US2751019A - Apparatus for disengaging threaded joints - Google Patents

Description

ZJSLM@ June 19, 1956 R. c. BAKER APPARATUS FOR DISENGAGING THREADED JOINTS Filed Feb. 23, 1954 United States Patent f()A -APPARATUS FOR DSENGAGING THREADE JlNTS Reuben C. Baker, Coalinga, Calif., assigner to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of .California Application February 23, 1954, Serial No. 411,771I

6 Claims. (Cl. 166-218) latch sleeve is used to accomplish this purpose, discon? nection between the sleeve and well tool being accomplished by rotating the tubular string.

Specic examples of the foregoing arrangement can be found in my Patent No. 2,644,524, and in my applica-j tion for Non-Rotary Threaded Coupling, Serial No. 172,925, filed July 10, 1950. As disclosed therein, it is desired to effect a threaded connection between a string of tubing and a well packer or casing collar disposed- The packer or collar has a left-handin the manner described above, the disconnection being effected by rotating the tubing string.

At times, after the tubing string has been rotated and disconnected from the well tool, the tubing string,

or at least its lower portion, may move inadvertently in a downward direction, shifting its threaded latch member bac-k into threaded and coupled attachment to the well tool. It then becomes necessary to rotate the tubing string once again to unthread it from the well tool.

It is an object of the present invention to prevent the'l lower portion of the tubular string from inadvertently dropping or moving back into threaded engagement with a well tool disposed in the well bore, after the tubing string has been disconnected fromvthe well tool.

Another object of the invention is to facilitate the unthreading of a tubular string from a well tool disposed in a bore hole.

A further object of the invention is to avoid damage to the threads of a detachable threaded connection while the threads are in meshing engagement, and also after the threaded members have been disengaged from each other.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is' shown in the. drawings accompanying and forming part of the present specification. It will now be described 'in detail, for the purpose of illustrating the general principles of the inventionybut it is tubular body 10 having an upper threaded box 11, which casing B.

to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a combined longitudinal sectional and elevational view of an apparatus disposed in a well casing, with the upper portion of the apparatus attached to a well packer;

Fig. 2 is a View similar to Fig. 1, disclosing the apparatus detached from the well packer;

Fig. `3 is a cross-section, on an enlarged scale, taken along the line 3 3 of Fig. 1.

As disclosed in the drawings, a well tool A, such as a well packer, which may be of the general type disclosed in the above Patent 2,644,524, is disposed in a well It is desired to attach the lower portion of a running-in or tubular string C to the tool, as well as to effect a disconnection of the tubular string from the Well tool Whenever desired.

As specically shown, the well packer A includes a is preferably left-hand. The body of the tool is anchored to the well casing B against movement in both directions. Only a portion of the anchoring device is shown in the drawings, this portion preventing upward movement 0f the well tool within the casing. To accomplish this purpose, an expander 12 is disposed on the body 10 and is adapted to wedge within a set of upper segmental slips 13 that are digging into the wall of the well casing.

A packing sleeve 14 is also disposed around the body 10, having been compressed into leakproof sealing engagement with both the exterior of the body and the wall of the well casing.

Assuming that the well tool or packer A is anchored in packed-olf condition within the well casing, it is desired to secure a string of tubing C thereto, which extends to the top of the well bore. In view of the lefthand threaded box 11 on the body 10 of the well tool, the use of the usual type of left-hand thread on the lower portion of the tubular string would require that the l latter be rotated to the left, in order to effect its threaded connection to the tool body. For the reasons pointed out above, it is not desirable to rotate the tubular string to the left. Accordingly, a latching type of coupling D is secured'to the lower portion of the tubular string C,

- it merely being necessary to stab such lower portion into drawings is also shown in Patent 2,644,524, whereas the specific type is disclosed in above-identied application Serial No. 172,925. The coupling device D, which actually forms the lower end of the tubing string C, in-

v cludes a sub 15a, 15b formed in two parts. An upper sub portion 15a is threaded onto the upper end of a 19 which collectively have a helical male thread 20 provided on their exterior adapted to mate with the internal female thread 21 at the upper end 11 of the packer body. This male thread 20, of course, is left-hand and has the same pitch and lead as the companion female 'thread 21.

One manner of forming the sleeve 16 with its continuous upper portion 17 and depending legs 13 and dogs 19 is to first turn the exterior to the proper diameters,

v and then cut the left-hand thread 20 in its external portion. The external thread conforms to the shape and E diameterof the companion thread 21 on the upper end of the packer body. Thereafter, a plurality of circumferentially spaced, longitudinally extending slots 22 are cut through the sleeve from its lower end to its upper portion 1'7, which remains uncut. This cutting or severing action effectively splits the sleeve and allows its depending legs 1S and dogs 19 to spring inwardly and outwardly. Normally, the dogs 19 remain in the position that they occupy before the slots are cut, to properly meshr with the body box thread 21. However, the dogs 19 may be retracted sufficiently to allow their longitudinal movement into the body without rotation.

In order to allow the dogs 19 to retract to a sufficient extent, so that their threaded portion 2l) clears the thread 21 in the body 10, the exterior of the lower sub portion b is relieved, as by forming a downwardly and inwardly converging portion 23, allowing a clearance space 24 into which the dogs 19 may retract. This relief portion terminates in a retainer or expander portion 25 having a frustoconical external surface diverging in a downward direction and engaging companion surfaces 26 at the lower ends of the dogs 19. rl`he distance between the tapered expander surface 25 and a lower shoulder 27 on the upper sub portion 15a is substantially greater than the length of the sleeve 16 itself, which allows the sleeve to move longitudinally relative to the sub 15a, 15b, for a reason to be described below.

The tubing string C is lowered in the well casing B, with the coupling device D at its lower portion. When the upper end of the packer body is reached, the forward or pilot portion 28 of the lower sub enters the body 1t) until the lowermost thread 20 on the dogs 19 engagesA the companion thread 21 in the body box 11. Such engagement precludes, for the moment, downward movement of the threaded latch sleeve 16 into the body. However, the lower and upper sub portions 15a, 15b continue to move downwardly, moving the retainer and expander portion away from the lower ends 26 of the dogs, and bringing the shoulder 27 at the lower end of the upper sub portion 15a into engagement with the upper end of the sleeve 16. Such engagement enables the upper sub portion 15a to force the sleeve 16 into the body 10.

It is to be noted that the lower surfaces 20a of the dog thread 20 are inclined in a downward and inward direction, so as to function as cams urging the dogs 19 inwardly when engaging the upper portions of the body threads 21. The dogs 19 can retract inwardly, in view of the relief 24 provided behind them by the inclining of the lower sub member surface 23, and by the movement of the retainer 25 away from the lower ends 26 of the dogs 19. Such movement of the sub 15a, 15b and latch sleeve 16 into the body box 11 can occur merely as a result of longitudinal movement of the tubing string C and without its rotation. This downward movement into the packer body will continue until the lower end of the retainer 25 engages a body portion 29 immediately below the thread 21, whereupon the dogs 19 can expand outwardly to their initial position, with their collective external thread 2l) in full mesh with the companion internal thread 21 in the body box 11.

An upward strain can now be taken on the tubing string C, which shifts the upper and lower sub portions 15a, 15b in an upward direction and brings the retainer 25 against the lower tapered ends 26 of the dogs 19. So long as this strain is maintained, the dogs 19 cannot move inwardly, in View of the backing that the retainer 25 provides against them. As a matter of fact, the retainer acts as an expander, urging the dogs in an outward direction, to hold their threaded portion 20 fully meshed with the body box thread 21.

Leakage between the lower sub portion 15b and body 10 may be prevented by mounting suitable side seals 30, in the lower portion of the sub, which engage the inner wall 31 of the body.

When it is desired to disconnect the tubing string C from the well tool A, the former need merely be rotated to the right. This rotational effort or torque is transmitted to the dogs 19 of the latch sleeve 16 through a plurality of longitudinally extending keys 32 which are secured to the lower sub member 15b. These keys 32 extend laterally outward into the slots 22 between ad jacent dogs 19, being engageable with the side surfaces of these dogs, As the sub 15a, 15b is rotated, the turning effort is transmitted through the keys 32 to the dogs 19, turning them within the body box 11 and unthreading the dogs 19 and the sleeve 16 in an upward direction from the latter. The turning effort on the tubing string C to the right is continued until the sleeve dogs 19 have been completely unscrewed from the body 10, whereupon the tubing string may be withdrawn from the well casing B, or elevated therein to the desired extent.

It is quite evident that the tubing string C can be coupled to the body 1G of the well tool merely by moving the former downwardly without rotation within the latter, and that uncoupling can occur as a result of rotating the tubing string to the right. However, under some circumstances, after the sleeve dogs 19 have been completely unscrewed from the body of the tool, the tubing string C, or at least its lower portion, may be inadvertently moved downwardly again, which will have the effect of stabbing the latch sleeve 16 back into the body 1l) and recoupling the tubing string to the body. lt then becomes necessary to rotate the tubing string to the right once again, to etect its uncoupling from the tool A.

The present invention seeks to overcome the foregoing possibility by providing an apparatus E in the tubular string C which will automatically elevate the sub 15a, 15b and latch device 16 away from the threaded body box 11 when the threaded disconnection has taken place. As disclosed in the drawings, the upper sub 15a is threadedly connected to an inner tubular member or mandrel 35 telescopically arranged within an outer tubular member or barrel 36 whose upper portion 37a is threaded onto the lower end of a section of the tubing string C, which extends to the top of the well bore. The inner and outer tubular members 35, 36 are elongated, to enable a substantial amount of relative longitudinal movement between these parts to occur.

The outer tubular member 36 is composed of an upper section 37a threaded into the upper end of a lower section 37b, this lower section terminating in a lower inturned ange or spring seat 38 against which the lower end of a helical compression spring 39 bears, this spring encompassing the inner tubular member or mandrel 35. The upper end of the spring bears upon a spring seat or ange 40 formed on the inner tubular member 35, the latter having a cylindrical peripheral portion 41 extending above the flange 40 which is slidable along the lower inner wall 42 of the upper section 37a of the outer tubular member 36. Leakage from the interior of the tubing string C and upper tubular section 37a and downwardly along the cylindrical periphery 41 of the inner mandrel is prevented, as by providing a suitable rubber seal ring 43, in the form of an O ring, in an internal groove 44 in the upper section adapted to Slidably seal against the cylindrical periphery 41 of the inner mandrel member 35.

The outer tubular member 36 may occupy an upper extended position with respect to the inner mandrel 35, determined by engagement of an intermediate internal stop shoulder 4S on the outer tubular member with the lower end of the mandrel ange 40. When the parts are in this position, the compressed spring 39 is exerting a substantial force on the inner and outer tubular members 35,V 36 tending to elevate the inner member. The outer tubular member 36 may occupy a lower, or collapsed position, relative to the inner tubular member 35, which is determined by engagement of the mandrel ange 40 with a stop shoulder 46 provided by the lower end of the, upper section 37a of the outer barrel 36.

When the parts are in this last-mentioned position, the spring 39 has expanded to a substantial extent, but it is still capable of exerting a force on the inner and outer members 35, 36 tending to hold them in their collapsed or contracted position, such as shown in Fig. `2.

The movement of the inner and outer members 35, 36 with respect to each other is facilitated by minimizing the effect of resistance by fluids that might be disposed between the inner and outer members. Thus, one or more bleeder ports 47 is provided in the outer tubular member 36 immediately below the stop shoulder 46, so as to enable fluids in the annulus 48 between the inner and outer members above the mandrel ange 40 to pass to the exterior of the apparatus upon upward movement of the ange 40 toward the stop shoulder 46. Similarly, one or more bleeder ports 49 is provided in the outer tubular member 36 immediately above the lower spring seat 38, to allow tiuid in the annulus 50 between the inner and outer members below the mandrel flange 40 to move to the exterior of the apparatus, upon relative downward movement of the flange 40 toward the lower spring seat 38.

For the purpose of enabling the rotation of the tubular string C to be imparted to the latch sleeve 16, when the latter is to be unthreaded from the female body thread 21, a slidable spline connection is provided between the inner and outer tubular members 35, 36. Thus, the lower ange 38 of the outer tubular member 36 may have one or more keys 51 secured thereto slidable in elongate slots or keyways 52 in the exterior of the inner member 35. It is evident that rotation of the tubing string C is transferred to the outer tubular member 36, and through the key and keyway connection 51, 52 to the inner tubular member 35, such rotation then being imparted to the sub a, 15b and through the keys 32 to the dogs 19, for the purpose of unthreading the latter in an upward direction from the body 10 of the tool A.

Assuming that the well packer A, or other well tool, has been previously disposed in the well casing B, the telescopic apparatus E with the latching device D mounted on its lower end, is secured to a tubing string section C and the tubing string then lowered in the well casing. In view of the compressive force of the spring 39, the latter will hold the mandrel 35 in an upper position with respect to the outer tubularvmember 36, limited by the engagement of the flange 40 with the upper stop shoulder 46 on the outer barrel 36, this position being disclosed in Fig. 2. The tubing string C and its connecting apparatus E, D forming the lower part thereof are lowered in the well casing B until the latching sleeve 16 is stabbed or shifted downwardly within the body box 11, a threaded connection being secured between the threaded dogs 19 and the box, in the manner described above. If an upward strain is now taken on the tubing string C, assurance is had that the dogs 19 will be retained in threaded engagement with the box thread 21. The taking of a suflicient upward strain on the tubular string C will effect a shifting of the outer barrel 36 upwardly with respect to the inner barrel 35 to the extent determined by engagement of the intermediate stop shoulder 45 with the mandrel ange 4t) (Fig. l). With the parts in this position, the spring 39 has been compressed to a substantial extent.

lt is to be noted that with the telescopic parts occupying their collapsed position shown in Fig. 2, or their extended position disclosed in Fig. l, the seal ring 43 is continuously in contact with the cylindrical periphery 41 of the mandrel 35, to prevent fluid from leaking out of the apparatus through the telescopic joint. Fluids may now pass in either an upward or a downward direction through the tubular string C and the packer device A vwithout fear of its leaking from the apparatus.

lt' it is desired to disconnect the tubular string C from the well tool A, the tubular string is rotated to the right, the tubular string first preferably being elevated, so as to etect a compression of the spring 39. The rotation of the tubular string is transmitted to the outer barrel 36, through the key and keyway connection 51, 52 to the inner mandrel 35, and from the latter through the sub 15a, 15b to the keys 32 and the dogs 19, rotating the dogs and unscrewing the latter from the body box 11. As the unthreading action occurs, the latching sleeve 16 and the mandrel sub 15a, 15b, as well as the mandrel 35 itself, move in an upward direction, this action being assisted by the expansion of the compression spring 39. Finally, the dog threads 20 will be completely disengaged from the box thread 21. When this occurs, the spring can expand promptly to its fullest extent, lifting the latching sleeve 16 completely out of the threaded body portion 11 and a substantial distance above the latter (Fig. 2). The spring 39 maintains the mandrel 35, sub 15a, 15b, and threaded latch sleeve 16 in such an upward position, and precludes inadvertent dropping of the sub 15a, 15b and latch sleeve 16 back into threaded engagement with the female thread 21 of the box 11.

The tubing string C, with the inner and outer tubular members 35, 36, sub 15a, 15b and latch sleeve 16 connected thereto, may now be elevated in the casing B and withdrawn from the well bore, if desired. On the other hand, they can be moved down in the casing to recouple the threaded dogs 19 to the body thread 21, if this is desired.

With the arrangement disclosed, the unthreading of the dogs 19 from the body 10 of the well tool is facilitated, since the spring is constantly urging the inner mandrel 35 and the lower parts attached thereto in an upward direction, which is the direction in which the parts are being moved by the latch sleeve 16 when being unscrewed from f the body box 11. In addition, damage to the threads is avoided, since the detachment of the latch sleeve from the uppermost thread of the box immediately allows the spring 39 to expand and elevate the latch sleeve Well 16 above the box thread 21, and prevents any possibility of v the continued rotation of the tubing string to cause the lowermost latch sleeve thread 20 to rotate along and bounce upon the uppermost body thread 21. Undue strain on the threads 20, 21 is avoided, since the rotation of the tubing string causes a substantially immediate elevation of the mandrel flange 40 above the intermediate stop shoulder 45, the only force exerted between the threads being that due to the compression spring 39, which force actually decreases as unthreading proceeds. In the absence of the device, it is diicult to gauge the upward strain that must be taken on the tubing string C to effect unthreading of the latch sleeve` 16 from the box thread 21. Thev tendency is to take too great a strain on the tubing string, which may produce thread damage in and of itself.

The inventor claims:

1. In subsurface apparatus: a well tool having a thread; an upper member attachable to a running-in string; a lower member telescopically related to said upper member; expansible and retractable latch means carried by and movable laterally of said lower member, said latch means having a thread companion to said well tool thread and engageable therewith, said latch means being movable laterally in one direction on said lower member into threaded engagement with said well tool thread and laterally in the other direction on said lower member to an extent suicient to position said threads out of engagement with each other to enable said latch means to be moved longitudinally and without rotation past said well tool thread; means providing a connection between said lower member and latch means for transmitting rotary motion therebetween; means providing a connection between said upper and lower members for transmitting rotary motion therebetween; and means urging said lower member and latch means in an upward direction relative to said upper member.

2. n subsurface apparatus: a well tool having a thread;

an upper member attachable to a running-in string; a lower member telescopically related to said upper member; eX- pansible and retractable latch means carried by and movable laterally of said lower member, said latch means having a thread companion to said well tool thread and engageable therewith, said latch means being movable laterally in one direction on said lower member into threaded engagement with said well tool thread and laterally in the other direction on said lower member to an extent suicient to position said threads out of engagement with each other to enable said latch means to be moved longitudinally and without rotation past said well tool thread; means providing a connection between said lower member and llatch means for transmitting rotary motion therebetween; means providing a connection between said upper and lower members for transmitting rotary motion therebetween; and spring means acting between said members for urging said lower member and latch means in an upward direction relative to said upper member.

3. In subsurface apparatus: a well tool having a thread; an upper member attachable to a running-in string, a lower member telescopically related to said upper member; expansible and retractable latch means carried by and movable laterally of said lower member, said latch means having a thread companion to said well tool thread and engageable therewith, said latch means being movable laterally in one direction on said lower member into threaded engagement with said well tool thread and laterally in the other direction on said lower member to an extent sufficient to position said threads out of engagement with each other to enable said latch means to be moved longitudinally and without rotation past said well tool thread; means providing a connection between said lower member and latch means for transmitting a rotary motion therebetween; means providing a connection between said upper and lower members for transmitting rotary motion therebetween; and a compression spring engaging said members to urge said lower member and latch means in an upward direction relative to said upper member.

4. In subsurface apparatus: a well tool having a female thread; an upper member attachable to a running-in string; a lower member telescopically related to said upper member; expansible and retractable latch means carried by and movable laterally of said lower member, said latch means having a male thread engageable with said female thread, said latch means being retractable on said lower member to the extent in which the effective outer diameter of said male thread is .less than the inner diameter of said female thread; means providing a connection between said lower member and latch means for transmitting rotary motion therebetween; means providing a connection between said upper and lower member for transmitting rotary motion therebetween; and means urging said lower member and latch means in an upward direction relative to said upper member.

5. ln subsurface apparatus: a well tool having a female thread; an upper member attachable to a running-in string; a lower member telescopically related to said upper member; expansible and retractable latch means carried by and movable laterally of said lower member, said latch means having a male thread engageable with said female thread, said latch means being retractable on said lower member to the extent in which the effective outer diameter of said male thread is less than the inner diameter of said female thread; means providing a connection between said lower member and latch means for transmitting rotary motion therebetween; means providing a connection between said upper and lower members for transmitting rotary motion therebetween; and a compression spring engaging said members to urge said lower member and latch means in an upward direction relative to said upper member.

6. In subsurface apparatus: a well tool having a female thread; an upper member attachable to a running-in string; a lower member telescopically related to said upper member; expansible and retractable latch means carried by and movable laterally of said lower member, said latch means having a male thread engageable with said female thread, said latch means being retractable on said lower member to the extent in which the etfective outer diameter of said male thread is less than the inner diameter of said female thread; means providing a connection between said lower member and latch means for transmitting rotary motion therebetween; means providing a connection between said upper and lower members for transmitting rotary motion therebetween; a compression spring engaging said members to urge said lower member and latch means in an upward direction relative to said upper member; and seal means between said upper and lower members to prevent fluid from passing from the interior of said members to the exterior of said members both when said members are in fully contracted and fully extended positions with respect to each other.

References Cited in the le of this patent UNITED STATES PATENTS 2,262,117 Roe Nov. ll, 1941 2,318,167 Knowlton May 4, 1943 2,644,524 Baker July 7, 1953

Claims (1)

1. IN SUBSURFACE APPARATUS: A WELL TOOL HAVING A THREAD; AN UPPER MEMBER ATTACHED TO A RUNNING-IN STRING; A LOWER MEMBER TELESCOPICALLY RELATED TO SAID UPPER MEMBER; EXPANSIBLE AND RETRACTABLE LATCH MEANS CARRIED BY AND MOVABLE LATERALLY OF SAID LOWER MEMBER, SAID LATCH MEANS HAVING A THREAD COMPANION TO SAID WELL TOOL THREAD AND ENGAGEABLE THEREWITH, SAID LATCH MEANS BEING MOVABLE LATERALLY IN ONE DIRECTION ON SAID LOWER MEMBER INTO THREADED ENGAGEMENT WITH SAID WELL TOOL THREAD AND LATERALLY IN THE OTHER DIRECTION ON SAID LOWER MEMBER TO AN EXTENT SUFFICIENT TO POSITION SAID THREADS OUT OF ENGAGEMENT WITH EACH OTHER TO ENABLE SAID LATCH MEANS TO BE MOVED LONGITUDINALLY AND WITHOUT ROTATION PAST SAID WELL TOOL THREAD; MEANS PROVIDING A CONNECTION BETWEEN SAID LOWER MEMBER AND LATCH MEANS FOR TRANSMITTING ROTARY MOTION THEREBETWEEN; MEANS PROVIDING A CONNECTION BETWEEN SAID UPPER AND LOWER MEMBERS FOR TRANSMITTING ROTARY MOTION THEREBETWEEN; AND MEANS URGING SAID LOWER MEMBER AND LATCH MEANS IN AN UPWARD DIRECTION RELATIVE TO SAID UPPER MEMBER.

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