METHOD OF FORCING OUT RESIDUAL OIL FROM OIL FORMATION Russian patent published in 1998 - IPC

FIELD: oil and gas production. SUBSTANCE: invention, in particular, relates to microbiological methods of developing watered oil formations. Method includes activation of microflora by pumping in crude oil and aerated aqueous solution of nutrients into aerobic zone of injection well. Crude oil drawn out from production well is pumped in amount corresponding to 20-30% of pore volume of the production well aerobic zone. When concentration of hydrocarbon-oxidizing bacteria in this zone is less than 1000 clones per 1 ml or in complete absence of these bacteria, into aerobic zone, a culture of hydrocarbon-oxidizing bacteria is added. If crude oil contains less than 25% of 10³-n-paraffins, they are supplemented by light hydrocarbon fractions (e. g. distillate). EFFECT: enhanced efficiency of microbiological method. 3 cl