COUPLING FOR HYDRAULIC FACING IN A WELL Russian patent published in 2022 - IPC E21B34/06 E21B43/26 

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry, and in particular to devices designed for hydraulic fracturing, included in the assembly of casing strings. A coupling for hydraulic fracturing in a well contains a housing 1 in the form of a stepped pipe, in the upper stage 2 of which a bore 3 with a diameter D1 is made, and in the lower stage 4 - a bore 5 with a diameter D and circulation holes 6, evenly spaced around the circumference, D>D1. In bores 3 and 5, a stepped differential bushing 7 is installed with the ability to move, the lower step 8 of which in the initial position overlaps the circulation holes 6, and the upper step 9 is connected to a scraper 10 with a sharp edge 11. In the conjugation of the inner cylindrical surfaces of the bores 3 and 5 of the housing 1 and the outer cylindrical surfaces of the steps 8 and 9 of the differential sleeve 7, a gap is made. In the annular groove 12 on the outer surface of the lower step 8 of the differential sleeve 7, a lock 13 is installed in the form of a split elastic ring. A closed cavity 14, filled with air at atmospheric pressure, is located between the housing 1 and the differential sleeve 7 for its axial movement. In the closed cavity 14, an annular bore 15 is made to interact with the lock 13 after axial movement of the differential sleeve 7 upward to open the circulation holes 6. In the initial position, the circulation holes 6 are filled with heat-resistant grease 16 and are closed from contact with the wellbore with a ring 17 made of non-woven synthetic material and glued into the annular groove 18 on the outer surface of the housing 1. In the bore 5 of the lower stage 4 of the housing 1 under the differential bushing 7, a shutter 20 of circulation holes 6 in the form of a cylindrical bushing is installed with the ability to move. On the outer surface of the overlap 20 in the annular groove 21, a stopper 22 is installed in the form of a split elastically deformable ring. To fix the shutter 20 in the closed position of the circulation holes 6, an annular bore 24 is made in the bore of the housing 1, interacting with the stopper 22 after it has been moved to the upper position. Inside the cover 20, there are steps 25 and 26 for its movement in order to close or open the circulation holes 6.

EFFECT: increasing reliability and efficiency of the device.

1 cl, 3 dwg