Abstract

Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon. For the first time, sulfidogenic communities in injection waters of two Algerian oilfields, Tin Fuin Tabankort (IT3) and Stah (IS2) were examined using the 16S rRNA gene cloning and sequencing approach. Water samples were inoculated into selective medium for sulfate-reducing bacteria and incubated under anaerobic conditions at 45 °C. The total number of culturable sulfidogenic microorganisms in the samples obtained from the two sampled waters (IT3 and IS2) was 2.4 × 10⁵ cells/mL and 3.9 × 10⁴ cells/mL, respectively. Scanning electron microscopy analyses showed different morphological forms reflecting the diversity of sulfidogenic communities. 16S rRNA gene sequencing and phylogenetic diversity analyses revealed that both water reservoirs harbor large amounts of anaerobic bacteria. However, a majority of all the sequences analyzed (e.g., 34% in the IS2 and 84% in the IT3 samples) were not assigned to any known bacterial group, suggesting that subsurface waters harbor very large sulfidogenic anaerobic microbial communities of as yet undescribed bacterial phyla. Proteobacteria were found to be the most dominant phylum in the IS2 sample (49%); however, no Proteobacteria were detected at the IT3 production well. The Firmicutes phylum (10%) was detected in the two water samples, whereas Bacteroidetes phylum (7%) was retrieved only in IT3. The most abundant related genera were: Desulfotomaculum, Porphyrobacter, Hyphomicrobium, Acidocella, Comamonas, Ramlibacter, Pseudomonas, Enterobacter and Flavitalea. No shared operational taxonomic units were observed among the two samples analyzed, demonstrating the uniqueness of each subsurface water well. This study demonstrates the diversity of the sulfidogenic bacteria that might play a critical role in the souring mediated corrosion of metallic oilfield pipelines. This information could help oilfield companies develop better anticorrosion treatments and strategies.

摘要

微生物对金属油田管道的腐蚀是一种代价高昂但知之甚少的现象。首次使用 16S rRNA 基因克隆和测序方法检查了阿尔及利亚两个油田 Tin Fuin Tabankort (IT3) 和 Stah (IS2) 注入水中的硫化物群落。将水样接种于硫酸盐还原菌选择性培养基中，在45℃厌氧条件下培养。从两个采样水（IT3和IS2）获得的样品中可培养的硫化微生物总数分别为2.4×10 ^{5 个}细胞/mL和3.9×10 ⁴细胞/毫升，分别。扫描电子显微镜分析显示不同的形态形式反映了硫化群落的多样性。16S rRNA 基因测序和系统发育多样性分析表明，两个水库都含有大量厌氧菌。然而，分析的所有序列中的大多数（例如，IS2 中的 34% 和 IT3 样品中的 84%）未分配给任何已知的细菌群，这表明地下水域拥有非常大的硫化厌氧微生物群落，这些微生物群落尚未描述的细菌门。发现变形菌是 IS2 样本中最主要的门 (49%)；然而，在 IT3 生产井中没有检测到变形菌。该厚壁菌门在两个水样中检测到拟杆菌门 (10%) ，而仅在 IT3 中检测到拟杆菌门 (7%)。最丰富的相关的属有：脱硫肠，Porphyrobacter，生丝微菌属，Acidocella，丛毛单，Ramlibacter，假单胞菌属，肠杆菌和Flavitalea。在分析的两个样本中没有观察到共享的操作分类单元，这证明了每个地下水井的独特性。这项研究证明了硫化菌的多样性，它们可能在金属油田管道的酸化介导腐蚀中起关键作用。这些信息可以帮助油田公司开发更好的防腐处理方法和策略。