石油集输系统中硫酸盐还原菌的分布和多样性

分别用亚甲蓝比色法、MPN法和16S rRNA基因序列分析方法,研究中国长庆油田(陕北)石油集输系统中原油和水样中H2 S的分布以及硫酸盐还原菌(SRB)的分布和多样性.结果表明,从油井井口经石油计量站再到石油综合处理站的集输系统中,原油中H2S的含量依次为105.80、99.70、24.57 mg.L-1;SRB的数量依次为98、300、680 CFU.100 mL-1.水样中H2S的含量依次为1.13、2.80、3.49 mg.L-1;SRB的数量依次为9 500、40 000、76 000 CFU.100 mL-1.集输系统中水样中SRB的数量平均为原油样品的100倍以上.原油井口中高浓度的H2S抑制了SRB的生长,SRB数量较少;随着H2S浓度的降低,抑制作用削弱并消失,使集输系统中SRB的数量逐渐增加.水样中H2S初始浓度较低,SRB数量较多,系统中H2S的含量随着SRB数量的增大而逐渐增多.由16S rRNA基因的序列分析表明,能够同时在水样和原油样本中检测到与脱硫弧菌属(Desulfovibrionaceae sp.)以及脱硫球菌属(Desulfococcus sp.)相关的SRB基因序列.但是,在水样中能够检测到与脱硫念球菌属(Desulfomonile sp.)、脱硫弯杆菌属(Desulfotomaculum sp.)和脱硫八叠球菌属(Desulfosarcina sp.)相关的SRB基因序列,而在原油样本中未检测到.在石油集输过程中由于环境条件的变化,水样和原油样品中SRB的多样性都有一定的增加.

Distribution and Diversity of Sulfate-Reducing Bacteria in a Crude Oil Gathering and Transferring System

The distribution of sulfureted hydrogen (H₂S) as well as sulfate-reducing bacteria (SRB) distribution and diversity in crude oil and oilfield production water samples from a oil gathering and transferring system in Changqing Oilfield of China were investigated by methylene blue colorimetric method, the most probable number technique and sequence analysis of the 16S rRNA gene, respectively. At the oil gathering and transferring system which from oil well through oil flowstation and then to oil comprehensive treatment station, the results showed that in oil samples, the content of H₂S were 105.80, 99.70, and 24.57 mg·L^-1, respectively; and the count of SRB were 98, 300, and 680 CFU·100 mL^-1, respectively. In water samples, the content of H₂S were 1.13, 2.80, and 3.49 mg·L^-1, respectively; and the count of SRB were 9500, 40000, and 76000 CFU·100 mL^-1, respectively. The abundance of SRB in the water samples is about 100 times than that in the crude-oil samples. High concentration of H₂S in oil well inhibited the growth of SRB, thereby the count of SRB in oil well were small. With the reduction of H₂S concentration, the actions of inhibition weakened and disappeared, then the number of SRB were gradual increase in the gathering and transferring system. For the initial concentration of H₂S in water samples was low, and the number of SRB were large, then the content of H₂S increased gradually with the number of SRB were increased. Sequence analysis of the 16S rRNA gene indicated that SRB related to Desulfovibrionaceae sp. and Desulfococcus sp. were detected in the water and crude oil samples, simultaneously. However, SRB related to Desulfomonilesp., Desulfotomaculumsp. and Desulfosarcina sp. were detected in the water samples but not in crude-oil samples. Abundance of SRB was increased due to the variation of environmental condition during the period of oil gathering and transferring process.