Study On Indoor Performance And Field Flooding Effect Evaluation Of Microorganism In Zhan 3 Block Of Shengli Oilfield

At present,the high-water and low-oil-producing conditions exist in the development of microbial flooding in Shengli Oilfield,a high efficiency microbial S2was cultivated by comparing with the existing microbial S1 and analyzing the properties of formation water and crude oil.At the same time the viscosity reduction rate of crude oil,four components,the wettability,emulsifiable dispersion and interfacial properties of rock were evaluated.The best permeability range of the microbial S2 system was determined by the indoor physical simulation experiment.In the current field of microbial flooding ineffective case,the effect of the microbial flooding stage and water flooding stage are analyzed,the distribution of the dominant channel and the relevant parameters are identified and calculated.It provides valuable advice for the implementation of the follow-up microbial flooding technology.The results show that the total salinity of the formation water is less than 1×10⁴mg/L in Zhan 3 of Shengli Oilfield,the content of heavy metal elements in the formation water is low and the pH is between 7.2 and 7.8.The crude oil is heavy oil,colloid and asphaltene are total 30%.After the action of microorganism S2 and crude oil,the viscosity of crude oil can be from 1197 mPa·s decreases to 432.7 mPa·s?60°C?,and the interfacial tension of oil and water decreases from 40.94 mN/m to13.0 mN/m,and the contact angle decreases from 82°to 21.07°,and the crude oil has a strong ability of emulsifying and dispersing,the performance is better than the microbial S1.The results show that with the microbial S2,the optimum permeability range is 800¹300×10^-3?m²,the microbial S2 can reduce the water content and increase oil production and the effect is best at 1000×10^-3?m².The effect of microbial flooding is evaluated by the water storage index,water consumption index and water absorption index,water level and oil level of single well.Fuzzy comprehensive evaluation and permeability distribution model were used to identify and calculate the distribution of dominant channels and the calculate of parameters.The results show that 12%of the wells and 56%of the channeling wells are present.The average permeability is as high as 2798×10^-3?m² and the average pore radius is as high as 510?m.