RU2354805C1 - Casing spear - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil and gas industry and is intended for withdrawal of emergency pipes from wells. Device comprises hollow body with internal cone surface in lower part, sub installed in hollow body, central core with aligning cone, coaxially installed in hollow body and having common axial channel, external gripping element and internal gripping element installed in hollow body with the possibility of axial displacement, slotted nut that is rigidly fixed to internal cavity of hollow body in its upper part and connected to central core by means of slotted joint that provides for rotation of hollow body together with central core relative to device axis, distance sleeve installed on external gripping element, cone piston installed on central core under slotted nut and resting on distance sleeve. Hollow body in lower part contains external aligning cone with cutters on its internal cone surface. Central core in its upper part is rigidly connected to sub installed with the possibility of rotation, and has annular bulge with radial holes that provide for creation of annular cavity between slotted nut and cone piston, and this cavity is hydraulically connected to common axial channel. External gripping element is installed in internal cone surface of hollow body and is arranged in the form of split bushing with ribbed internal surface and cone external surface. Internal gripping element is installed on central core between cone piston and aligning cone and is arranged in the form of split bushing with ribbed external surface and internal surface in the form of meeting upper and lower cones. Surface of upper cone is responsive to external cone surface of cone piston, and lower one - to external cone surface of aligning cone. Aligning cone is equipped with cutters in lower part.

EFFECT: increased operational reliability and expansion of technological resources.

1 dwg

Description

The invention relates to a fishing tool and is designed to extract from the wells emergency drill and tubing, as well as other hollow cylindrical objects.

Analysis of the existing level showed the following:

- a tube is known that includes a hollow body with an inner conical surface in the lower part, a sub located on the hollow body, a central core with a centering cone (rod) coaxially mounted in the hollow body and having a common axial channel, an external gripping element and an internal gripping element ( collet grips) installed in a hollow housing with the possibility of axial movement (see AS No. 389239 dated June 24, 71 according to class E21B 31/02, published in OB No. 29, 1973).

The disadvantage of this device is the low operational reliability of the device due to the following reasons:

- collet grips provide gripping of the pipe only at the collet locations, while the small contact area of the collets with the pipe will not provide a reliable grip of the pipe string of large weight;

- collet grips, located opposite each other, can cut the metal of pipes that are in the gripping places of the collets, without providing their rise;

- due to the impossibility of regulating the gripping force, which depends only on the weight of the pipe string, the tube will not provide the lifting of pipes of small weight;

- it is impossible to capture pipes with flanged edges or other similar defects, because for their capture, it is necessary to conduct appropriate preparation of the ends of the pipes for their passage through the annular space of the tube.

As a prototype, a downhole tube including a hollow body with an inner conical surface in the lower part, a sub located on the hollow body, a central core with a centering cone (rod with a conical tip), coaxially mounted in the hollow body and having a common axial channel, is taken externally an element and an internal gripping element (collet grips) installed in a hollow housing with the possibility of axial movement (see AS No. 901471 of 04/17/80 according to class E21B 31/16, published in OB No. 4, 1982 .).

The disadvantage of this device is the low operational reliability of the device, due to several reasons:

- collet grips ensure the capture of the emergency pipe only at the locations of the collets, the small contact area of the collets with the emergency pipe reduces the reliability of the capture and increases the shear stress;

- the location of the collet grips with axial displacement eliminates the possibility of bending the pipes with a small weight of the column, which reduces the reliability of the capture of pipes and increases the possibility of cutting metal pipes in the places of capture;

- the dependence of the gripping force on the weight of the pipe string and the impossibility of its regulation will not allow to remove pipes and other hollow cylindrical objects of small weight;

- it is impossible to capture the emergency pipe with bent and wrinkled edges due to the impossibility of their milling.

The technical result that can be obtained by carrying out the invention provides an increase in the operational reliability of the device and the expansion of technological capabilities due to:

- guaranteed capture of emergency pipes regardless of their weight by increasing the contact area of the external and internal exciting elements with the emergency pipe;

- regulation of the gripping force by providing regulation of the pressure of the working fluid;

- preliminary milling of bent and crumpled pipe edges, achieved by rotation of the hollow body with an external centering cone and the central core with a centering cone, equipped with cutters.

The technical result is achieved using a known device comprising a hollow body with an inner conical surface in the lower part, a sub located on the hollow body, a central core with a centering cone, coaxially mounted in the hollow body and having a common axial channel, an external gripping element and an internal gripping element mounted in a hollow housing with the possibility of axial movement,

According to the invention, the tube further comprises a spline nut rigidly connected to the inner surface of the hollow body in its upper part and connected to the central core by means of a spline connection that rotates the hollow body together with the central core relative to the axis of the device.

A spacer sleeve mounted on an external gripping element and a conical piston mounted on a central core under a spline nut and supported by a spacer sleeve.

The hollow body in the lower part contains an external centering cone with cutters on its inner conical surface.

The central core in the upper part is rigidly connected with the sub mounted for rotation and has an annular protrusion with radial holes, which provides the formation between the spline nut and the conical piston of the annular cavity, hydraulically connected with a common axial channel.

An external gripping element is mounted on the inner conical surface of the hollow body and is made in the form of a split sleeve with a ribbed inner surface and a conical outer surface.

The inner gripping element is mounted on the central core between the conical piston and the centering cone and is made in the form of a split sleeve with a ribbed outer surface and an inner surface in the form of converging upper and lower cones, the surface of the upper cone being the counter outer conical surface of the conical piston and the lower one being the outer conical surface of the centering cone. The centering cone in the lower part is equipped with incisors.

Thus, the claimed technical solution meets the criterion of novelty.

The analysis of the inventive step showed the following: from the sources of patent documentation and scientific and technical literature, we have not identified technical solutions that are based on features that match the distinctive features of the claimed technical solution. The technical result achieved is due to the unknown properties of the structural elements and the hydraulic connections of the device, ensuring guaranteed capture of emergency pipes regardless of their weight, the ability to control the gripping force and the possibility of preliminary milling of bent and wrinkled pipe edges. Thus, the essential features claimed by us do not follow explicitly from the analyzed prior art, i.e. correspond to the condition of inventive step.

The drawing shows a longitudinal section of the proposed device.

The inventive device comprises a hollow body 1, in the lower part having an inner conical surface 2. On the hollow body 1 is a sub 3 with the possibility of rotation. In the hollow body 1, a central core 4 is coaxially mounted, in the upper part it is rigidly connected to the sub 3 and in the lower part with a centering cone 5. In the lower part, the centering cone 5 is equipped with cutters 6. The central core 4 and the centering cone 5 have a common axial channel 7 A slotted nut 8 is screwed into the upper inner part of the hollow body 1, connected to the central core 4 by means of a spline connection, which rotates the hollow body 1 together with the central core 4. Under the spline nut 8, the central core 4 has t annular protrusion 9 with the radial openings 10. The lower part of the hollow body 1 is rigidly connected with the outer centering cone 11, the internal cone surface of which is provided with cutters 12. The inner conical surface 2 of the hollow body 1 is mounted an outer gripping element 13 is axially displaceable. The external gripping element 13 is made in the form of a split sleeve with a ribbed inner surface and a tapered outer surface. A spacer sleeve 14 is installed on the external picking element 13. A conical piston 15 is mounted under the spline nut 8 on the central core 4 and is supported by the spacer sleeve 14. The annular protrusion 9 forms an annular cavity 16 hydraulically connected between the spline nut 8 and the conical piston 15 radial holes 10 with a common axial channel 7. On the central core 4, between the conical piston 15 and the centering cone 11, an internal gripping element 17 is installed with the possibility of axial movement. The internal gripping element is made in the form of a split sleeve with a ribbed outer surface and an inner surface in the form of converging upper and lower cones. The surface of the upper cone is the mating outer conical surface of the conical piston 15, and the lower one is the outer conical surface of the centering cone 11.

The device operates as follows.

The tube on the drill pipe string is lowered into the well. When the centering cone 11 reaches the upper end of the emergency pipe, it enters the latter. If necessary, preliminary milling of the bent or wrinkled edges of the emergency pipe drill pipe string begin to rotate. In this case, the rotation through the sub 3 is transmitted to the central core 4 and then through the spline connection to the slotted nut 8, ensuring the rotation of the hollow body 1. When the central core 4 and the hollow body 1 rotate, the pipe edges are milled by means of cutters 6 of the centering cone 5 and cutters 12 of the outer centering cone 11. With a further lowering of the tube, the emergency pipe moves between the outer gripping element 13 and the inner gripping element 17 all the way into the conical piston 15. Further, the rotation of the they rotate and feed the working fluid into the tube, which through the axial channel 7 and the radial holes 10 enters the annular cavity 16, creating pressure on the conical piston 15. The tube is lifted, while the conical piston 15 moves downward under the action of the pressure of the working fluid. The outer gripping element 13 is lowered along the inner conical surface 2 of the hollow body 1, while moving in the transverse direction. The internal gripping element 17 also moves in the transverse direction, as a result of which there is a guaranteed capture of the emergency pipe over the entire contact surface of the external and internal gripping elements 13, 17 with the extracted pipe. The ability to control the gripping force by changing the pressure of the working fluid allows you to remove pipes of both small and large weights. After depressurizing and unloading the tube, the elastic forces of the external and internal gripping elements 13.17 return the cone piston 15 and the central core 4 with the centering cone 5 to their original position, freeing the emergency pipe.

Thus, we can conclude that the proposed technical solution meets the criterion of industrial applicability.

The present invention meets the condition of patentability, as it is new, has an inventive step and industrial applicability.

Claims (1)

A tube containing a hollow body with an inner conical surface in the lower part, a sub located on the hollow body, a central core with a centering cone, coaxially mounted in the hollow body and having a common axial channel, an external gripping element and an internal gripping element installed in the hollow body with the possibility of axial movement, characterized in that it further comprises a spline nut rigidly connected to the inner surface of the hollow body in its upper part and associated with the price by means of a spline connection, providing a rotation of the hollow body together with the central core relative to the axis of the device, a spacer sleeve mounted on the external gripping element, and a conical piston mounted on the central core under the spline nut and resting on the spacer sleeve, while the hollow body is in the lower part contains an outer centering cone with incisors on its inner conical surface, and the central core in the upper part is rigidly connected to the sub, Rotated, it has an annular protrusion with radial holes that provide an annular cavity between the spline nut and the conical piston, hydraulically connected to the common axial channel, while the external gripping element is mounted on the inner conical surface of the hollow body and is made in the form of a split sleeve with with a ribbed inner surface and a conical outer surface, and an internal gripping element mounted on a central core between the conical piston and the center the cone and is made in the form of a split sleeve with a ribbed outer surface and an inner surface in the form of converging upper and lower cones, the surface of the upper cone being a mating outer conical surface of the conical piston and the lower cone of the outer conical surface of the centering cone, while the centering cone in the lower parts equipped with cutters.