METHOD FOR DETERMINING THE PROPORTION OF MOBILE RESIDUAL OIL OF MATURE PRODUCTION FIELD Russian patent published in 2023 - IPC E21B47/00 G01V5/00 

FIELD: oil production.

SUBSTANCE: method for determining the proportion of movable remaining oil of mature production field. After determining the total remaining oil, non-radioactive water is additionally pumped into the pore space of the formation in the same volume as the indicator liquid. Non-radioactive water is pumped at a rate that is 10 times higher than the penetrant pumping rate until gamma radiation intensity readings stabilize. The wellbore is flushed in a volume equal to one and a half times the volume of the study interval. Determine the intensity of gamma radiation in the wellbore over the study interval. The proportion of dead remaining oil is determined, and the proportion of movable remaining oil is determined by the difference in values. The value of the share of movable remaining oil is determined using data on the intensity of gamma radiation of the reservoir, due to the penetration of radon into the reservoir, the intensity of gamma radiation associated with the presence of radon in the penetrant located in the wellbore above the study interval, the density of the reservoir rocks, the density of the penetrant, drilling fluid density, open porosity, thickness of the emitting layer of the radon solution, mass absorption coefficient of gamma radiation, distribution coefficient of radon concentration in oil and penetrant.

EFFECT: determining the proportion of movable remaining oil of mature production field in the mode of water displacement in an open hole or in a perforation interval and identifying intervals that are promising for further development.

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