生物竞争抑制作用对渤海J油田微生物降解驱油聚合物功能的影响

Impact of bio-competitive exclusion on the degradation of polymers for oil displacement by endogenous microorganisms in Bohai J-oilfield

摘要:

【目的】揭示可降解驱油用聚合物的油藏内源微生物群落组成，分析生物竞争抑制作用(bio-competitive exclusion，BCX)对微生物聚合物降解功能的影响。【方法】通过室内培养实验，观察BCX对驱油用聚合物黏度的影响，随后借助高通量测序技术分析渤海J油田中与聚合物降解相关的微生物菌种，并探寻样本中丰度较高的聚合物降解功能基因─酰胺酶、加氧酶、硫化氢生成酶基因。之后，比对测序结果，采用实时荧光定量法验证上述功能基因在样本之间的含量差异，最后进一步注释携带上述功能基因的微生物群落组成。【结果】BCX可有效地延缓驱油聚合物黏度的损失。油田中与聚合物降解相关的微生物有Acetomicrobium、Tepidiphilus、Thermoanaerobacter、Fervidobacterium、Ralstonia、Halomonas、Roseovarius、Deferribacteraceae和Comamonadaceae等9类菌种。高通量测序分析得到样本中BCX可显著下调丰度的聚合物降解功能基因共计有7种，其中酰胺酶基因ansB、加氧酶基因ssuD在样本之间的含量经定量验证，发现受到了BCX的抑制，这与测序结果相一致。群落组成注释表明，BCX对渤海J油田聚合物高效降解菌─代尔夫特菌(Delftia)存在明显的抑制作用。【结论】揭示了油田中可降解驱油用聚合物的内源微生物群落组成，发现BCX对微生物降解聚合物的抑制效用，证实BCX有助于解决海上油田聚合物驱稳粘问题。

Abstract:

[Objective] This study aimed to reveal the composition of endogenous microbial community degrading the polymers for oil displacement in the reservoir and analyze the influence of bio-competitive exclusion on the microbial degradation of polymers. [Methods] Through indoor culture experiments, we observed the influence of bio-competitive exclusion on the viscosity of the polymers, and used high-throughput sequencing technology to analyze the microbial strains related to polymer degradation in Bohai J-oilfield. We then mined the genes (encoding amidase, oxygenase, hydrogen sulfide-generating enzyme) with high abundance and involved in polymer degradation in the samples. After that, we employed the real-time fluorescence PCR to compare the abundance of the above-mentioned functional genes between samples, and finally annotated the microbial taxa carrying the above-mentioned functional genes. [Results] Bio-competitive exclusion mitigated the viscosity loss of the polymers for oil displacement. Nine taxa of microorganisms related to the degradation of polymers were identified, including Acetomicrobium, Tepidiphilus, Thermoanaerobacter, Fervidobacterium, Ralstonia, Halomonas, Roseovarius,Deferribacteraceae, and Comamonadaceae. High-throughput sequencing revealed that bio-competitive exclusion significantly down-regulated the abundance of 7 genes involved in the polymer degradation in the samples. The measurement of abundance in samples showed that the abundance of the amidase gene ansB and the oxygenase gene ssuD was down-regulated by bio-competitive exclusion, which was consistent with the sequencing results. The community composition annotation indicated that bio-competitive exclusion significantly inhibited Delftia, a highly efficient bacterial taxa for polymer degradation in Bohai J-oilfield. [Conclusion] We revealed the endogenous microbial taxa related to the degradation of polymers for oil displacement in the oilfield and discovered the inhibitory effect of bio-competitive exclusion on the degradation, confirming that bio-competitive exclusion can help to stabilize the viscosity of polymers for oil displacement in offshore oilfield.