Microbial enhanced oil recovery technology refers to the use of specific functional bacteria in the reservoir, with crude oil as the carbon source for metabolic growth, in the process of producing proliferation of bacteria, while producing biosurfactants, organic acids, gases, enzymes and other active substances, acting on the reservoir, improving the flow capacity of crude oil, adjusting the wettability of the reservoir, degrading colloidal asphaltenes, etc., acting on the residual oil of the reservoir.It can make the reservoir tend to the growth and proliferation of crude oil, greatly delay the action period, change the wettability of rock and reduce the interfacial tension.
Underground crude oil viscosity < 10000mPa.s, formation temperature < 120°C, oil saturation >10%, reservoir permeability >10mD, lithology is not limited, formation water salinity < 20×104mg / L; 1.Corresponding to the injection-production relationship, the oil and water wells have good connectivity, and there are more than 2 connected injection wells; It has high remaining oil saturation, ≥25%; The wax deposition in the oil well is clear, and the impact on production is clear; The well is in good condition, the oil well can be produced normally, there is no low pressure leakage layer and no fault ; the pumping related equipment is complete and intact, and the wellhead device can operate normally; The dynamic and static data are complete, which is convenient for subsequent application effect analysis.
The bacterial library is rich: the action system can be quickly established to match different reservoir requirements; Strong environmental adaptability: wide resistance to temperature and salt; High efficiency and long validity: direct effect on crude oil, rapid degradation; it tends to proliferate, and the effect lasts for a long time; Low environmental cost: biological metabolic end products are carbon dioxide and water, no secondary damage; Temperature resistance: 180°C below the reservoir is generally applicable.
1.Xinjiang four note 11 wells: block in 2014.01-2015.7 measures during the period, the effect of increasing oil and reducing water is remarkable, absolute increase oil 9030t; considering the natural decline to increase oil 12320t, 4 injection 11 mining, combined with profile control and flooding, the precipitation reached 26.2%;
2.Liaohe No.4 injection 10 production well : the injection and production are reduced to about 0.5, and the liquid production between the measures is stable at 65000-70000 m3. The effect of plugging and viscosity reduction in the microbial block is more prominent；The peak daily oil increased by more than 7t, and the average daily oil after the measures in 2020 was more than 1.6t higher than the peak daily oil before the measures；Before the contrast measures, the daily average water cut decreased by 1.9%, up to more than 10%；Compared with the same period before and after the measures, the annual cumulative oil production of microbial displacement is about 19.4% higher than that of pure water flooding；More than 2,000 tons of oil will be added in the same period of 2021；Compared with pure water flooding, microbial flooding increased oil production by 24.8% ( without considering annual decline of 5 ~ 7% ).
