DEVICE FOR UPPER AND LOWER ENDS OF EXPANDABLE TUBES, WHICH PREVENTS END NARROWING AT THEIR EXPANSION Russian patent published in 2014 - IPC E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: device includes bushings rigidly fixed to the upper and lower pipe ends, to end inner chamfers and though cuts placed evenly along the perimeter from butt ends, which can form the upper and lower bell mouths folded outside after expansion. The bushings have outer diameter, which is equal to inner diameter of the well after expansion. The end section is thickened and it may be connected rigidly to the well walls after expansion. The inner chamfer has length equal to the length of thickening; it consists of two chamfers, at that the upper most one is made under an angle four times bigger than the angle of slope of the expanding tool while the inner chamfer is made with the angle twice bigger. 7 or 8 cuts are made with length equal to the length of thickening and width equal to two thickness value of the bushing wall.

EFFECT: expanded functionality due to passage of any assemblies through expandable pipes, increased reliability.

3 dwg