ruber Z25和Bacillus cereus Z31为出发菌株,通过物理模拟驱油实验考察了多孔介质中水驱原油的特点及残余油的分布形式:残余油主要以油条和油珠的形式滞留于孔隙介质中;以油膜形式附着在骨架表面;在喉道转角处水流速度为零的"驻点"部位。通过静置培养观察了多孔介质中水驱后油藏微生物降解原油及微生物富集的状态,微生物由单菌体形成油水界面处的菌胶团结构。通过研究后续水驱作用下残余油的驱替特征表明,微生物菌胶团、松散的油相与驱替液水相彼此裹挟,沿驱替压力方向运移。本研究揭示了烃降解微生物驱油的微观机制,为微生物采油从实验室走向矿场实践奠定了理论基础。

In this paper, a microcosmic physical simulation system was established by transparent micro-model to study the mechanisms of Microbial Enhanced Oil Recovery （MEOR）. Two hydrocarbon oxidizing strains （Rhodococcus ruber Z25 and Bacillus cereus Z31） were employed. The rules of water-flooding process and distribution of residual crude oil were obtained by water-flooding experiment. The main residual oil located in the surface and the blind zones of porous media in the form of constant oil phase. After the cultivation of the microorganisms, zoogloea was observed in the interface between aqueous and oil phase. The residual oil was incised into pieces and the structure of the oil was totally destroyed. Therefore, the post water-flooding had performed efficiently in displacing the residual oil due to the metabolic activities of the microorganisms. The main effects on EOR process and the oildisplacing mechanisms by hydrocarbon oxidizing bacteria were studied, which would contribute to the potential application of MEOR in the pilot test.