Study On One Set Of MEOR Technique

MEOR (Microbial Enhanced Oil Recovery) is a tertiary recovery method which aims to improve oil production by the means of microbial metabolisms. MEOR has many advantages such as cost-effective, environment-friendly and sustainable, which prompts scientists worldwide to put endless effort to develop it. Because of the complexity of its mechanisms, there is enormous room to research. With the increased demand for EOR in our country, study on the MEOR to obtain techniques monopolized by foreign firms and improving the output of crude oil, has strategic significance. In this paper, I selected several bacterias and yeasts by screening many times, then preliminarily optimized the culturing conditions and mediums for producing bio surfactants. After this, a large-scale fermentation to produce20m3broth has been achieved, then applied these20m3broth in oil field water-flooding to survy whether it could enhance oil recovery eventually or not.What jobs have I done in this paper are as below:Isolated several bacterias and yeasts from oil-water sample after enrichment, then classified these microbes by morphological observation and physiological characteristics of strains, used different screening media to find the outstanding strains which have many MEOR mechanisms such as reducing viscosity of crude oil or releasing gases. In this study, I used oil-excluding-ring test and capillary method (measurement of surface tension) to judge the yield of biosurfactants. The culturing conditions and mediums have been optimized by carrying on orthogonal experiments. Small pilot studies conducted in5L fermenter were finished before the10m3large-scale fermentation, which the kinetic regulation of many parameters(pH, biomass, yield of surfactant) provided a guidance for industrial fermentation. Finally, we produced20m3fermentation broth and applied it to oilfield trail.The results of this research are as follow:Three different EOR microorganisms screened are P1(Pseudomonas sp.),B1(Bacillaceae) and Yl (yeast).Both P1strain and B1strain can produce a significant amount surfactant; Yeast strainYl got the highest solid paraffin degradation rate of25.4%; The Shi’s fermentation tube test showed that P1strain can release large amount of gases in a short time by utilizing sucrose, which suggest P1can be used to improve the pressure of reservoir; After optimization, the mediums for surfactant producing has been simplified, so that the spending on nutrients was sharply reduced; In the oilfield trail, fermentation broth were injected and flooded through the formation, the microbial products worked in6wells of8and produced incremental303.46t crude oil.