Abstract: Microbial enhanced oil recovery (MEOR) is a new technique combining with biology and oilfield development technology, by which EOR of low permeability reservoirs could increase through improving the in-layer and interlayer contradictions. MEOR, as one of important stimulation measures at late stage of oilfield development, is characterized by low cost, simple operation and according with the demand of environment protection, etc. The effects of MEOR include as follows: being favorable to oil-gas percolation, changing wettability of rocks, improving hydrocarbon migration, reducing surface tension of emulsified oil, decreasing crude viscosity and improving sweep efficiency, etc. Meanwhile, its negative influences under the reservoir conditions should be recognized such as influence of microorganism on reservoir permeability, influence of the products of microorganism on formation plug, influence of iron sulfides precipitation and biochemical affection of microorganism.

Key words: MEOR, percolation, seepage, research, study