油藏注入水靶向脱硫潜力的高温脱硫菌群富集驯化

Enrichment and acclimation of thermophilic desulfurizing bacterial consortium with sulfide removal potential for injection water of the oil reservoir

摘要:

【背景】海上油田见聚后产出水硫化物超标，影响到注聚水的配聚黏度，采用生物脱硫时，由于常规除硫菌难以适应除油后产出液的高温，使得脱硫效果不佳。【目的】分析海上采出液水处理过程的菌群结构，明确生物处理各节点的菌群构成变化；开展耐高温脱硫菌驯化筛选，获得耐高温的高效脱硫菌。【方法】采集来自胜利油田海三站的水样，以16S rRNA基因高通量测序技术分析样本菌群结构，并分别在不同温度(55、60和65 ℃)下的无机富集培养基中进行多轮转接驯化，结合常压室温等离子体(atmospheric and room temperature plasma, ARTP)诱变技术筛选获得耐高温的脱硫菌群，采用宏基因组测序技术分析富集菌群的组成，并测定其脱硫能力。【结果】处理前的采出液水样含有较多的嗜热菌和硫酸盐还原菌，如Thermodesulfovibrio、Pseudothermotoga、Thermolithobacter、Fervidobacterium、Thermovenabulales和Pseudomonas；以厌氧气浮除油工艺处理的出水中，嗜氢菌属(Hydrogenophilus)成为最主要的优势菌，该菌在中心三平台外输水中相对丰度占比为76%，在注聚平台水中相对丰度占比为84%。然而经过不断提高温度的驯化富集后，菌群中栖热菌属(Thermus)微生物占主要优势，相对丰度占比可达89.4%，此外也有少量嗜氢菌等；等离子体诱变后进一步提高了脱硫的效率，筛选获得的诱变后菌群在65 ℃可将培养液中8.88 mg/L的硫化物快速去除，去除率最高达100%，去除速率高达0.49 mg/(L·h)。【结论】通过对水样中菌群进行高温驯化和等离子体诱变，获得了耐65 ℃高温的高效脱硫菌群，提升了配聚水硫化物脱除效果，对高温油田的开发意义重大。

Abstract:

[Background] The sulfide in the produced water of offshore oilfield often exceeds the limit, which affects the viscosity of the polymer-containing injection water. The efficiency of biodesulfurization is poor due to the poor adaptability of conventional mesophilic sulfide-removing bacteria to the high temperature of the produced water after oil removal. [Objective] To analyze the changes of microbial consortium structure in the process of offshore produced water treatment and acclimate a thermophilic bacterial consortium for desulfurization. [Methods] Water samples were collected from Haisan Station of Shengli Oilfield, and 16S rRNA gene sequencing was performed to reveal the structure of the bacterial consortium. The acclimation was conducted in the inorganic medium at different temperatures (55, 60, and 65 °C) for multiple rounds, and atmospheric and room temperature plasma (ARTP) was employed to obtain the efficient thermophilic desulfurizing bacteria. Metagenome sequencing was employed to study the composition of the enriched bacterial consortium and then the desulfurizing ability of the consortium was determined. [Results] The produced water samples contained abundant thermophilic bacteria and sulfate-reducing bacteria, such as Thermodesulfovibrio, Pseudothermotoga, Thermolithobacter, Fervidobacterium, Thermovenabulales, and Pseudomonas. Hydrogenophilus became the most dominant bacteria in the effluent from the nitrogen gas-floated oil removal. The relative abundance of Hydrogenophilus in the effluent water of the central platform and the polymer injection platform was 76% and 84%, respectively. After the enrichment and acclimation with increasing temperature, Thermus became predominant, with the relative abundance of 89.4%, in addition to a few members of Hydrogenophilus. The efficiency of desulfurization was further improved by ARTP. The acclimated bacterial consortium could rapidly desulfurize the liquid containing 8.88 mg/L sulfide at 65 °C, with a removal rate of 100% and a removal speed up to 0.49 mg/(L·h). [Conclusion] An efficient desulfurizing bacterial consortium adapted to 65 ℃ was obtained, which improved the desulfurization of polymer-containing injection water. This study would be helpful for the development of high-temperature oil fields.