US2917114A - Well packer and releasable latch for hook wall means - Google Patents

Description

Dec. 15, 1959 A. E, LEVENDOSKI WELL PACKER AND RELEASABLE LATCH FOR HOOK WALL MEANS 2 Sheets-Sheet 1 Filed May 21, 1957 A fro/m5 r A. E. LEVENDOSKI 2,917,114

WELL PACKER AND RELEASABLE LATCH FOR HOOK WALL mans Filed may 21.

Dec. 15, 1959 2 Sheetg-Sh'eet 2 INVENTOR.

A woe/m United States Patent WELL PACKER AND RELEASABLE LATCH FOR HOOK WALL MEAN S Alfred E. Levendoski, Depew, N.Y., assignor to American Iron & Machine Works Company, Inc., Oklahoma City, Okla., a corporation of Delaware Application May 21, 1957, Serial No.'660,611 4 Claims. (Cl. 166- 139) This invention pertains to a releasable latching de vice, and more particularly to such a devicefor 'releasably holding in unset position the slips of a hookwall means used to holdan apparatus, especially a well packer, in position in a well, and to a well packer embodying such a device.

An object of the invention is to providesuch a device which is quick and certain in itsoperation, both in movement to and from latched position andwhile in latched out motion relative to the mandrel axis and are spring biased inwardly, the threads of both mandrel and nut being of buttress form wherebyrelative axial movement of the mandrel and nut is possible in one direction with the nut ratcheting overthe thread but is prevented in the other direction except upon relative rotation to unscrew the nut from the mandrel. Similar devices have been used previously to lock packers and their hookwall means in unset position, but the subject invention has the advantages of faster, surer operation coupled with'economy of manufacture.

For a description of a preferred embodiment of the invention reference will be made to the accompanying drawing wherein:

Figure 1 is an elevation, partly in section, showing a well packer embodying the invention, the latching device thereof being in the unlocked or free position and the packer sleeve and hookwall means thereof beingset;

Figure 2 is a view similar to Figure 1 showing the latching device in the'locked or active position, both the packer sleeve and its hookwall'means being. unset;

Figure 3 is a view partly in elevation and partly in section, drawn to a larger scale than Figures 1 and 2, showing the latching device used in the well packer of Figures 1 and 2;

Figure 4' is a top view of the latching device shown in Figure 3, being a section on line 4-4 of Figure 3, and

Figure 5 is a section on line 55 of Figure 3.

Referring'now to both Figures 1 and 2, there is shown a well packer disposed in the casing 10 of a well. The well packer comprises a latching mandrel including a tube 11 upset at its lower end at 12 (see'Figure 2) to provide a threaded pin 13. The latching mandrel further includes a sleeve 14 which is slipped over the other end of the tube and'welded to the tube at 15. The sleeve thereof. The upper end of mandrel 22 (see Figure 2) is provided interiorly with a threaded socket 23' for connection to a string of tubing or the like and is exteriorly grooved at 24 to facilitate engagement of the apparatus with anovershot in case it has to be fished out of the well.

Slidably disposed on tube 11 below packer expander cone 23 is a slip expander cone 30 to the upper end of which, as shown in Figure l, is fastened a packer sleeve 31 made of oil resistant rubber-like material. As shown in Figure 1 the packer sleeve has been expanded by entrance therein of the packer expander cone 23, the packer sleeve being expanded into sealing engagement with thecasing. In'the Figure 2 position the packer expander cone 23 is withdrawn from the packer sleeve; Even in the Figure 1 position the packer expander cone does not enter the packer sleeve far enough for flange 32 at the upper end of the cone 23 to contact cuif ring 33 at the upper end of the packer sleeve. Flange 32 and cuff ring 33 are useful in protecting the packer sleeve when it is being raised in the well casing, especially through'collars. The motion of the expander cone 23 into the packer sleeve is limited by its lower end contacting clamp ring 34 at the lower end of the packer sleeve, and in this position the internal diameter of cuff ring 33 is at least as large as that of the adjacent part of the expander cone 23.

Secured to tube 11 above threaded sleeve 14- are a plurality of stops 40 azimuthally spaced around the tube. As shown in Figure 2, these stops are engageable with a drive ring 41 which'is connected to the lower end of sleeve 42 extending down from the lower end of slip expander cone 3%). Stops 40 thus limit relative motion in one direction of the tube 11 and the packer sleeve assembly comprising the packer sleeve and slip expander cone.

' A plurality of hookwall slips 45 are connected to the slip expander cone by dovetail tongues 46 extending out from flatsides of the cone into dovetail grooves 47 on the flat inner walls of the slips. The slips are also con nected by double pivoted links 48 to slip ring 49 which "is Slidably-mounted on sleeve 42. A plurality of easing engaging bow springs are connected 'at their upper ends "to the slip ring 49* and at their lower ends to the outer portion of a latching device 60, the inner portion of which includes the threaded sleeve 14 with which it is in engagement in Figure 2. Engagement ofslip ring-49 with drive ring- 41, as is also shown in Figure 2, limits downward motion relative to the packer assembly of the slip assembly comprising the slips, links, slip ring, and

bow springs.

In the Figure 2 position the slip assembly is held by the latching device against axial movement relative to the tube. The packer sleeve assembly isheld against such axial movement by engagement of its drive ring 41 between stops id and slip ring 49. In this position the slips are in their retracted position and the packer sleeve is in its relaxed or unexpanded condition, and since the parts areheld against relative axial movement in either direction the packer can be lowered or raised in the well without the packer sleeve or hookwall slips setting.

As will be explained hereinafter, the latching device 60 can be freed by rotation of the tube 11, the bow springs of the slip assembly holding the outer or nut portion of the device stationary whilethe inner threaded portion 14 is unscrewed therefrom. Thereafter downward motion of the tube does not cause the slip assembly to move downwardly, the latter being held stationary by the bow springs-frictionally engaging the casing. At this point the packer sleeve assembly, comprising the packer sleeve and slip expander cone, lies between the downwardlyrmoving packer expander cone thereabove and the stationary slips therebelow. The packer sleeve assembly first moves down with the packer expander cone to cause the slip expander cone to move the slips radially out- Wardly into gripping engagement with the well casingx Then, after the slips are thus set, further downward mo: tion of the packer expander cone expands the packer sleeve radially outwardly into sealing engagement with the casing. This is the Figure 1 position.

When it is desired to remove the well packer from the well, or position it at a diflerent level therein, the tubing string is lifted to withdraw the packer expander cone from the packer sleeve. Further upward motion of the tubing string causes stops 40 to engage drive ring 41 and lift the packer sleeve assembly. Upward motion of the packer sleeve assembly causes the slip expander cone to be withdrawn from the slips and to retract them, the slips being held against upward movement by the bow springs. Finally, drive ring 41 of the packer sleeve assembly engages slip ring 49 of the slip assembly and the slip assembly too moves upwardly. At the same time the nut of the latching device ratchets axially over the threaded sleeve 14, as will be next explained, and the packer is again inthe Figure 1 position ready to be moved to the desired new location.

Referring now particularly to Figures 35, there are shown the details of the latching device 60. As previously stated this device is of the type comprising a threaded mandrel and a segmental nut. The threaded mandrel comprises tube 11 and sleeve 14 welded thereto at 15. This portion of the latching device therefore moves with tube 11. The nut of the latching device, as previously stated, is connected to the bow springs of the slip assembly and therefore moves with the slips. In the immediately following portion of the description the two parts of the latching device, the threaded mandrel and the nut, will sometimes be referred to as the tube portion and the slip portion to emphasize their relationship to the rest of the well packer.

The nut or slip portion of the latching device, that is,

the portion moving with the slips, includes an annular housing comprising a thick sleeve 61 and a cap 62. The minimum inner diameter of the sleeve is larger than the outer diameter of the upset 12 on the tube and slightly larger than the crest diameter of the threads 16 so that it can be assembled by slipping it over the upset end of the tube 11. It could not be put on from the other end because of interference by stops 40 welded onto the tube. The cap 62, on the other hand, has a minimum inner diameter that is too small to pass over threads 16 so that it must be placed on the tube from the other end and is provided with notches 63 to pass over the stops. The cap is fastened to the sleeve by means of screws 64.

The exterior of the sleeve 61 and cap 62 are shaped to provide channels 70 to allow drilling mud or other well fluid to pass by the housing. The exterior of the sleeve is also provided with recesses 71 and the cap is cut back at 71' to receive the lower ends of springs 50 which are secured therein by screws 72.

Interiorly the sleeve 61 is provided with slots 73 of rectangular cross section whose bottoms or outermost walls 74 are inclined, flaring upwardly from the tube axis. In each of the several slots 73 is slidably disposed a pawl 75 having a body of generally rectangular cross section correlative to the slot section. The outermost or back sides 76 of the pawls taper toward the bottoms of the pawls correlative to the inclination of the flaring back walls of the slots. The faces or innermost sides of the pawls are provided with thread segments 77 correlative to threads 16. The pawls are limited in their downward travel, when not engaged with threads 16, by the lower end 78 of the sleeve 61. The cutting of slots 73 so as to leave end 78 intact is facilitated by first cutting annular groove 79 in the sleeve.

The pawls are guided at their sides by the sides of the slots and are additionally guided and prevented from falling radially inwardly out of the slots by means of guide rods 80. The guide rods pass through holes 81 in the pawls. The guide rods are angularly disposed relative to the tube axis and are parallel to the back walls of the slots. The guide rods are held in position by being soldered into cap 62 at their upper ends. Helical compression springs 82 concentric with guide rods urge or bias the pawls downwardly and inwardly. The upper ends of the springs bear against cap 62 and the lower ends are received in recesses 83 in the pawls.

The spring mounted pawls may be said to constitute a segmented nut engageable with the threaded mandrel constituted by tube 11 and threaded sleeve 14.

In operation, when the nut or slip portion of the latching device moves down relative to the threaded mandrel or tube portion of the latching device, its threaded segments ratchet over the thread 16, the segments or pawls moving up and out against the pressure of springs 82 while the threads 77 pass over threads 16. Then the springs push the pawls down and in to engage the threads 77 beneath threads 16. Motion of the nut in the opposite direction is then prevented by the fact that the engaged flanks 90, 91 of the mandrel thread and nut thread, respectively, are of such angle to the tube axis, e.g. perpendicular thereto, that axial pressure between the thread flanks does not create any force component tending to move the pawls radially outwardly, or if such force component is created it is insufiicient to overcome the sliding friction between the thread faces and the pressure of springs 82. The latching device can then be separated only by unscrewing the nut from the mandrel. Such separation is therefore not eifected by the axial motion of the well packer required to lower it or raise it to the desired level. However when such separation is desired it can be accomplished quickly by virtue of the triple thread which reduces the number of turns required to release the latching device.

By virtue of the guide channels 73, the pawls are prevented from turning out of position such that their threads would be crossed relative to the threads 16 which would prevent reengagement of the latching device. This is a very important feature for the device must operate satisfactorily at the end of a string of pipe which may extend several thousand feet down into the ground in the presence of a mixture of many fluids and assorted solids. Failure to operate would mean that the pipe would have to be withdrawn from the well, an operation taking many hours or even a whole day and costing considerable money.

By virtue of the guide rods the pawls are retained in the guide c'hannels'and are additionally guided to prevent their becoming cocked and wedged in the channels which might keep them from returning to their innermost position under spring pressure.

Viewed in another light, the pawls may be said to be guided along the axis of the guide rods in the in and out motion of the pawls and the pawls are prevented from rotating on the guide rods by engagement of the sides of the pawls with the guide channels. However viewed, the guide channels cooperate with the guide rods to provide a reliable control of the motion of the pawls. I While a preferred embodiment of the invention has been shown and described, many modifications thereof can be made by one skilled in the art without departing from the spirit of the invention and it is desired to protect by Letters Patent all forms of the invention falling within the scope of the following claims.

I claim:

1. A well packer comprising a tube upset at its lower end and exteriorly threaded at said end, a sleeve having a smaller inner diameter than the outer diameter of the upset end of said tube and disposed around the tube and fastened to the tube near its lower end, said sleeve having a buttress type thread thereon with its steep flank on the lower side, a plurality of azimuthally spaced t ps eemed to said tube above said sleeve and spaced,

therefrom, means cooperable with said threaded sleeve to act as a releasable latch including a housing formed of a sleeve and a cap, said housing sleeve having a minimum inner diameter larger than the outer diameter of said upset end of the tube and larger than the outer diameter of said threaded sleeve, said cap having a minimum inner diameter smaller than the outer diameter of said threaded sleeve but larger than the outer diameter of the tube at its upper end, said cap having notches therein azimuthally spaced apart correlative to the spacing of said stops and larger than said stops, said cap being fastened to the upper end of said housing sleeve, spring biased pawl means in said housing for engaging said threaded sleeve after ratcheting axially down over the threaded sleeve to prevent upward movement of the housing relative to the threaded sleeve except when accompanied by relative rotation thereof, a packer sleeve assembly including a packer sleeve and a downwardly converging slip expander connected to the bottom of the packer sleeve, said packer sleeve assembly being slidably mounted on said tube above said stops, a packer expander means connected to said tube at the upper end thereof, means connected to said packer expander means for connection with a well pipe, a slip assembly connected to said housing and including a plurality of slips slidably dovetailed to said slip expander and including further means to frictionally engage with a well casing to tend to prevent motion of said slips relative to such casing, and means limiting downward movement of said slip assembly relative to said packer assembly, the distances between said packer expander means and said stops and said threaded sleeve being such that when said pawls in said housing are engaged with said threaded sleeve said packer sleeve assembly is engaged with said stops and said slip assembly is in its lowermost position relative to said slip expander drawing said slips away from casing engaging position and said packer expander means is withdrawn relative to said packer sleeve which is relaxed.

2. The combination of claim 1 in which the spring biased pawl means in the housing comprises a plurality of pawls having thread segments on their inner faces correlative to those on the threaded sleeve, the backs of the pawls being tapered downwardly, the housing sleeve has slots therein correlative to the shape of the pawls, guide rods secured to the cap and disposed one in each slot parallel to the back wall thereof pass through holes in the pawls parallel to the back faces of the pawls, and helical compression springs disposed one concentric with each guide rod bear against the cap at their upper ends and are received in recesses in the tops of the pawls.

3. A latching device comprising an exteriorly threaded mandrel and a segmental nut engageable therewith, said nut including a housing having a plurality of slots therein, a pawl member received in each slot and having means on its inner face for engaging said threaded mandrel to prevent relative axial movement therebetween in one direction except when the nut is rotated, a guide rod in each slot passing through the pawl member, and means biasing each pawl toward said threaded member.

4. The combination of claim 3 in which said housing comprises a sleeve, said slots in the housing extending from the top of the sleeve part way to the bottom thereof, and a cap connected to the top of said sleeve closing said slots, said guide rods being secured to said cap, said biasing means including a helical compression spring around each guide rod hearing at its upper end against the cap and at its lower end against the pawl member in the corresponding slot.

References Cited in the file of this patent UNITED STATES PATENTS 1,098,265 James May 26, 1914 1,593,909 Nixon July 27, 1926 2,205,748 Knox June 25, 1940 2,352,423 Church June 27, 1944 2,632,514 Fitzpatrick Mar. 24, 1953 2,769,499 McKissick Nov. 6, 1956

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