One of the challenges indigenous microbial enhanced oil recovery (MEOR) is facing is the high percentage of divalent ions, which obstruct the growth and metabolism of microorganisms and destabilize the oil-in-water (o/w) emulsion. Six formulas were selected for the stimulation of indigenous microbes and to compare their performances on the oil emulsification and oil spreading in the Luliang oilfield containing Ca²⁺-rich brine. Illumina MiSeq sequencing of 16S rRNA genes was applied to investigate the structural response of microbial communities to various formulas. The results showed that the addition of proper organic phosphorus and the optimal P/N ratio (0.01) can facilitate production of biosurfactant and create stable o/w emulsion with specific reservoir condition containing Ca²⁺-rich brine, through direct stimulation of certain functional microbes. This study provides a promising path for direct enrichment of biosurfactant-producing and oil-degrading Dietzia genus and a potential instructional approach of indigenous MEOR in Luliang oilfield.

中文翻译：

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富含Ca2 +的中温石油储层中水生油乳液中土著微生物的营养刺激

土著微生物提高油采收率（MEOR）面临的挑战之一是高百分比的二价离子，这些离子会阻碍微生物的生长和代谢并破坏水包油（o / w）乳状液的稳定性。选择了六个公式来刺激本地微生物，并比较它们在富含Ca ^2+的盐水的吕梁油田中对油乳化和油扩散的性能。对16S rRNA基因的Illumina MiSeq测序用于研究微生物群落对各种配方的结构响应。结果表明，适当的有机磷和最佳的P / N比（0.01）的添加可以促进生物表面活性剂的生产，并在特定的含Ca ²⁺储层条件下产生稳定的o / w乳液。通过直接刺激某些功能性微生物而产生的盐水。该研究为直接富集生产生物表面活性剂和降解石油的Dietzia属提供了一条有希望的途径，并为陆良油田原产MEOR提供了潜在的教学方法。