NO3^-/NO2^-对渤海湾油藏中硫酸盐还原菌SO4^2-还原活性的抑制效应

NO_3^-/NO_2^- inhibits sulfate-reducing activity of the enrichment culture of sulfate-reducing prokaryotes from an off-shore oil reservoir at Bohai Bay,China

长期注水开发促进了渤海湾海域油藏中硫酸盐还原菌(SRP)的生长繁殖,产生了大量H2S,引起油藏酸化(souring)等问题.本文首先以改进的API RP 38培养基富集了渤海湾海域某油藏采出井井口采出液中的SRP,再通过批次试验研究了不同浓度NO3-和NO2-对SRP富集培养物SO42-还原活性的抑制效应.结果表明:渤海湾海域油藏中的SRP富集培养物SO42-还原活性较强,SO42-还原速率为10.4 mmol SO42-·d-1·g-1dry cell;加入浓度为0.4、0.8、1.8、4.2 mmol·L-1NO3-时,SRP富集培养物的SO42-还原活性均可被抑制,维持时间分别为5、9、20和大于35 d;加入浓度为0.6、0.9、1.4、2.6或4.6 mmol·L-1的NO2-时,SO42-还原活性也被抑制,维持时间分别为3、12、22和大于39 d.SRP富集培养物具有异化NO3-还原成NH4+的代谢途径.当环境中同时存在SO42-、NO3-、NO2-时,SRP富集培养物优先利用NO3-和NO2-.SRP富集培养物对电子受体的优先利用及NO2-的毒性效应是NO3-/NO2-抑制渤海湾海域油藏中SO42-还原活性的主要原因.

Long-term injection of sulfate-rich water into oil reservoirs stimulates the proliferation of sulfate-reducing prokaryotes （SRP） therein and results in production of a great amount of H2 S, leading to souring in oil reservoirs and related environmental problems. In this study, we first, using modified API RP 38 medium, enriched SRP present in production water from a producing well at Bohai Bay, China, and then examined the inhibitory effects of nitrate or nitrite on sulfate reduc- tion activity of the SRP. Results showed that the enriched SRP culture exhibited a high sulfate re- duction activity as indicated by a sulfate-reducing rate of 10.4 mmol SO42-· d-l·g-1 dry cell. In presence of 0.4, 0.8, 1.8, and 4.2 mmol ·L-1 nitrate, sulfate reduction was inhibited for 5, 9, 20, and over 35 days, respectively. With the addition of 0.6, 0.9, 1.4, 2.6 and 4.6 mmol·L-1 of nitrite, the inhibitory period lasted 3, 12, 22, and over 39 days, respectively. The SRP enrich- ment culture could dissimilatorily reduce nitrate to ammonium. When sulfate, nitrate and nitrite co-existed, nitrate or nitrite was preferentially used over sulfate as electron acceptor by the enriched SRP. This competitive use of electron acceptor and the strong inhibitory effect of nitrite possibly ac- counted for the suppression of nitrate and nitrite on the sulfate-reducing activity of the enriched SRP cultures from offshore oil reservoir at Bohai Bay.