中高温油藏内源微生物厌氧激活

Anaerobic activation of indigenous microorganism in the middle and high temperature reservoir

为了明确中高温油藏内源微生物厌氧激活产气的特点,在胜利油田选取了11个区块开展产气研究,温度范围分别为55~65℃、65~79℃、79~95℃。在模拟油藏条件下厌氧激活发现,低于79℃时,油藏内源微生物普遍能被激活并代谢产气;而高于79℃时,无明显甲烷气产生。利用不同碳源激活后发现,H_2/CO_2为碳源时,最大产甲烷速率可达1 500μmol/(g·d),显著高于乙酸钠和淀粉,这表明中高温油藏内产甲烷古菌以氢营养型为主。进一步对正理庄正南区块内源微生物群落组成研究,发现厌氧激活后古菌中Methanobacterium被激活成为优势菌群,有利于在油藏内代谢产甲烷气。厌氧激活前油水样中优势菌都是Pseudomonas,不同激活剂条件下优势菌群发生明显变化,H2/CO2和淀粉以激活Thermotoga为主,而乙酸钠则主要激活了油井中的Deferribacter。此外,该区块不同油井在相同激活条件下,其优势菌群趋向于一致,但油井和水井中优势菌群存在明显差异。通过对中高温油藏内源微生物厌氧激活的研究,为进一步提高微生物采油的效果奠定了基础。

In order to define the characteristics of gas production by indigenous microorganism under anaerobic activation, 11 blocks of middle and high temperature reservoir were selected to research in the Shengli Oilfield, which temperature ranges were 55 to 65 ℃, 65 to 79 ℃ and 79 to 95℃ .Indigenous microorganism could be activated to produce gas below 79 ℃ under simulated reservoir condition, whereas no significant methane gas was produced when temperature was above 79℃. The maximum methane production rate was up to 1 500 μmol/（g·d） when H2/CO2 was used as carbon source, significantly higher than those of sodium acetate and starch. Furthero, ore, Methanobacterium was activated to become the dominant microtlora under anaerobic condition in Zhengli Zhuang Zhengnan block, which favored to produce methane gas in the reservoir.Before anaerobic activation, the dominant bacteria were Pseudomonas in the samples and the dominant bacteria were changed under different activation conditions.He/CO2 and starch can activate Thermotoga, whereas sodium acetate mainly activated Deferribacter in oil wells. In addition ,the dominant flora of different oil wells tended to be identical in the block, but there were significant ditt〉rences in the dominant microtlora between oil well and water well. Our findings on the anaerobic activation of the internal mic＇ro（）rganism c（）uld serve ret^rence for further enhancing the effec＇t of microbial oil recovery.