Studies On Indigenous Microorganisms Flooding Experiment Of SaPu Oil Layer In Daqing Oilfield

In the paper, the most probable number method (MPN) was used to detect beneficial microbes, and analyze the community structure of indigenous fungus in 4 experimental Wells in Sabei of Daqing oilfield. Results showed that the selected region had rich microbial species and cardinally identical structure, but the beneficial microbe quantity in the produced liquid from production Wells was low than from injection Wells. The base of MEOR beneficial bacterium, methanogens, hydrocarbon oxiding bacteria and anaerobic fermentation bacteria etc, was big, the number of the harmful bacteria, the saprophytic bacteria and sulfate reducing bacteria was only in 10～10~2 every milliliter, and the content of iron bacteria was especially low. In the experimental reservoir the microbial structure possessed the basis with AMEOR (Activating Indigenous Microorganisms to Enhance Oil Recovery).According to the two main microbial flooding mechanisms, producing biological polymer and surfactant, a set of activators screening methods were established. With indigenous fungus activation systems applied by oilfield at present as reference, with bacteria, surface tension, viscosity, and pH value as physical and chemical indexes, determine the basic system for: carbon sources, nitrogen sources, inorganic salts and inhibitors. By evaluating the single factor indexes of the effect factors, single factor formula was got, and by orthogonal test method the optimal activators formula was determined. Activation agent with different concentrations cultivating indigenous fungus experiment showed, while the concentration in 1% ~ 7%, the crude viscosity reducing ratio had risen from 15% to 40%, and the oil-water interfacial tension changed little.From the microbial growth curve determination in the shaking bottles and cores, bacteria could grow in the core. Under the same culture conditions, in the core the logarithm growth occurred late and the number of steady growth bacteria was small than in the shaking bottles. The core displacement experiment results showed that it had appeared a approximate linear relationship between the recovery increment and the activation agent influx; Activators plug injection mode and continuous injection mode effected oil displacement little and improved recovery 4.26% and 4.73% respectively. The studies on indigenous fungus flooding system provided theory basis and technical support for AIMEOR field test.