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含硫注采系统生物群落结构与硫化物含量影响因素分析

Analysis of biological community structure and factors influencing sulfide content in sulfur-bearing injection-production systems

  • 摘要:
    目的 为高效开展H2S防治,对靖边采油厂杨米涧区块“注水−采油”系统微生物群落进行结构分析与功能预测,并对硫化物生成关键因素开展分析研究。
    方法 利用NovaSeq6000高通量测序方法对比了采出水、集输、水处理、注水4个阶段的水样生物群落差异性,利用FaPROTAX菌群功能分析方法对上述水样进行功能预测分析。
    结果 ①含硫油井中的脱硫菌门占比为16.7%~43.0%,显著高于集输、水处理和注水阶段,说明地层温度适宜的厌氧环境适于硫酸盐还原菌(SRB)生长繁殖,是产生H2S的主要原因;②含硫井O.3.1水样SRB和硝酸盐还原菌(NRB)在菌群中占比分别为33.02%和21.2%,但硝酸盐还原作用占比达到硫酸盐还原作用的2.3倍以上,说明NRB的存在对SRB具有明显的抑制作用。
    结论 持续配注硝酸盐质量浓度高于40 mg/L以上的注水,可显著抑制SRB生长,减少H2S的产生,保障现场安全生产。

     

    Abstract:
    Objectives To prevent and control H2S efficiently, this study conducted structural analysis and functional prediction of the microbial community in the "water injection-oil extraction" system which is located in the Yangmijian block of Jingbian Oil Production Plant, and analyzed the key factors of sulfide generation.
    Methods The NovaSeq6000 high-throughput sequencing method was used to compare the differences in the microbial community structure of water samples from four stages: produced water, gathering and transportation, water treatment, and water injection. The FaPROTAX bacterial functional analysis method was used to predict the functions of these water samples.
    Results Firstly, the proportion of desulfurizing bacteria in sulfur-containing oil wells ranged from 16.7% to 43.0%, significantly higher than that in other stages, indicating that the anaerobic environment with suitable formation temperature is conducive to the growth and reproduction of sulfate-reducing bacteria (SRB), which is the main reason of hydrogen sulfide production. Secondly, in the water sample O.3.1 of the sulfur-containing well, the proportions of SRB and NRB in the bacterial community were 33.02% and 21.20%, respectively. However, the proportion of nitrate reduction function was more than 2.3 times higher than that of sulfate reduction, indicating that the presence of nitrate-reducing bacteria has a significant inhibitory effect on sulfate-reducing bacteria.
    Conclusions Lasting injection of water with nitrate mass concentration higher than 40 mg/L could significantly inhibit the growth of sulfate-reducing bacteria and reduce the production of hydrogen sulfide, thus ensuring the safety of on-site production.

     

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