为了探讨青海花土沟高矿化度油藏利用内源微生物生长代谢提高原油采收率的可行性，用最大可能数法（MPN法）对油藏内源微生物群落组成进行分析，筛选激活体系，考查乳化、产酸性能，同时对微生物作用前后的原油进行气相色谱分析，通过16S rDNA序列分析，进一步了解油藏内源微生物群落。结果表明，腐生菌、烃氧化菌、发酵菌、硝酸盐还原菌是该油藏的主要微生物群落；激活体系能有效地激活内源微生物乳化液蜡，并产酸，内源菌浓度达107/mL，发酵液表面张力由57.44mN/m降至38.5mN/m，pH值由7.19降至6.56；选择细菌通用引物对菌株16S rDNA序列进行基因扩增、测序，测序结果用Blast进行同源性比较得分离菌株分别为Bacillus sp.和Halomonas sp.，激活后的内源菌选择性降解饱和烷烃（C11~C20，C28，C33）。在花土沟高矿化度油藏实施内源微生物采油具有可行性。
In order to study the feasibility of enhancing oil recovery rate in Qinghai oil field with hypersalinity, the composition of indigenous microorganism community was analyzed by MPN counts, the nutrient packages for emulsification were evaluated, the acid production was studied and the sequence of 16S rDNA and the saturated hydrocarbon of oil samples were analyzed. Results show that the main microbial populations in the reservoir are saprophytic bacteria, hydrocarbon-oxidizing bacteria, fermentative bacteria and nitrate reducing bacteria. The indigenous microorganisms can use nutrition added for emulsification through acid production; its cell concentration can reach 107cells/mL, and the surface tension is reduced from 57.44mN/m to 38.5mN/m. The pH value of the fermentation liquor with nitrogen source is decreased from 7.19 to 6.56, and the pH value of the fermentation liquor added with carbon and phosphorous source remains unchanged, so the optimal nutrient was the nitrogen source (0.1% yeast and 0.1% peptone), which was used for all subsequent experiments. The total DNA was extracted, 16S rDNA universal primers were applied for gene amplification, and the results were sequenced and analyzed. The species isolated were confirmed to be Bacillus sp. and Halomonas sp.; the saturated hydrocarbon was catalyzed selectively (C11~C20, C28, C33), which exhibited a great potential to enhance oil recovery rate.
