油田硫酸盐还原菌酸化腐蚀机制及防治研究进展

硫酸盐还原菌(Sulfate reducing bacteria,SRB)是一些厌氧产硫化氢的细菌的统称,是以有机物为养料的厌氧菌。它们广泛分布于pH值6-9的土壤、海水、河水、淤泥、地下管道、油气井、港湾及锈层中,它们生存于好气性硫细菌产生的沉积物下,其最适宜的生长温度是20-30℃,可以在高达50-60℃的温度下生存,与腐蚀相关的最主要的是脱硫脱硫弧菌(Desulfovibrio desulfuricans)。 它们是许多腐蚀问题的主因,例如油田系统金属管路的腐蚀等。在海上油田生产中,海水常被注入油井用于进行2次采油。富含硫酸盐的海水能加速油藏中SRB的生长,随之H₂S大量产生,引起油田水的酸化,H₂S具有毒性和腐蚀性,增加石油和天然气中的硫含量,并可能引起油田堵塞。SRB引起的腐蚀问题是拭待解决的最主要问题。国内外治理该问题的途径主要有物理杀灭、添加化学杀菌剂等方法,但是这些方法成本高,持续效果不显著。近几年来国外学者开始重点关注利用生物竞争排斥技术(Bio-competitive inhibition technology,BCX)控制硫酸盐还原菌的生长代谢的方法,该方法的原理为通过加入特定的药剂,激活油藏中的本源微生物或加入外源微生物,使其与SRB竞争营养源或产生代谢物抑制SRB的生长代谢,进而抑制H₂S的产生。GMT-LATA的科学家对在厌氧油气储层和开采系统中硝酸盐还原菌的作用进行了最早的研究,认为该细菌可以抑制硫酸盐还原菌的代谢活动。随后BCX技术已经在国外部分油田得到了应用,国内还没有在海油生产中应用的报道,但是也有学者对该方法进行了研究。

Acid corrosion mechanism of the sulfate-reducing bacteria and protecting studies in oilfield

Sulfate-reducing bacteria(SRB) are prokaryotic microorganisms that obtain energy by oxidizing organic compounds or molecular hydrogen H₂ while reducing sulfates to hydrogen sulfide. SRB occur widely in anaerobic environments (e.g. soils, freshwater, marine sediments, underground pipelines, oil and gas wells, and rust layers and harbours) where the pH values range from 6 to. Desulfovibrio desulfuricans is known as one of the most important members of SRB that are involved in corrosions of metal facilities including alloy oil systems. In practice, sulfate- rich seawater, which is often injected into oil wells for secondary or oil recovery, will favor the growth of SRB, leading to more H₂S production, water acidification in oilfields. As a consequence, quality of oil and natural gas may become worsened, and oil blockage may take place. By and large, SRB-caused corrosion represents one of the most serious problems waiting being resolved. So far, More measures has been taken to slow down SRB-caused corrosion, while sustainable approaches with lower cost have to be developed. Among these, Bio-Competitive Inhibition Technology (BCX) is of great potential to controlling growth and metabolism of SRB. The principle of this technology is that specific agents, original or activated microbes are added to the systems, and these players then compete with the SRB for source of nutrition, and produce metabolites to inhibit the growth of SRB. In this article, we review many aspects mentioned above, and highlight the future directions in this research field.