METHOD FOR PRESERVING COLLECTING PROPERTIES OF FACE-ADJACENT AREA OF PRODUCTIVE BED OF OIL-EXTRACTIVE WELL Russian patent published in 2005 - IPC

FIELD: oil and gas extractive industry.

SUBSTANCE: method includes placing water solution of carnallite ore, either modified, concentrated, or mixtures thereof, said solution is used at maximal for well temperature conditions concentration and is pumped in amount, necessary and enough for forming a hydraulic column in well shaft above ceiling of productive bed and along remaining shaft height well is filled with water up to mouth. Carnallite ore used has composition, in percents of mass: potassium chloride 20.5-21.5; sodium chloride 19.5-22.5; magnesium chloride 24.0-27.0; crystallization water 29.5-30.5. Modified ore has composition, in percents of mass: potassium chloride 23.0-29.5; magnesium chloride 31.8-46.0; crystallization water - the rest. Said water solution is prepared by dissolving ore in fresh technical water, drained from oil preparation plants, or in bed water. In case of dissolving in bed water, the latter is pumped from well at temperature 60-90°C. During perforation of well, value of technological liquid hydraulic column above productive bed ceiling is taken equal to (1.03-1.07)-(1.05-1.1)P_b, where P_b - productive bed pressure. Water solution of carnallite ore is used at density 1.23-1.37 t/m³. During use of said solution as working body of force wells it is used at density 1.05-1.20 t/m³, and solution also contains swelling inhibitor for argillaceous component of oil and gas bearing bed, like oxyethylenedendiphosphone acid, in amount 0.05-0.15% of used dissolved ore mass.

EFFECT: higher efficiency.

1 cl, 4 ex