US2806536A - Well packer - Google Patents

Description

WELL PACKER Sept. 17, 1957 R. C, BAKER ErAL 2,806,536

WELL PACKER United States Patent WELL PACKER Reuben C. Baker, Coalinga, and Martin B. Conrad, Downey, Calif., assignors to Baker Oil Tools, line., Les Angeles, Calif., a corporation of California Application April 27, 1953, Serial No. 351,382

13 Claims. (Cl. 166-123) The present invention relates to packers capable of performing various operations in oil and gas wells, such as cementing, acidizing, testing, production and swabbing.

An' object of the present invention is to provide an improved well packer connectible to a tubular string, and particularly adapted to control ow of fluid between the interior of the tubular string and the annulus above the packer between the tubular string and a surrounding well casing.

Another object of the invention is to provide a well tool embodying an improved releasable lock device for preventing normally retracted means, such as slips, from being expanded outwardly against the wall of a conning well casing, in which the tendency for the lock device to be released inadvertently is greatly minimized, if not completely eliminated.

A further object of the invention is to provide a subsurface well tool connectible to a tubular string, whose operation is controlled by a drag device frictionally engageable with the wall ofthe well casing, or similar well conduit, in which thetubular string is selectively rotatable in the well bore without tending to rotate the drag device.

Yet another object of the invention is to provide a well tool embodying a central body or mandrel and a releasable lock device for preventing normally retracted means, such as slips, from being expanded outwardly against the wall of a confining well casing to anchor the body or mandrel therewithin, in which a safety device is available to effect removal of the body from the remainder of the tool in the event the normally retracted means cannot be retracted, or otherwise released, from the casing.

This inve-ntion possesses many other advantages, and has other objects which may be made more clearly kapparent 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 invention; but it is to be understood that such4 detailed description is not to be taken in a limiting sense, since the scope of the invention is best dened by the appended claims.

Referring to the drawings:

Figure l is a side elevation of a well packer embodying the invention;

Fig. 2 is a longitudinal section through the well packer shown in Fig. 1, with parts in retracted position;

Fig. 3 is a View similar to Fig. 2, with the well packer parts expanded against the well casing;

lFig. 4 is a fragmentary longitudinal section disclosing the operation of one of the safety joints;

l Fig. 5 is a cross-section taken along the line 5-5 on Fig. 3;

. Fig. 6 is a section taken along the line 6-6 on Fig. 3.

The well packer A disclosed in the drawings is of the type adapted to be run in a well casing B on a string of Cil tubing C, to be anchored'in packed-olf condition in the well casing, preferably against downward movement therewithin. The well packer also' embodies a control valve portion for determining the flow of fluid between the interior of the tubular string C and packer A and the annulus D above the packer between the tubular string C and the well casing B.- V

The well packer includesl a central tubular body or mandrel 10, which is disclosed as consisting of an upper section 11 suitably secured to a lower section 12, as through the use of welding material 13.` The upper section has a threaded box 14 for the reception of a threaded pin 15 at the lower end of an adjacent section of the tubular string C. 'v The body 10 extends throughout the entire length of the well packer device, and may have tubular tailpipe, or other tubing (not shown) connected to its lower end 16, for extension to a predetermined lower location in the well casing. Any tubing depending from the body should not have an outside diameter that is greater than the outside diameter of t-he body 10 itself.

A plurality of slips 17 is provided to anchor the body 10 to the well casing against downward movement therewithin. These slips have external Wickers 18 facing predominantly in a downward direction, to dig into the wall of the well casing B and preclude their downward movement. The slips 17 are urged in a radial outward direction. and also in a radial inward direction, by a tapered expander 19 slidable relatively on the body and disposed within the slips. This expander has downward and inwardly tapering surfaces 20 engageable with companion surfaces 21 on the slips, for the purpose of expanding the slips in an outward direction whenever the slips and expander move longitudinally towardv each other. Each slip 17 has a positive connection with the expander 19, to secure retraction of the slips when the expander and slips move in longitudinal directions away from each other. As disclosed, such positive connection is effected by pro'- viding tongues 22 on the opposed sides of the inner portions of each slip slidable in opposed companion grooves 23 in the expander. p

ln addition to anchoring the body 10 to the well casing B, it is desired to effect an annular seal between the body and the well casing. Such seal can be provided by a packing structure 24. As disclosed in the drawings, this structure includes a rubber, or rubber-like, packing sleeve 25 surrounding the body 10 and havingits upper and lower ends 26, 27 piloted within upper and lower rings 28, 29 to which the upper and lower ends of the packing are permanently'secured by a molding operation. The lower ring 29 is threaded into a lower gauge ring 30, which is, in turn, threaded onto the upper end ofthe tapered expander 19; whereas the upper ring y28 is threaded into an upper gauge ring 31, whichris, inturn, threaded onto the lower end of an upper valve head and packing actuating member 32 surrounding the body 10.

The upper portion of this valve head member 32 is provided with a counterbore 33, the lower portion 34 of which forms an axial seat for a seal ring 35 contained in a groove 36 in a head 37 extending outwardly from the upper body section 11. The wall 38 of the counterbore forms a cylindrical seat forthe reception of the periphery of the llangeor head 37,-and for sealing engagement with a side seal 39, i-n the formv of a rubber, or rubber-like, O ring confined within a groove 40 in the periphery of the ange 37. When the flange 37 is in an upward position out of its seat 38, generally radial ports 41 extending through the body 1t) afford communication between the interior of the body and the exterior of the body above the valve head member 32. Y When the body 10 is moved downwardly Yin the valve head Patented Sept. 1,9577

3 member 32, so as to engage the seal rings 35, 39 with their companion seats 34, 38, then the passages through the ports 41 are closed.

The' upper body section 11 is releasably connected to the valve head and packing actuating member 32. by means of an upper safety joint. Thus, the upper section 11 has external left-hand threads 42 engaging internal lefthand threads 43 in a threaded sleeve 44 disposed within an enlarged bore 45 in the lower portion of the Valve head member 32. A longitudinally extending key 46 is welded, or otherwise suitably secured, to the exterior of the safety sleeve 44, and this key is slidable in a companion keyway 47 formed in the valve head member 32. The lower end of the sleeve 44 is initially spaced a substantial distance above a bridge ring 48, which engages the upper end of the packing sleeve 25, and which extends between the periphery of the body or mandrel and the lower portion of the valve head member 32, so as to prevent the packing sleeve from moving upwardly into the lower counterbore of the member 32. This ring 48 is precluded from moving upwardly with respect to the valve head member 32 by engaging a suitable shoulder 49 therein.

The slips 17 are all connected together for joint longitudinal movement. Thus, each slip has a pin 50 connected to the upper end of a link 51 that has its lower end provided with a radial hole 52 loosely receiving a radial pin 53 secured to a slip ring 54 attached to the upperend of a ratchet or coupling collar 55 forming the outer portion of a releasable lock or latch device that controls the operation of the well packer. The slip ring 54 may be secured to the collar 55 by one or more screws 56. As shown in the drawings, this collar surrounds the lower portion of a ratchet sleeve 57 having longitudinally spaced circumferential ratchet teeth 58 facing in a downward direction, the upper end of this sleeve having an internal left-hand thread 59 receiving a companion external left-hand thread 60 on the lower body section 12. Inadvertent unthreading of the external thread 60 from the internal thread 59 is initially precluded by a suitable shearscrew 61, or other frangible device, threaded to the upper end of the ratchet sleeve 57 and into the lower body section 12. Y

The ratchet sleeve 57 is provided with a longitudinal slot or keyway 62, in which a key 63 is slidable. This key extends radially and engages one end 64 of an expansible and contractible split ratchet sleeve 65 disposed within the ratchet collar 55, this sleeve possessing internal teeth 66 facing in an upward direction and adapted to mesh with the external ratchet teeth 58 on the ratchet sleeve 57. The other end 67 of the sleeve 65 is engageable with a key or stop 68 secured within a groove 69 in the ratchet collar 55. The exterior of the split ratchet sleeve 65 is `provided with longitudinally spaced circumferential cam teeth 70 having cam surfaces 71 tapering in a downward and inward direction and engageable with companion longitudinally spaced cam teeth 72 in the collar having surfaces 73 also tapering in a downward and inward direction.

The split ratchet sleeve 65 normally contracts to place its ratchet teeth 66 in engagement with the sleeve ratchet teeth 58. When this occurs, the body 10 is connected to the collar 55 and cannot move downwardly with respect thereto, although the body 10 can ratchet freely up through the catchet sleeve 65. Any Vtendency for the ratchet sleeve 65 to disconnect from the body 10 is prevented by the coengagement of the cam teeth 70, 72, which urge the ring or sleeve 65 in Van inward direction. When it is desired to move the body 10 in a downward direction with respect to the ratchet collar 55, for the purpose of expanding the slips 17 and the packing sleeve 25 outwardly against the well casing B, the tubular string C and the body 10 connected thereto are turned to the right, or in a clockwise direction, as seen from the top of the well hole, and when the ratchet collar 55 is prevented from rotation, as described hereinbelow, such turning causes a corresponding turning of the ratchet sleeve 57 and of the key 63, the key engaging one end 64 of the split ratchet sleeve member 65. Since its other end cannot move because it engages the stationary stop 68, the sleeve 65 is expanded to bring its teeth 66 out of engagement with the ratchet sleeve teeth 58. This then allows the body 10 to be lowered within the ratchet collar 55. The parts 55, 57, 58 and 62 to 73, inclusive, constitute a lock device for selectively permitting or preventing relative longitudinal movement between the body 12, on the one hand, and the slips 17 and packing sleeve 24, on the other hand.

Rotation of the ratchet collar 55 is prevented whenever a friction drag device 75 is connected thereto. This friction drag device includes a lower collar 76 slidable on the lower body section 12 and having a ring 77 attached thereto by means of screws 78. This ring 77 has the lower ends of circumferentially spaced, outwardly bowed springs 79 attached thereto, as by use of welding material 80, the upper ends of the springs being welded to an upper ring 81 secured to an upper collar 82, as by use of: the screws 83. This upper collar 82 is slidable along a lower skirt portion 84 of the ratchet collar 55, its upward movement along the ratchet collar being limited by engaging a transverse shoulder 85 thereon. Relative downward movement of the upper drag collar 82 along the skirt 84 is precluded by a coupling pin 86 threaded into the skirt and extending outwardly beyond its periphery for movement into a counterbore 87 in the upper drag collar. When shifted into this counterbore 87, the coupling pin 86 is cooperable with a lug or nger 88 that is secured to the upper collar 82 within its counterbore 87, as by means of welding material 89. The lower portion 90 of this coupling lug 88 is pointed, to preclude the pin 86 from abutting the lug 88, and thereby be prevented from moving into the counterbore 87. In addition, the lug is provided with an inner surface 91 that is inclined upwardly in the direction kin which the lower body 12 is rotated, for the purpose of releasing the split ratchet sleeve 65, or in a right-hand direction, to provide an inclined face tending to resist displacement of the coupling pin 86 out of engagement from the lug 88 when the pin 86 is moved in a longitudinal downward direction, as described hereinafter. During lowering of the apparatus, the coupling pin 86 occupies an initial po- Sition spaced a short distance below the lug 88, as seen most clearly in Fig. 2.

The apparatus is run in the well casing with the parts in the position depicted in Figs. l and 2. When in this position, the body 10 and ratchet sleeve 57 are in their uppermost position with respect ,to the other parts, thc safety sleeve 44 engaging the upper end or shoulder 92 of the counterbore 45, the seal rings 35, 39 being disposed off :their companion seats 34, 38, so as to open the ports 41. At this time, also, the packing sleeve 25 and slips 17 are in their retracted positions. The upper collar 82 of the friction drag device is engaging the shoulder 85 of the ratchet collar 55, the coupling pin 86 being out of engagement from the coupling lug 88, thereby yfreeing the ratchet collar 55 from any rotational restraint imposed by the frictional engagement of the outwardly bowed springs 79 with the Wall of the well casing B.

The app'aratusis lowered through the well casing with the parts in the position shown in Figs. 1 and 2, the split ratchet sleeve teeth 66 engaging the companion teeth 58 on the other member 57, topreclude relative downward movement of the body 10 with respect to the other parts. Durlng such downward movement, the tendency for any relative movement to occur between the body 10 and the ratchet collar 55, which might inadvertently release the split ratchet sleeve 65, is prevented, inasmuch as the drag device 75 is uncoupled rotationally from the ratchet collar 55, the body and the ratchet collar being free to move together arcuately.

When the location in the well casing B is reached at which the well packer A is to be anchored in packed-off condition, the tubular string C is elevated a slight distance, which elevating movement, acting through the threaded safety sleeve 44, upper valve head member 32, packing structure 24, tapered expander 19, slips 17, links 51, and slip ring 54 will effect elevation of the ratchet collar 55, for the purpose of moving the coupling pin 86 upwardly into the counterbore 87 of the upper drag collar 82, placing the pin 86 in circumferential alignment with the coupling lug 38. The tubular string C is then turned to the right, such motion being transmitted to the` packer body 19 and the ratchet sleeve 57 securedthereto.

`This turning motion also moves the key 63 arcuately,

causing it to expand the split ratchet sleeve 65 and open it to a larger diameter, in which its internal teeth 66 are moved out of engagement with the ratchet sleeve teeth 58. This relative turning movement can occur, since the coupling pin 86 will engage the inclined face 91 of the coupling lug or linger S8 on the upper collar 82, the drag springs 79 resisting or preventing turning of the ratchet collar 55. With the split ratchet sleeve 65 thus in its unclutched or uncoupied position, the tubular string C is then shifted in a downward direction, to correspondingly shift the body 1d in a downward direction.

The parts externally of the body 10 and the ratchet sleeve 57 secured thereto cannot move in a downward longitudinal direction, since such motion is resisted by the friction springs 7') of the drag device 75 engaging the wall of the well casing B. Accordingly, the body 1U moves downwardly freely, the key 63 not interfering with the downward movement in View of the longitudinal slot 62. in the ratchet sleeve. At first, the body 10 moves downwardly, to place the flange 37 within the counterbore 33 of the upper head member 32, and to bring its seals 35, 39 into sealing engagement with the companion seats 38, thereby closing the ports 41. Thereafter, the body l@ and vaive head member 32 move downwardly together, the packing sleeve and expander 19 also being urged in a downward direction, to shift the expander downwardly within the slips 17, which are then prevented from moving downwardly by the friction springs 79. In this manner, the tapered expander 19 is forced down into the slips 17, urging the latter in a radial outward direction into anchoring engagement with the wall of the well casing B. When such engagement occurs, the tapered expander 19 cannot move downwardly any further, which then allows the upper head member 32 to be moved toward the tapered expander, foreshortening the packing sleeve ZS and expanding it radially outward into firm r sealing engagement with the wall of the well casing, and also with the periphery of the body itl. The packing iaterial cannot move in an upward direction into the counterooro l5 of the head member 32, since the bridge ring 4S precludes this action from occurring.

During the downward movement of the parts, the coupling pin 86 on the ratchet collar skirt 84 is prevented from moving down out of engagement with the coupling lug 33 because of the inclined face 91 of the lug.

The pa 2er A is thus set in packed-off condition Within the well casing B, to bridge the annulus D between the body 16 of the tool and the well casing. The tool can then be used for any desired purpose. If it is desired to swab the well, then the swabbing of the tubular string C will produce a differential hydrostatic head in the annulus D between the tubular string and the casing. However, this head of fluid cannot displace the well packer A from its set condition because of the expanded packing sleeve 25, and of the slips 17, which are anchored against the casing B and resist downward movement of the tool therewithin. Whenever it is desired to equalize the hydrostatic head, it is merely necessary to move the tubular string C upwardly, for the purpose of pulling the flange 37 out of its companion seat 38 in the upper valve head member 32, thereby exposing the ports 41. After the hydrostatichead has been equalized, the tubular string C can again be moved downwardly, after rst having partially turned the tubing string C and the packer body 10 to the right, for the purpose of disconnecting the ratchet sleeve 57 from the split ratchet ring 65. Such upward and downward movement can occur as often as desired, without releasing the packing sleeve 25 and the slips 17 from the well casing B.

In the event it is desired to retrieve the well packer A from the well bore, it is merely necessary to move the tubular string C and the body 10 in an upward direction, the ratchet sleeve 57 ratcheting freely through the ratchet ring 65. When the safety sleeve ring 44 engages the shoulder 92 of the counterbore 45, it will transfer the upward movement of the body 10 to the upper head member 32, and this action will pull the head member away from the expander 19, allowing the packing sleeve 25' to retract. When fully retracted, the packing sleeve will then pull on the upper expander 19, in order to urge it in `an upward direction away from the slips 17, and thereby retract the latter from the well casing B, in view of the tongue and groove connection 22, 23 therebetween. During this time, the drag springs 79 are tending to prevent upward rnovement of the slips 17. Following the retraction of the slips 17, the tubular string C is elevated,

to elevate the entire well packer A within and from the well casing, the friction drag springs 79 frictionally riding along the wall of the well casing.

As the tubing string C is elevated and withdrawn from the well casing, its joints are disconnected at the top of the well bore above the usual rotary table (not shown). It is desired to effect a disconnection between the joints of tubing above the rotary table and those within the well bore by rotating the table, in the interests of speed and the savings of time. However, it is not desired to rotate the drag springs '79 around the wall of the well casing B, which they frictionally engage, since they may be damaged or destroyed. In the present instance, the drag device 75 is automatically disconnected from the remainder of the well packer whenever the tubing string C is lowered, for the purpose of supporting it in the rotary table, as is customary. The parts are usually lowered to a substantial extent in a rotary table prior to disconnection of a joint, and such lowering movement will be transmitted through the split ratchet ring to the ratchet collar 55, to lower the coupling pin 86 out of its coupling position with respect to the lug 88 of the upper drag collar 55. Accordingly, the rotation of the rotary table rotates the tubular string C and all of the packer parts, including the ratchet collar 55, within the upper drag collar 82, without rotating the latter and its drag springs 79 around the wall of the well casing. Of course, when the tubular string C is again elevated in the well casing, the coupling pin 86 will again be placed in coupling relation to the drag collar lug 88, but, upon relowering of the tubular string when it is again to be supported by the slips (not shown) in the rotary table, the coupling pin 86 will again be moved out of its coupling relation to the lug 8S.

The entire apparatus can be rotated in the well bore whenever it is to be removed therefrom, to enable rapid disconnection of the joints of tubing at the vtop of the hole, and such rotation occurs without rotating the drag device around the well casing B.

If, for some reason, the packing sleeve 25 and the slips 17 cannot be retracted, for the purpose of removing the well packer from the wellv casing, the threaded safety joints 42, 43 and 59, 60 enable the tubing string C and the body 10, and any tubing depending from the body, to be removed. Thus, in the event the slips 17 are stuck in the hole and cannot be freed, the tubular string C is rotated to the right. Since the parts externally of the packer body 10 cannot rotate, being anchored to the well casing B, such rotation effects a shearing of the shear screw 61 connecting the ratchet sleeve 57 to the lower body section 12. Rotation ofthe body 10 then produces a disconnection of the lower body section 12 from the ratchet sleeve 57 at their left-hand threaded interconnection 59, 60. This same rotation of the body effects a disconnection of the upper body section 11 from the threaded sleeve 42, which is prevented from rotating by means of its key connection 46, 47 to the valve head member 32, that is precluded from turning, since the parts connected thereto are anchored to the well casing B. The taking of a suicient number of turns on the tubular string C and the body 10 will effect complete unthreading of both external lefthand threads 42, 60 on the body from the corresponding internal left- hand threads 43, 59 on the threaded safety sleeve 44 and the ratchet sleeve 57, freeing the body 10 from the remainder of the well packer and enabling it to be elevated and withdrawn through the packer parts. Any tubing connected below the body can also be withdrawn from the packer parts. Such withdrawing action is not interfered with by the ratchet key 63, since the latter only extends into the slot 63 in the sleeve 57, the latter remaining in the well casing.

The inventors claim:

l. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a releasable lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body; said lock device including an annular member on said body, means connected to said normally retracted expansible means and releasably connected longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a releasable lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body; said lock device including an annular member on said body, and means connected to said normally retracted expansible means and releasably connected to said annular member; and a left-hand threaded connection between said body and annular member to enable said body to be rotated and disconnected from said annular member for withdrawal to the top of the well casing.

3. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a releasable lock device operatively connected to said body andl normally retracted expansible means for selectively preventing or permitting such longitudinal movement of thebody, said lock device including a coupling member connected to said normally retracted expansible means and adapted tok be held against substantial rotation, a

sleeve surrounding said body, and releasable ratchet s meansV releasably connecting said sleeve and coupling member;.and means releasably connecting said body toV saidA sleeve-to enable said body to be disconnected from said-sleeve andwithdrawn to the top-of the wellca'sin'g. 4'. In al welltool a body connectible toa tubular string v'for lowering in a well casing; normally retracted expansible means on Vsaid body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a releasable lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body, said lock device including a coupling member connected to said normally retracted expansible means and adapted to be held against substantial rotation, a sleeve surrounding said body and having external ratchet teeth thereon, an expansible and contractible ring carried by said coupling member and having internal ratchet teeth engageable with said external teeth to couple said ring and sleeve together against longitudinal movement in one direction, means on said sleeve and coupling member engageable with said ring to expand said ring out of engagement from said external ratchet teeth in response to rotation of said body and sleeve; and means releasably connecting said body to said sleeve to enablesaid body to be disconnected from said sleeve and withdrawn to the top of the well casing.

5. In a well tool: a body connectible to a tubular string for lowering in a Well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a releasable lock device operatively connected to said body and normally retracted expansible means for selectively preventing and permitting such longitudinal movement of the body, said lock device including a coupling member connected to said normally retracted expansible means and adapted to be held against substantial rotation, a sleeve surrounding said body and having external ratchet teeth thereon, an expansible and contractible ring carried by said coupling member and having internal ratchet teeth engageable with said external teeth to couple said ring and sleeve together against longitudinal movement in one direction, means yon said sleeve and coupling member engageable with said ring to expand said ring out of engagement from said external ratchet teeth in response to rotation of said body and sleeve; and a lefthand threaded connection between said body and sleeve to enable said body to be rotated and disconnected from said sleeve for withdrawal to the top of the Well casing.

6. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a releasable lock device operatively connected to said body and normally retracted expansible means for selectively preventing and permitting such longitudinal movement of the body, said lock device including a coupling member connected to said normally retracted expandable means and adapted to be held against substantial rotation, a sleeve surrounding said body and having external ratchet teeth thereon, an expansible and contractible split ring carried by said coupling member and having internal ratchet teeth engageable with said external teeth to couple said ring and sleeve together against longitudinal movement in one direction, means on said coupling member engaging said ring at one side of its split portion, means slidable in a longitudinal slot in said sleeve and engageable with said ring at the other side of its split portion to expand said ring out of engagement from said external ratchet teethin response to rotation of said body and sleeve; and means releasably connecting said body to said sleeve to enable said body to be disconnected from said sleeve and withdrawn to the top of the well casing.

7. In-a well tool: a bo'dy connectibleA to a tubular 9 string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a

, releasable lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body; a drag device engageable with the well casmg; and coupling means releasably connecting said drag device to said lock device, said coupling means being releasable upon downward movement of said lock device relative to said drag device to permit rotation of said lock device with respect to said drag device.

8. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body expandible outwardly into engagement with the well casing in response to downward movement of the body with respect to said normally retracted expansible means; a releasable lock dcvice operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such downward movement of the body; a drag device engageable with the well casing; and coupling means releasably connecting said drag device to said lock device; said coupling means including a coupling element on said lock device adapted to be coupled to said drag device and movable downwardly with said lock device out of coupling relation to said drag device upon downward movement of said body to enable said lock device to be rotated with respect to said drag device.

9. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted exansible means; a releasable lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body, said lock device including a coupling member connected to said normally retracted expansible means, a sleeve surrounding said body and having external ratchet teeth thereon, an expansible and contractible ring carried by said coupling member and having internal ratchet teeth engageable with said external teeth to couple said ring and sleeve together against longitudinal movement in one direction, means on said sleeve and coupling member engageable with said ring to expand said ring out of engagement from said external ratchet teeth in response to rotation of said body and sleeve; means releasably connecting said body to said sleeve to enable said body to be disconnected from said sleeve and withdrawn to the top of the well casing; a drag device engageable with the well casing; and coupling means releasably connecting said drag device to said coupling member, said coupling means being releasable upon longitudinal movement of said coupling member relative to said drag device to permit rotation of said coupling member with respect to said drag device.

10. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body; means on said body engageable 4with said normally retracted expansible means for retracting said normally retracted expansible means from its outwardly expanded position;

10 said retracting means being releasably connected to said body to enable said body to be disconnected from said retracting means and withdrawn to the top of the well casing.

ll. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body; means on said body engageable with said normally retracted expansible means for retracting said normally retracted expansible means from its outwardly expanded position; said retracting means including a left-hand threaded connection with said body to enable said body to be rotated and disconnected from said retracting means and Withdrawn to the top of the well casing.

12. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body; said lock device including an annular member on said body, means connected to said normally retracted expansible means and releasably connected to said annular member, and means releasably connecting said body to said annular member to enable said body to be disconnected from said annular member and withdrawn to the top of the well casing; means on said body releasably connected to said body and engageable with said normally retracted expansible means for retracting said normally retracted expansible means from its outwardly expanded position and for enabling said body to be disconnected from said retracting means and withdrawn to the top of the well casing.

13. In a well tool: a body connectible to a tubular string for lowering in a well casing; normally retracted expansible means on said body and expandible outwardly into engagement with the well casing in response to longitudinal movement of the body in one direction with respect to said normally retracted expansible means; a lock device operatively connected to said body and normally retracted expansible means for selectively preventing or permitting such longitudinal movement of the body; said lock device including an annular member on said body, and means connected to said normally retracted expansible means and releasably connected to said annular member; means on said body engageable with said normally retracted expansible means forretracting said normally retracted expansible means from its outwardly expanded position; a left-hand threaded connection between said body and annular member; said retracting y means including a left-hand threaded connection with said body; both of said left-hand threaded connections enabling said body to be rotated and disconnected from said annular member and retracting means for withdrawal of said body to the top of the well casing.

References Cited in the tile of this patent UNITED STATES PATENTS 1,525,368 Cameron Feb. 3, 1925 2,368,401 Baker Jan. 30, 1945 2,429,910 Anderson et al. Oct. 28, 1947 2,618,342 Meyer Nov. 18, 1952 2,633,917 Baker et al. Apr. 7, 1953

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