海洋环境中油气管道的微生物腐蚀研究进展

海上油气集输管道的腐蚀能够导致严重的环境风险和经济损失,其中微生物腐蚀一直以来被认为是造成该问题的主要因素之一。针对海洋环境油气管网中腐蚀性微生物的来源进行了分类,包括油藏内源性微生物、外注海水以及微生物采油（MEOR）引入的外源性微生物。分析了海底油藏储层中流体化学物质特性,确认其富含甲烷、硫化物、挥发性脂肪酸等,并依据内源微生物代谢及产物特征进行了分类,包括硫酸盐还原菌（SRB）、产甲烷菌、发酵菌以及铁还原菌（IRB）。同时,通过举例分析某油田采出水中微生物群落丰度特征,阐明了外源微生物长期受到油田开采环境胁迫后微生物群落的变化规律。在此基础上,进一步针对海上油气集输管网内涉及的微生物代谢产物理论、电活性微生物腐蚀理论以及腐蚀性微生物之间的协同与拮抗作用进行了全面的归纳总结。最后,对目前以纯培养或模式菌株混合培养为主要方式的微生物腐蚀研究中存在的问题进行了讨论,并对基于生物技术的新型防腐手段进行了展望。

Research Progress on Microbiologically Influenced Corrosion of Oil and Gas Pipelines in Marine Environment

Corrosion of offshore oil-gas gathering and transportation pipelines can lead to serious environmental risks and economic losses. With the continuous development of China''s marine energy industry, it is imperative to accelerate the rational exploitation and utilization of offshore oil-gas resources as well as upgrade the oil-gas production equipment. As an important part of oil-gas gathering and transportation networks, submarine pipeline is known as the "artery" of offshore oil-gas production systems. Under actual working conditions, submarine pipelines are inevitably exposed to corrosion and failure. Microbiologically influenced corrosion (MIC) has been considered one of the main factors causing this problem. According to statistics, more than 20% of the oil-gas pipeline corrosion and oil leakage accidents are directly or indirectly related to MIC. The vast ocean includes a wide range of extreme environments such as high salt, high pressure, and low temperature environments. Marine environments are more diverse and complex than terrestrial environments, indicating that marine microbes are more tolerant to extreme conditions. Herein, the sources of corrosive microorganisms in offshore oil-gas pipelines, including reservoir endogenous microorganisms, exogenous microorganisms introduced by seawater injection, and microbial enhanced oil recovery, were classified. The characteristics of fluid chemical substances in submarine reservoirs were analyzed. It was confirmed that they were rich in methane, sulfides, and volatile fatty acids, and they were classified according to the characteristics of endogenous microbial metabolism and products, including sulfate-reducing bacteria, methanogens, fermentative bacteria, and iron-reducing bacteria. Moreover, the characteristics of microbial community abundance in the produced water of an oilfield were analyzed with an example, and the evolution rule of the microbial community under long-term oilfield environmental stress was clarified. Complex gathering and transport networks are particularly prone to biofilm formation and metabolite accumulation, which may cause or exacerbate corrosion problems. A corrosive biofilm, composed of various environmental microorganisms, is a general life form used by microorganisms to resist changes in the external environment and maintain homeostasis of the internal environment, which includes a complex symbiotic relationship between microorganisms with different metabolic characteristics. Accordingly, theories of metabolite-MIC, extracellular electron transfer-MIC, and synergism/antagonism among corrosive microorganisms in offshore pipeline networks were further reviewed. Pure/mixed culture in laboratory conditions can hardly represent the complexity of in situ biofilms in oil-gas pipelines; therefore, it is almost impossible to reconstruct the corrosion behavior of microorganisms in a real service environment. Industrial bactericides are one of the most widely used strategies for MIC in oil-gas pipeline networks. Advanced composite bactericides often possess broad-spectrum antibacterial properties, low toxicity, and sustained bactericidal activity. However, bactericides have drawbacks such as increased microbial resistance, difficulty in degradation, and deterioration of crude oil quality. Therefore, it is extremely challenging to detect the corrosive microbial community and the metabolic processes leading to corrosion accurately under actual working conditions. Advanced biological detection technologies, including environmental genomics, microfluidics, and high-throughput rapid detection technology, should be fully utilized in future research on the MIC of oil-gas pipelines. In this paper, the types of potential microbial species, types of MIC, and the corrosion mechanisms are summarized in detail, and novel anti-corrosion methods based on biotechnology are proposed.