METHOD OF OIL FORMATION TREATMENT Russian patent published in 2014 - IPC E21B43/27 E21B43/22 

FIELD: oil and gas industry.

SUBSTANCE: method of oil formation treatment includes running of a string with a packer to the well, setting of the packer above the oil formation and subsequent injecting and flushing through the string to the oil formation of hydrocarbon solvent and acid agent in volumes exceeding filtration resistance in the formation zone remote from the well over the same value in the bottomhole zone, process withheld and removal of waste reaction products from the treated area by depression impact on the well. Then the pipe string at the well mouth below the packer is equipped with impulse liquid pulsator. At that a valve is mounted between the packer and liquid pulsator. An ejector pump with a feedthrough accessory is mounted above the packer. The string is run in to the well so that the packer is placed above the formation. Hydrocarbon solvent is injected to the string in pulsed mode, the packer is set, and hydrocarbon solvent is flushed to the formation by process fluid under pressure not exceeding the permitted pressure to the formation. The packer is released and the well remains under exposure. Then the well is washed out and acid solution is injected to the well, the packer is set, acid solution is flushed to the formation by process fluid under pressure not exceeding the permitted pressure to the formation. The packer is released and the well remains under exposure. After exposure period the valve is actuated and impulse liquid pulsator is cut off. The packer is released, the string is run in additionally so that radial openings of the valve are opposite the formation; the feedthrough accessory is removed from the ejector pump and a blind plus is installed instead. Then the packer is set, and reaction products are extracted by process fluid injecting along the string through the ejector pump and the well is completed through its tubing-casing annulus above the packer.

EFFECT: increased efficiency of the bottomhole zone treatment, excluded damage of the well casing string.

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