RU2266387C1 - Borehole casing spear - Google Patents

Abstract

FIELD: fishing for or freeing objects in boreholes or wells, particularly used during tube damage liquidation inside wells.

SUBSTANCE: spear comprises conical body with guiding means in lower part and sub in upper part thereof, fishing bush and releasing unit. The fishing bush is made as collet provided with slips in lower part thereof and with rest in upper part thereof. The rest has guiding pin fixedly secured to it. Releasing unit is made as figured channel formed on outer surface of conical body. The channel includes alternating short and long groves adapted to cooperate with guiding pin to rotate thereof only in one direction relative conical body when collet reciprocates relative the conical body.

EFFECT: increased structural reliability and possibility to perform all operations under control, increased reliability of spear freeing.

2 dwg

Description

The invention relates to fishing devices used to eliminate accidents with pipes in wells, and in particular to emergency tools used to extract pipes from a well by trapping them on the inner surface.

Known internal releasing tube (AS No. 1559106, E 21 B 31/20, 1986, publ. BI No. 15 of 04/23/1990), comprising a housing with a spiral conical surface, a connecting thread at the upper end and a guide a tip on the bottom, a gripping sleeve with a spiral conical surface on the inner surface of the reciprocal spiral conical bearing surface of the housing and a threaded thread on the outer surface, cylindrical clips placed above and below the gripping sleeve, guides evenly spaced in longitudinal planes around the circumference of the body, the gripping sleeve is made in the form of separate segments, the ends of which are made in the form of T-shaped protrusions and placed in clips with the possibility of limited radial movement, while the guides are placed between the segments of the gripping sleeve, and cylindrical clips are installed with the possibility of limited axial movement, and the upper cylindrical cage interacts with the housing by means of a spring placed above it.

The disadvantages of this design are:

firstly, the complexity of manufacturing, due to the large number of technically complex parts, which leads to an increase in the cost of the structure as a whole and as a result of its high cost;

secondly, a large number of parts in contact with each other in the process of catching the emergency string, leads to low reliability of the device when working in difficult conditions (large depth and curvature of the well);

Closest to the proposed technical solution is a borehole tube (AS No. 956745, E 21 B 31/20, 1982, publ. BI No. 33 of 09/07/1982), containing a conical body with a guide in the lower part and sub at the top, a conical fishing sleeve and a release unit, which is made in the form of flexible elements, some ends of which are connected to the fishing sleeve, and others to the sub.

The disadvantage of the downhole tube is a high probability of an accident due to:

firstly, low reliability in the work of flexible elements, which can lead to their breakage, as well as to a violation of their fastening from above with a sub, and from below with a fishing sleeve;

secondly, the lack of control of the entry of the dies of the fishing sleeve into the pipe, which leads to the unloading of the tube, lowered on the work string to the upper end of the emergency pipes, as a result of which the bent flexible elements can be destroyed.

In addition, the release of the tube from the seized emergency pipes occurs first by abruptly landing the pipe down and then rotating, as a result of which the flexible elements are wound onto the body, reducing in length, while the dies of the fishing sleeve come out of the stuck state with the inner wall of the emergency pipes, which leads to to the impossibility of winding the flexible element, as a result, when the dies rise, the wedges again jam, which makes it impossible to release the tube from the emergency pipes.

An object of the invention is to increase the reliability of the design, as well as monitoring the ongoing technical operations and guaranteed release of the tube in case of impossibility to remove the stuck emergency pipes.

The specified technical problem is solved by the proposed tube containing a conical body with a guide in the lower part and an sub in the upper, fishing sleeve and release unit.

What is new is that the fishing sleeve is made in the form of a collet equipped with slips from below and a stop with a rigidly connected guide pin from above, while the release unit is made in the form of a figured groove on the outer surface of the conical body with alternating short and long longitudinal grooves, which are made with the possibility of interaction with the guide pin to rotate it in only one direction relative to the conical body with reciprocating movement of the collet relative to the conical body a.

Figure 1 shows the proposed borehole inner tube.

Figure 2 shows a partial scan of the released node borehole inner tube.

The device consists of a conical body 1 (see Figure 1) with a guide 2 in the lower part and an adapter 3 in the upper part, a fishing sleeve 4 and a release unit 5. The fishing sleeve 4 is made in the form of a collet 6, provided with bottom slips 7, and on top - focus 8 with a rigidly connected guide pin 9. The release unit 5 is made in the form of a figured groove 10 (see Figure 2) on the outer surface of the conical body 1 with alternating short - length L and long - length L1 longitudinal grooves, which are made with the possibility interactions with guide pins Volume 9 to rotate it in one direction only relative to the conical body 1 (see FIG. 1) for reciprocal movement relative to the collet 6 of the conical body 1.

The tube works as follows.

The tube in the transport position (see Figure 1) on the column of working pipes 11 through the sub 3 is lowered into the well to the upper end of the emergency pipes 12, while the guide pin 9 (see Figure 2) is placed in a short longitudinal section of the figured groove 10 ( see pos.13) of the release unit 5. The tube is gradually lowered into the emergency pipes 12 (see Figure 1) due to the guide 2 until the upper end of the emergency pipes 12 abuts against the lower end of the stop 8 (catch "stop" ), while the slips 7 of the fishing sleeve 4 do not contact the inner wall of the emergency column 12 .

After that, the tube is raised by about 1 meter and lowered again, as a result, the guide pin 9 (see Figure 2) moves from a short longitudinal groove of length L (see pos. 13) to a long longitudinal groove of length L1 (see pos. 14), occupying the working position, while the slips 7 (see Figure 1) begin to contact the inner wall of the emergency pipes 12 due to wedging of the collet 6 by the conical body 1. If the emergency pipes 12 are not stuck on the bottom of the well (not shown in FIG. ), then they, together with the tube, are raised to the surface. If the emergency pipes 12 are seized, then restore circulation through the Central channel 15 of the conical housing 1 and try to remove the emergency pipes 12.

If it is impossible to remove the emergency pipes 12, the tube is released from them, while the tube on the column of working pipes 11 is lowered down, that is, unloaded to the bottom, then lifted up about 1 meter, and again lowered, with such actions, the guide pin 9 (see Figure 2) moves from a long longitudinal groove of length L1 (see pos. 14) to a long short groove of length L (see pos. 13), moving the tube from the working position to the transport one, in which the slips 7 do not contact the internal surface of the emergency pipe 12. Further, the pipe ekayut from the well.

Thanks to the use of the proposed pipe, the reliability of the structure is increased, it becomes possible to monitor the ongoing technical operations, as well as guaranteed release of the pipe if it is not possible to remove the stuck emergency pipes.

Claims (1)

A downhole inner tube containing a conical body with a guide in the lower part and an adapter in the upper one, a fishing sleeve and a release unit, characterized in that the fishing sleeve is made in the form of a collet equipped with bottom slips and a stop with a rigidly connected guide pin on top, while the assembly the release is made in the form of a figured groove on the outer surface of the conical body with alternating short and long longitudinal grooves, which are made with the possibility of interaction with the guide pin for its rotation only in one direction relative to the conical body during the reciprocating movement of the collet relative to the conical body.

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