高温油藏内源微生物及其提高采收率潜力研究

大港孔店油田油藏特征、流体和微生物性质分析结果表明,属于高温生态环境,地层水矿化度较低,氮、磷浓度低,而且缺乏电子受体,主要的有机物来源是油气.油田采用经过除油处理的油藏产出水回注方式开发,油层中存在的微生物类型主要是厌氧嗜热菌,包括发酵菌(102个/mL～105个/mL),产甲烷菌(103个/mL);好氧菌主要存在于注水井周围.硫酸盐还原菌(SRB)还原速率0.002 μg S2-/(L·d)～18.9 μg S2-/(L·d),产甲烷菌产甲烷速率0.012 μgCH4/(L·d)～16.2 μgCH4/(L·d).好氧菌能够氧化油形成生物质,部分氧化产物为挥发性脂肪酸和表面活性荆.产甲烷菌在油氧化菌液体培养基中产生CH4,CO2为好氧微生物和厌氧微生物的共同代谢产物.这些产物具有提高原油流动性的作用.用示踪剂研究了注入水渗流方向.通过综合分析,油藏微生物具有较大的潜力,基于激活油层茵的提高采收率方法在该油田是可行的.

Potential Investigations of Indigenous Microbiological Properties and Its Enhanced Oil Recovery High-temperature Horizons

The analysis results of reservoir characteristics, properties of fluids and microbiological characteristics of the formation waters of the Kongdian oilfield of the Dagang oilfield demonstrated that this oilfield is a high temperature ecosystem with formation waters characterized by low mineralization. The concentrations of nitrogen and phosphorus compounds, as well as of electron acceptors, are low. Oil and oil gas are the main organic matter sources. The oilfield is exploited with produced water-flooding. The oil reservoir was inhabited mostly by anaerobic thermophilic microorganisms, including fermentative bacteria (102 cells/mL-105 cells/mL) and methanogenic (103 cells/mL) microorganisms. Aerobic bacteria were detected mainly in the near-bottom zone of injection wells. The rate of sulfate reduction aried from 0.002 to 18.9 mg S2-/(L·d), and the rate of methanogenesis from 0.012 mg CH4/(L·d) to 16.235 mg CH4/(L·d). Aerobic thermophilic bacteria were capable of oxidizing oil with formation of biomass, the products of partial oxidation of oil (volatile acids), and surfactants. During growth on the culture liquid of oil-oxidizing bacteria, methanogenic communities produced methane and carbon dioxide, which also had oil releasing capabilities. Using various labeled tracers, the primary filtration flows of injected solutions at the test site were studied. Our comprehensive investigations allowed us to conclude that the method for microbial enhancement of oil recovery based on the activation of the strata microflora can be applied in the Kongdian oilfield.