US2737247A

US2737247A - Well packer apparatus

Info

Publication number: US2737247A
Application number: US368638A
Authority: US
Inventors: Reuben C Baker; Austin Benjamin Lewis
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1950-09-26
Filing date: 1953-07-17
Publication date: 1956-03-06
Anticipated expiration: 1973-03-06

Description

March 6, 1956 R. c. BAKER ETAL WELL PACKER APPARATUS Original Filed Sept. 26,, 1950 2 Sheets-Sheet 2 v p a I VI UW d 4/ M J ll'll'l Ill I'lllllllllllllllllll INVENTORS. REUBEN C. BAKER, BENJAMIN LEW/s AUSTIN, y

7% pr razweYS United States' Patent WELL PACKER APPARATUS Reuben C. Baker, Coalinga, and Benjamin Lewis Austin, Dowuey, Califi, assignors to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of California Original application September 26, 1950, Serial No. 186,856, now Patent No. 2,707,998, dated May 10, 1955. Divided and this application July 17, 1953, Serial No. 368,638

13 Claims. (Cl. 166-218) The present invention relates to subsurface well apparatus, and more particularly to well packer apparatus set in well bores, and to the placing of strings of tubing in fluid tight communication with such packers.

This application is a division of our application for Setting Tool, Dump Bailer and Well Packer Apparatus, Serial No. 186,856, filed September 26, 1950, now Patent No. 2,707,998.

An object of the invention is to provide well packer apparatus capable of being set in a well bore and of having a guide attached subsequently to its upper portion.

Another object of the invention is to provide apparatus for attaching'a guide to the upper portion of a well packer disposed in a well bore.

A further object of the invention is to provide apparatus capable of attaching a guide to the upper end of a well packer, and of placing a tubular string in a sealing relation to the well packer, in order to establish leakproof communication between the packer and the tubing string. The guide may be permanently latched to the set packer to facilitate running of the tubing string and its sealing devices into and out of the packer.

Yet a further object of the invention is to provide an arrangement for lowering a guide on a running-in string, latching the guide to a well tool, and releasing the running-in string from the latched guide.

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 invention; but it is 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:

Figures 1 and 1a together constitute a longitudinal section, partly in side elevation, of well apparatus disposed in a well bore, Fig. 1a constituting a lower continuation of Fig. 1;

Fig. 2 is a cross-section, on an enlarged scale, taken along the line 2-2 on Fig. 1;

Fig. 3 is a view similar to Fig. 2, illustrating the coupling or snap ring in released position;

Fig. 4 is a fragmentary longitudinal section, on a greatly enlarged scale, illustrating the adapter or guide shown in Fig. l in latched relation to the upper end of the packer body and the tubing string still coupled to the guide;

Fig. 5 is a view similar to Fig. 4, illustrating the tubing string released from the guide;

Fig. 6 is view similar to Fig. 1, of the guide attached to the packer body, and with the tubing string in sealed relation to the packer body.

In general, the apparatus disclosed in the drawings includes a well packer which has been set in an open well bore B through use of suitable apparatus (not shown),

but which is fully described in our above-identified parent application. The packer A has been set in the well bore, and cementitious material E dumped around it; so as to leave an unobstructed passage through it.

After the packer A has been set, the cementitious material E deposited around it, and setting equipment (not shown) removed from the well bore, a. tubular string G may be lowered in the bore hole for the purpose of coupling a guide H to the upper end of the well packer. The tubing string is also placed in sealing engagement with the interior of the well packer. Coupling of the guide H to the packer A, and the placing of the tubular string G in sealed relation to the well packer, preferably occurs during the same trip of the tubing string into the well bore, in order to save time with its attendant economies of operation. The guide itself remains coupled to the well packer, to guide the lower end of a tubing string, or the like, back into appropriate relation to the well packer, or to facilitate the running of any other equipment into or through the set packer.

The well packer portion A of the apparatus includes a tubular body 10 having a guide or lower abutment 11 threaded on its lower end. An upper abutment 12 is slidable in a relative downward direction along the packer body a substantial distance above the lower abutment 11, and is engageable with a set of upper segmental slips 13 disposed around the body immediately below the abutment 12. Although the well packer A is shown set in the 7 well bore B, it is initially lowered in the well bore with its parts occupying an initial position, and with some of the parts retracted to avoid engagement with the wall of the well bore. The abutment 12 is held initially in an upper position by a shear pin 12a attaching it to the body 10. These slips 13 are held initially in retracted position by shear screws 14 attaching them to an upper conical expander 15 initially secured to the body 10 by one or more shear pins 16. The converging inner surfaces 17 of the upper set of slips and the companion outer surface 18 of the expander 15 are so disposed with respect to one another as to secure the packer against movement in an upward direction within the well bore B, following outward expansion of the slips 13 into engagement with the wall of the bore hole.

A set of lower segmental slips 19 is provided adjacent the lower abutment 11, these slips being secured'by shear screws 20 to a lower tapered expander 21 attached initially to the body 10 by one or more shear pins 22. The direction of taper on the exterior 23 of the lower expander and the taper on the inner surfaces 24 of the lower slips are such as to hold the well packer against movement in a downward direction, following expansion of the slips 19 outwardly against the wall of the well bore B.

A suitable lock is provided between the upper abutment and the body 10, to permit upward movement of the body within this abutment, but to preclude its downward movement. As illustrated, the lock includes a split ring or sleeve 25 contained within the upper abutment 12 and having an inner roughened surface 26 for engaging the periphery of the packer body 10. The outer surface of the latch sleeve is provided with tapered surfaces or teeth 27 engaging correspondingly tapered surfaces 28 in the upper abutment. These surfaces are inclined in an upward and outward direction, functioning as cams Wedging the latch sleeve 25 between the body 10 and the upper abutment 12, in the event the body tends to move relatively downward within the abutment. However, upward movement of the body 10 tends to move the latch sleeve 25 upwardly in the upper abutment 12 and relieves the coengaging cam faces 27, 28,

which allows the ring 25 to expand and become free. of the body 10. In effect, the latch arrangement con- -39 stitutes a one-way coupling or clutch permitting relative upward movement of the body within the upper abutment 12, but precluding its relative downward movement therewithin.

A suitable packing 29, such as a packing sleeve of rubber or similar pliant, elastic material, is disposed around the body 10 between the upper and

lower expanders

15, 21. This packing sleeve encompasses a cylindrical stop sleeve 39 mounted on the packer body 10, and having a length which is substantially less than the initial distance between the expanders f5, 21 when the

shear pins

16, 22 are intact. This stop sleeve 3% serves to limit the extent of outward expansion of the packing sleeve 29, upon foreshortening of the latter as a result of moving the

expanders

15, 21 toward one another.

In setting the packer, a downward force is exerted on the upper abutment 12 of suflicient extent to shear the pin 12a and the screws 14 attaching the upper slips 13 to the upper expander 15. These slips are then moved downwardly along the upper expander 15 and radially outward into anchoring engagement with the well bore B. Such outward expansion of the upper slips 13 can occur, since their retaining shear screws 14 have a lesser combined shear value than the pins 16 securing the upper expander 15 to the body 10. These last-mentioned pins have a lesser value than the pins 22 holding the lower expander21 to the body 10, and the screws 20 holding the lower slips 19 to the lower expander.

After the upper slips 13 have been engaged with the wall of the well bore B, an upward strain or pull is imparted to the packer body 10, which shears the pins 16 holding the upper expander 15 to the body 16 and moves the lower expander 21 and lower slips 1) with the body toward the upper expander. This action foreshortens the packing sleeve 29 and effects its outward expansion into firm sealing engagement with the wall of the well bore B. The packing sleeve cannot be foreshortened and expanded laterally outward beyond the extent at which the'stop sleeve 30 engages both the upper and

lower expanders

15, 21, thereby preventing outward expansion of the packing sleeve to too great a degree, which might result in its inability to effect a proper seal with the well bore B.

An increase in the upward pull or force on the packer body 10 substantially simultaneously shears the pins 22 holding the lower expander 21 to the body 10 and the screws 20 attaching the lower slips 19 to the lower expander, causing the lower body abutment 11 to shift the lower slips 19 upwardly along the lower expander 21 and radially outward into anchoring engagement with the wall of the bore hole B (Fig. la). The latch sleeve 25 then is wedged by the lowering tendency of the body 10 between the body and the upper abutment 12, to lock the body 10 against downward movement. Any tendency for the body to move downwardly is transmitted through the upper abutment 12 and upper slips 13 to the formation wall. If such slips do not remain wedged against the formation wall, then the downward moving tendency is transmitted through the upper expander 15, packing 29 and stop sleeves 30, lower expander 21 and lower slips 19 to the formation wall. It is to be noted that the wickers 10:: on the lower slips are relatively deep, so as to embed themselves to a substantial extent in the wall of the well bore B.

Any tendency of the body 10 to move upwardly is resisted by engagement of the lower abutment 11 with the lower slips 19, the upward force being transmitted from the latter through the lower expander 21, packing and stop sleeves 29, 30, upper expander 15 and upper slips 13 to the formation wall. Here again, the wickers 01' teeth 13a on the upper slips face in an upward directron and are relatively deep, to embed themselves quite extensively in the formation wall.

In the manner just described, thev well packer A is anchored in packed-elf condition against longitudinal movement in both directions within the open well bore B.

The specific well packer illustrated is designed to be set in open holes. It is desired to have an open passage 32 through it, to allow equipment to be lowered into or through the packer body 10. In order to supplement the anchoring action of the

slips

13, 19, the packer body It) preferably has an upper extension which may include one or more tubular body portions 10:: secured to the lowermost body portion 10, and to each other, by suitable threaded couplings 1011. The

body portions

10, 10a preferably have substantially the same internal and external diameters. They may extend upwardly from the well packer to as great an extent as desired. As an example, the tubular body 10 and its extensions 10a may project about four to ten feet above the upper packer abutment 12.

As is evident from an inspection of Figs. 1 and la, the well packer A is anchored firmly in the open Well bore B in leakproof relation with respect thereto. This anchoring and sealing relation is enhanced by the cementitious material E that has been dumped upon the upper abutment 12, upper slips 13, upper expander 15 and packing sleeve 29, and also around the packer body ill), 16a and its couplings 10b. Upon setting and hardening, the cementitious material forms a supplemental plug or packer anchoring the

packer body

10, 10a in the open well bore B. Not only does the cement plug E prevent leakage between

body

10, 10a and the wall of the Well bore B, but the body is itself embedded in the cement, the holding force of the cement being enhanced by engaging the upper and lower ends of the threaded coupling collars 10b. The cementitious material is usually sufficient in quantity to provide an annulus of cement around the

packer body

10, 10a extending up to the upper portion of the latter, but not surrounding the uppermost portion.

In order to facilitate the centering of the well packer A in the well bore B, centering wings or ribs )5 may be provided on the packer body extensions Mia. In view of the length of'the body 10, we, the centering wings or ribs will preclude any substantial inclination or tilting of the well packer A and its body elements It Na in the well bore, particularly in crooked holes. The resultant coaxiality of the body 10, 16a will also result in the deposit of a substantially uniform annulus of cementitious material E around the body, which not only will provide a proper cement seal between the body and wall of the formation, but will insure the permanent coaxial position of the body in the well bore, regardless of harmful effects that might occur on the slips and packing sleeve in the future. The coaxiality of the packer body 10, Mia will also facilitate the subsequent coaction or correlation of other subsurface well equipment with the well packer A.

After the packer A has been set in the well bore and the cementitio'us material E deposited around it, the entire setting mechanism (not shown), is removed from the well bore, which leaves the well packer and the cement in the condition illustrated in Figs. 1 and 1a, in which the passage 32 through the packer is fully open. After the cement E has set and hardened, a string of tubing G is to be disposed in sealing relation to the well packer, to allow well production below the packet to enter the packer and pass upwardly through the tubing string to the top of the well bore. Conversely, fluids may be pumped down the tubing string G and through the packer A into the well bore B below the packer.

it is first desired to secure'a guide or adapter H to the upper end of the packer body 10a, to facilitate subsequent running of a string of tubing G, or other well tools, into or through the set packer-A. As shown in the drawings, this guide may be attached to the lower end of a tubing string. The'gui'de H itself includes a main body portion 10 having a lower frusto-conical inn'er guide surface 101 diverging in' a downward direction, and also an upper tapered or frusto-conical guide surface 102 diverging in an upward direction. This guide has an inner bore or passage 103 which is slightly greater in diameter than the outside diameter of the tubing string G secured to it. v

The tubing string G is attached to the guide H initially by a releasable latching device. Thus, the upper portion of the guide adjacent the upper tapered guide surface 102 is enlarged in inside diameter to provide an annular pocket 104 and form an annular shoulder 105 facing in an upward direction. A snap, coupling or latch ring 106 is held partly in the pocket 104 by a shear screw 107 which extends through the guide body 100 and is threaded into a thickened portion of the ring diametrically opposite the split 108 of the ring (see Fig. 2). The remainder of the ring extends into a peripheral groove 109 formed between a lower tubing string sub 110 and an upper sub 111 threaded onto the former member. The split ring 106 tapers gradually from its mid portion receiving the shear screw towards its ends defining the split 108, the normal unrestrained inside diameter of the ring being but slightly greater than the diameter of the groove base 112.

The ring 106, when unrestrained, occupies the position illustrated in Fig. 3, with its periphery disposed entirely within the confines of the groove 109, allowing no projecting portions that may tend to hang up on other elements in the well bore. When the guide H is to be coupled to the tubing string G, the shear screw 107 is inserted through the guide body 100 and is threaded into the bore 113 of the ring. Tightening of the screw 107 pulls the ring 106 outwardly, the ring expanding upon being pulled over the groove base 112 until the medial portion of the ring is resting upon the guide shoulder 105, and with the inner portion of the ring disposed within the peripheral groove 109. With the parts in this position, any downward thrust imposed upon the tubing string G is not transmitted through the shear screw 107, but passes through the ring 106 directly into the guide body 100. However, assuming that the guide body is held from moving upwardly, an upward thrust on the tubing string G will cause the lower side of the peripheral groove to engage the ring 106 and impose an upward shearing force on the screw 107. Assuming that the screw is sheared by such upwardly directed force, the ring 106 will then be free from restraint by the screw and will snap inwardly completely into the groove 109, in view of the spring force in the snap ring that has been imparted to it upon being moved laterally by the screw 107 to coupling position upon the guide shoulder 105 (see Fig. 3).

The guide H, coupled to the tubing string G in a mannot described above and as depicted in Fig. 1, is to be latched onto the upper end of the tubular packer body 10a. To accomplish this purpose, the upper end of the packer body is provided with a plurality of annular downwardly facing ratchet teeth 114 on its periphery. The lower portion of the guide body adjacent its lower guide surface 101 has a split ratchet sleeve or ring 115, which is generally similar to the locking sleeve 25 of the packer. This sleeve 115 has internal annular ratchet teeth 116 companion to the body ratchet teeth 114, and is provided with cam surfaces 117 cooperable withcompauion cam surfaces 118 formed in the guide body 100. These cam surfaces 117, 113 taper in a downward and inward direction.

The split ratchet sleeve 115 is he within an annular pocket 119 formed in the lower portion of the guide body 100 by a bushing or metallic sleeve 120 encompassing the lower sub 110 and disposed within an annular groove 121 in the guide body. The upper end of this groove communicates with one or more bleeder holes 122, to prevent the entrapment of fluids or foreign substances in the annular groove-121. The bushing 120 is disposed across the inner-teeth116 of the ratchet sleeve 115, to.

preclude loss of the latter from the guide body 100, by one or more shear screws 123 extending through the body and into the bushing 120. The bushing itself terminates at or slightly above a horizontal plane through the uppermost portion of the lower guide surface 101, so as not to interfere with the guiding function of the latter.

The guide and sub combination is arranged as illustrated in Fig. 1, with the shear screw or screws 123 securing the bushing to the guide, and with the latch or snap ring 106 held in coupling relation to the guide H and

subs

110, 111 by the shear screw 107. The upper sub 111 is screwed onto the lower end of the tubing string G and the tubing string lowered in the well bore. When the upper end of the packer body 10a is reached, the lower tapered guide surface 101 tends to center the guiding device with respect to the upper end of the body, the bushing 120 coming to rest on the upper end of the body, with the lower end a of the sub 110 disposed centrally of the packer body axis. This lower end preferably has an exterior downwardly converging surface to facilitate entry of the tubing string in the packer body 10a, as well as in the guide itself.

When the bushing comes to rest on top of the body 10a, a downward force is imposed on the tubing string G which is transmitted through the upper sub 111 to the snap ring 106. This force passes from the snap ring directly to the guide shoulder 105 Without being imposed on the shear screw 107. However, the force is transmitted from the guide body to the lower shear screw or screws 123, this force, when of sufficient value, shearing the latter elements and moving the guide body 100 downwardly over the upper portion 114 of the packer body 10a. During such downward movement, the ratchet sleeve 115 can ratchet over the annular body teeth 114a until the bottom of the annular groove 121 or lower shoulder on the guide body 100 engages the upper end of the bushing 120. The internal annular ratchet teeth 116 on the ratchet sleeve 115 then engage the body teeth 114 and preclude upward movement of the ratchet sleeve. This sleeve also holds the guide body 100 from upward movement, since any tendency for the latter to move upwardly is prevented by its cam faces 118 wedging against the external cam faces 117 on the ratchet sleeve 115, and urging the latter more firmly into the body ratchet teeth 114.

If a sutficient upward strain is then taken upon the tubing string G, it will be transmitted through the lower side of the peripheral groove 109 to the snap ring 106. Since there is no upper guide body shoulder engaging the snap ring, this upward force is transmitted to the shear screw 107. When sufiicient, the shear screw 107 is disrupted, which frees the tubing string G from the adapter H. However, the adapter H will remain coupled to the body 10a, since its downward movement is prevented by engagement with the bushing 120, which, .in turn, rests upon the upper end of the body 10a; and its upward movement is prevented by the lock sleeve 115.

The tubing string G may now be withdrawn from the well bore B, if desired. However, a suitable sealing device is incorporated in the tubing string, to enable the latter to be run downwardly within the

packer body

10, 10a and be placed in sealing engagement with the body wall without the necessity for another round trip in the well bore. It is for this reason that the snap ring 106 is so designed as to retract completely within the confines of the sub groove 109 after the shear screw 107 is disrupted (Figs. 3, 5, 6). This retraction will enable the tubing string G to be lowered through the adapter H and into the packer body passage 32, to effect sealing engagement between the

packer body

10, 10a and the tubing string.

The sealing device may be incorporated on

tubing subs

131, 132 that actually form'part of the tubing string G.

Thus; an upper sub 131 maybe threaded onto the lower end of a tubing section, and this upper sub is', in turn, threaded into a bottom sub 132 which is threaded into the upper sub portion 111 of the guiding device H. The top and

bottom tubing subs

131, 132 have oppositely facing shoulders 133 defining an elongate circumferential groove 13% receiving a packing unit, which includes downwardly facing chevron type packing rings 135 with intervening metallic spacer rings 136, and also upwardly facing chevron type packing elements 137 and intervening metallie spacer rings 138.

After the guide H has been latched or coupled to the upper end of the body Ella and the snap ring 166 released from the guide, the tubing string G may be lowered to position the latching

subs

116, 111 and the

tubing subs

131, 132 entirely within the packer body passage 32, and with the chevron type seals 135, 137 in sealin engagement with the inner wall of the packer body. Such downward movement and proper location of the seals may be limited and determined by engagement of a locator sub 139 on the tubin string G with the upper tapered guide surface le'lZ of the adapter guide body tilt (see Fig. 6).

With the tubing string G in leakproof relation to the packer body in, lilo, fluids may now move from the well formation below the packer through the body passage 32, and into the tubing string G, to be conducted to the top of the well bore. Conversely, fluids may be pumped down the tubing string G and through the well packer A.

At any time, the tubing string G may be removed from the well packer A and retrieved from the hole B. Subsequent lowering of the tubing string with proper sealing elements thereon, such as the chevron packing assembly 135, 137 disclosed, can be had with assurance that the tubing string will properly enter the well packer. The lower end lllla of the tubing string will engage the upper tapered surface N2 of the guide H, which will steer the tubing string centrally into the guide and down into the passage 32 through the well packer by the upper guiding surface 162.

The inventors claim:

1. In apparatus of the character described: a well tool having a body; means adapted to form part of a runningin string to be lowered in a well bore containing said well tool; a guide; a latch on said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body; and means detachably securing said guide to said means and enabling said running-in string means to be released from said guide after coupling of said guide to said body.

2. In apparatus of the character described: a well tool having a body; means adapted to form part of a runningin string to be lowered in a well bore containing said well tool; a guide; a latch on said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body; and readily disruptable means detachably securing said guide to said runningdn string means and enabling said running-in string to be released from said guide after coupling of said guide to said body.

3. In apparatus of the character described: a well tool having body; a member adapted to form part of a running-in string to be lowered in a well bore containing said Well tool, said member having a peripheral groove; a guide; an expansible and contractible' ring in said groove; frangible means securing said ring to said guide; and a latch in said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body.

4. In apparatus of the character described: a well tool having a body; a member adapted to form part of a running-in string to be lowered in a well bore containing said well tool, said member having a peripheral groove; a guide; an expansible and contractible ring in said groove; frangible means securing said ring to said guide with said ring engaging a shoulder in said guide;

a' latch in said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body; said frangible means being disruptable after coupling of said guide to said body to allow said ring to retract completely within said groove.

5. in apparatus of the character described: inner and outer members; said inner member having a circumferential groove therein in its outer periphery and said outer member having a shoulder; an expansible and inherently contractible ring in said groove and resting upon said shoulder; and frangible means securing said ring in expanded condition to said outer member; disruption of said frangible means allowing inherent retraction of said ring substantially entirely into said groove and out of engagement with said shoulder.

6. In apparatus of the character described: a well tool having a body; a member adapted to form part of a running-in string to be lowered in a well bore containing said well tool; a guide surrounding said member; a latch on said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body; said member having a circumferential groove therein and said guide having a shoulder; an expansible and contractible ring in said groove and resting upon said shoulder; and frangible means securing said ring to said guide; disruption of said frangible means allowing retraction of said ring out of engagement with said shoulder.

7. In apparatus of the character described: a well tool having a body provided with a passage; a first member adapted to form part of a running-in string to be lowered in a well bore containing said well tool; a tubular member secured to the upper end of said first member; seal means on said tubular member for sealing engagement with said body; a guide surrounding said first memher; a latch on said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body; and means detachably securing said guide to said first member and enabling said first member to be released from said guide after coupling of said guide to said body, detaching of said detachable means allowing said first member and tubular member to be moved into said body passage to place said seal means in sealing engagement with said body.

8. In apparatus of the character described: a well tool having a body provided with a passage; a first member adapted to form part of a running-in string and having a peripheral groove; a tubular member secured to the upper end of said first member and having sealing means thereon; a guide; an expansible ring in said groove; frangible means securing said ring to said guide; and a latch in said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body.

9. In apparatus of the character described: a well tool having a body provided with external teeth on its upper portion; a member adapted to form part of a running-in string to be lowered in a well bore containing said well tool; a guide secured to said member; latch means on said guide and having an inner face adapted to engage said body teeth; protective means adapted to engage said body and disposed across the inner face of said latch means to hold said latch means in ineffective position in said guide; releasable means detachably securing said protective means to said guide, said releasable means being released upon engagement of said protective means with said body to enable said guide to move said latch means over said body; and means on said guide engaged by said protective means to limit movement of said latch means over said body to a position locating said inner face opposite and inc'oupling engagement with said external teeth of said body.

10. In apparatus of the character described: a well tool having a body provided with external teeth on its upper portion; a member adapted to form part of a running-in string to be lowered in a well bore containing said well tool; a guide secured to said member; latch means on said guide and having an inner face adapted to engage said body teeth; protective means adapted to engage said body and disposed across the inner face of said latch means to hold said latch means in ineffective position in said guide; releasable means detachably se curing said protective means across the inner face of said latch means, said releasable means being released upon engagement of said protective means with said body to enable said guide to move said latch means over said body; and means on said guide engaged by said protective means to limit movement of said latch means over said body to a position locating said inner face opposite and in coupling engagement with said external teeth of said body.

11. in apparatus of the character described: a well tool having a body provided with external teeth on its upper' portion; a member adapted to form part of a running-in string to be lowered in a well bore containing said well tool; a guide secured to said member; latch means on said guide and having an inner face adapted to engage said body teeth; protective means adapted to engage said body and disposed across the inner face of said latch means to hold said latch means in inefiective position in said guide; releasable means detachably securing said protective means to said guide below a stop portion on said guide, said releasable means being released upon engagement of said protective means with said body to enable said guide to move said latch means over said body and to locate said inner face opposite and in coupling engagement with said external teeth of said body when said step portion engages said protective means.

12. in apparatus of the character described: a well tool having a body; means adapted to form part of a runningin string to be lowered in a well bore containing said well tool; a guide; a latch on said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body against upward movement with respect thereto; and means releasably securing said running-in string means to said guide, said securing means being released in response to upward movement of said running-in string means after coupling of said guide to said body.

13. In apparatus of the character described: a well tool having a body; means adapted to form partof a runningin string to be lowered in a well bore containing said well tool; a guide; a latch on said guide movable over the upper portion of said body and into coupling engagement therewith to secure said guide to said body against upward movement with respect thereto; means releasably securing said running-in string means to said guide, said securing means being released in response, to upward movement of said running-in string means after coupling of said guide to said body; and means for transmitting thrust in a downward direction between said running-in string means and said guide without imposing said thrust on said releasable means.

References Cited in the file of this patent UNITED STATES PATENTS 1,370,447 Hovis Mar. 1, 1921 1,827,842 Getty Oct. 20, 1931 2,051,713 Howard Aug. 18, 1936 2,178,999 Scott Nov. 7, 1939 2,189,703 Burt et al. Feb. 6, 1940 2,313,263 Rea Mar. 9, 1943 2,315,921 Baker Apr. 6, 1943 2,401,119 Taylor May 28, 1946 2,665,763 Baker Jan. 12, 1954 2,671,512 Ragan et a1. Mar. 9, 1954