DEVICE FOR CUTTING A PORTION OF A CASING STRING IN A WELL Russian patent published in 2019 - IPC E21B29/00 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and mining industry and can be used to cut a portion of a casing string in a well. Device comprises a body with a limiter in the form of an annular protrusion, centralizer and grooves, extension boring tools hinged in the grooves. Radial channels are made in the body in the plane of the extension of the boring tools and are directed to the cutting zone. Hydraulic drive is placed in the annular cavity of the body above the boring tools and is made in the form of a hollow piston with a collar at the top and is equipped with a choke. Three radial channels, hermetically sealed with a hollow bushing, are made above the limiter, made with a saddle under the ball and with the possibility of axial movement down under the action of excess hydraulic pressure in the cavity of the device and fixation in the body. At the lower end of the inner wall of the hollow piston there is an annular protrusion. In the cavity of the piston with the possibility of axial movement and fixation from moving down there is the upper end of the hollow cylinder. Internal diameter of the cylinder is more than internal diameter of the choke. Lower end of the cylinder is made with a tapered end that interacts with the boring tools. Cylinder passes through the opening of the annular partition on the inner side wall of the annular cavity of the body. Above the partition there is a compression spring holding the piston with the cylinder in its extreme upper position. Under the partition on the outer side wall of the cylinder there is a ring lug. Cylinder is spring-loaded by a compression spring. Compression spring located above the body partition wall has an elastic force that is greater than the elastic force of the compression spring located under the partition wall.

EFFECT: expanded technological capabilities of the device due to its use for cutting pipes at different depths.

1 cl, 2 dwg