METHOD OF WATER-PRODUCING WELL RECOVERY Russian patent published in 2015 - IPC E21B43/00 

FIELD: oil and gas industry.

SUBSTANCE: according to the method in a watered part of a formation at first remedial cementing is made to cut the inflow of stratal water off and to isolate the watered part of the formation by a cement plug setting. A geophysical survey is performed in the non-watered part of the formation. Intervals are identified with bigger permeability of the productive formation areas. An assembly with an end-to-end channel is run in at the drill string and set by means of an anchor packer device. It is oriented towards one of the permeable areas of the productive formation. Mill equipment with a downhole drilling motor, flexible shaft and cutter is run in to the well at a flexible tube. An opening is cut in the production string wall with the use of an oil-based solution. The mill equipment is run out from the well. A jet nozzle is run in to the well up to a discharge outlet of the guide assembly. Cement stone and rock is washed out behind the production string so that a radial borehole is formed. The radial borehole treatment is made through the jet nozzle by an acid composition so that a cavern is formed. The flexible pipe with the jet nozzle is lifted out of the well. The guide assembly is rotated, for example, per 180 degrees and similar operations are performed to tunnel the next radial borehole. The guide assembly is lifted to the height of the next interval in the permeable areas of the productive formation and the similar operations are performed to tunnel the next radial boreholes. Up to the upper radial boreholes of the well an oil string is run in and the above string is made of tubing strings with the area of a clearance hole equal to the sum of all the clearance holes in the radial boreholes. The well is brought to operation.

EFFECT: improved efficiency of the method due to the removal of conditions for swelling of clays contained in the productive formation at tunnelling the radial borehole in low-permeable terrigenous deposits of water-swelling clays.

3 ex, 6 dwg