US3102594A

US3102594A - Retrievable plug for subsurface well tool passage

Info

Publication number: US3102594A
Application number: US854413A
Authority: US
Inventors: Talmadge L Crowe
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1959-11-20
Filing date: 1959-11-20
Publication date: 1963-09-03
Anticipated expiration: 1980-09-03

Description

Sept. 3, 1963 T. L. CROWE 3 4 RETRIEVAB LE PLUG FOR SUBSURFAUE WELL TOOL PASSAGE Filed Nov. 20, 1959 3 Sheets-Sheet 2 w 0m w em W 6 7 o] T L A B a M 7 3 0 2:3? ad/ii my. \nk g B g 4 r 7// gm Q N T 4 Sept. 3, 1963 T- L. CROWE 7 RETRIEVABLE PLUG FOR SUBSURFACE WELL TOOL PASSAGE Filed NOV. 20, 1959 5 Sheets-Sheet 3 INVENTOR.

firroen/sys.

United States Patent 3,102,594 RETRIEVABLE PLUG FOR SUBSURFACE WELL TOOL PASSAGE Tahnadge L. Crowe, Houston, Tex., assignor to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of California Filed Nov. 20, 1959, Ser. No. 854,413 16 Claims. (Cl. 166-125) The present invention relates to subsurface well bore apparatus, and more particularly to subsurface apparatus of the retrievable type.

An object of the invention is to provide an apparatus adapted to close the passage through a well packer or other tool disposed in a well bore, the apparatus being adapted to be run in the well bore for the purpose of being secured to the well pacloer, and also being releasable from the well packer and retrievable from the well bore, all in a single trip of the apparatus in the well bore. In a more limited sense, the apparatus can be run in the well bore on another tool, such as a retrievable squeeze packer, the apparatus being secured to the well packer, the other tool then being released from the apparatus for the performance of a desired operation in the well bore, and then recoupled to the apparatus to vbvithdraw it from the well packer to the top of the well ore.

Another object of the invention is to provide apparatus of the type above indicated which can be released from the well packer, or other tool, without the necessity for rotating the apparatus. A straight line pull is all that is necessary to release the apparatus from the packer.

A further object of the invention is to provide apparatus of the type above indicated which is capable of withstanding pressure differentials in the well bore when coupled to the well packer, or other tool, from below the apparatus and also from above the apparatus.

An additional object of the invention is to readily release an apparatus of the type above indicated from the well packer, or other tool, despite the presence of a substantial pressure differential acting on vthe apparatus.

Yet another object of the invention is to provide an apparatus of the type above indicated capable of being manipulated to equalize pressures acting on it, thereby facilitating release of the apparatus from the well packer, or other tool, to which it was connected. In a more limited sense, the apparatus includes a pressure balanced valve that can be opened without the need for overcoming any pressure differential, thereby permitting the pressures both above and below the apparatus to equalize before the apparatus is released from the well packer, or other tool.

Still a further object of the invention is to provide an apparatus of the type above indicated in which a substantial portion of the apparatus can be retrieved in the event ditiiculty is encountered in releasing the entire ap paratus from the well packer, or other tool.

Another object of the invention is to provide apparatus of the type above indicated that can be releasably secured to the Well packer, or other tool, in such relationship that the possibility of foreign substances settling out of the well bore fluid and around the apparatus, which might make subsequent retrieval diflicult, is greatly minimized.

An added object of the invention is to provide an apparatus of the type above indicated which is of strong and sturdy construction, rendering it capable of being subjected safely to heavy loads or punishment, if need be, in the event, for example, that release of the apparatus from the well packer, or other tool, encounters difficulty.

This invention possesses many other advantages, and

has other objects which may be made more clearly apparent from a consideration of a term 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:

FIGURE 1 is a side elevation of an apparatus disposed in a well casing, or similar conduit string, preparatory to its being coupled to another well tool, such as a well packer;

FIG. 2 is a combined side elevational view and longitudinal section through the main portion of the apparatus disclosed in FIG. 1;

FIG. 3 is a diagrammatic view of the slot structure of the running-in and retrieving tool portion of the apparatus disclosed in FIG. 1;

FIGS. 4 and 40 together constitute a longitudinal section, with parts in elevation, of the apparatus coupled to a well packer and set in a well casing, FIG. 4a constituting a lower continuation of FIG. 4;

FIGS. 5 and 5a are views corresponding to FIGS. 4 and 4a, illustrating the release and retrieving of the packer plug apparatus from the well packer.

The apparatus A illustrated in the drawings is adapted to be lowered in a well bore or well casing 13 for the purpose of closing a central passage 10 through a well packer C previously anchored in the well easing. The apparatus A is lowered in the well casing B, and may also be removed therefrom, by means of a running-in and retrieving tool D releasably connected to the apparatus. This tool is suitably secured to a tubular string extending to the top of the well bore, or to another tool E, such as a retrievable squeeze packer, which, for example, can be of the type illustrated in US. Patent No. 2,802,534, adapted to be anchored in packed-cit condition in the well casing at any desired point therein, and which retrievable squeeze packer E is suitably secured to a tubular running-in string (not shown) extending to the top of the well bore.

The apparatus A can be run in the well casing B and coupled to the well packer C to close its central passage 10. The running-in and retrieving tool D can then be released from the apparatus A, which remains coupled to the well packer C, in order that the running-in and retrieving tool D, and the upper tubing or tool E secured thereto, can be raised the desired distance above the plug apparatus A, whereupon a suitable operation can .be performed in the well bore through use of the upper tool E. Following completion of such operation, the upper tool E and retrieving tool D are again lowered to couple the running-in and retrieving tool to the plug apparatus A, to release it from the well packer C and elevate it in the well casing B to the top of the well bore.

The well packer C illustrated by way of example in the drawings can be of any desired type. The one specifically shown somewhat diagrammatically is more particularly illustrated and described in US. Patent No. 2,624,412. It includes a central tubular body 11 having a set of segmental upper slips 12 anchored to the well casing by an upper expander 18. to prevent upward movement of the well packer in the well casing. A set of lower segmental slips v1-4 is held in anchoring engagement with the well casing by a lower expander 15 to prevent downward movement of the well packer C in the well casing B. Between the expanders is the packing structure 16, such as a rubber or rubber-like sleeve, which has been expanded into firm sealing engagement with the wall of the well casing B and also the interior of the packer body 11, to prevent fluid from flowing around the exterior of the well packer. The well packer also has a setting sleeve 17 for accomplishing the expansionof the slips and packing str-ucture against the well casing, and its body 11 has an upper threaded box 18, the threads usually being of left-hand. The specific closure or plug apparatus A illustrated is adapted to be coupled to the well pecker C through the agency of its threaded connection 18,- with the plug apparatus inserted within the central passage 10 through the body of the packer to close the same.

The packer passage closure or plug apparatus A includes an upper member or control bar 19 which is adapted to be releasablyicoupled to the running-in and retrieving tool D, extending upwardly within the slotted structure 20 of the latter (FIG. This control bar has a lateral coupling pin 21 secured thereto adapted to move within the slotted housing structure 20, which may be of any suitable type, such, for example, as shown and described in U.S. Patent No. 2,799,344, and particu larly the slot structure in FIG. 4 thereof. The lower portion of the control bar 19 is piloted within a control valve sleeve 22, to which it is secured [for joint longitudinal. movement through the agency of a safety rupturable member 23, such as a release stud, the upper end of which is threaded into the control bar and the lower end of which is threadedly secured to a bushing or stop member 24. The release stud has a central weakened section 25 at which the stud will pull apart when its disruption is required. 1

The lower end of the control bar 19 is disposed above an inwardly directed flange or stop shoulder 26 on the control sleeve 22, whereas the bushing or stop member 24 underlies such flange, to engage the latter. The corn trol sleeve 22 is piloted over the elongate body 27 of the closure or plug A, hearing against an external flange or shoulder 28 thereof. The body is initially secured to thecontrol sleeve by one or more shear screws 29 which hold the control sleeve adjacent to the body shoulder or flange 28 and across one or a plurality of side or lateral equalizing ports 30 in the body extending between a central passage 31in the body, opening through its lower end, and the exteriorof the body. Leakage of fluid through the ports 30 :is prevented by suitable side seals 32, such as rubber'or rubber-like O-rings, disposed on opposite sides of the port or ports 30 in external body grooves 33 and adapted to seal against the inner surface of the control valve sleeve 22.

The body 27 includes a lower seal sub or head 34 threaded-1y attached thereto and a bottom sub 35 threadedly or otherwise-secured to the lower end of the sub 34-; The seal sub and the bottom sub together provide an external groove 36 in which a packing structure 37 is mounted. The seal sub 34 and bottom sub 35, as well as the packing 37, have a diameter adapted to have a sliding iit with the inner wall 38 of the body 11 of the well packer, for the purpose of sealing thereagainst below its threaded box 18.

When disposed within the well packer passage 10, the plug A is prevented (from being removed therefrom until desired by a latch sleeve 39 surrounding the body '27, being movable longitudinally with respect thereto by a certain distance. The latch sleeve 39 has a plurality of oircumferentially spaced longitudinal slots 40 opening through its lower end and has threaded heads or dogs 41 formed thereon of the same pitch as the packer box thread 18 and adapted to mesh therewith. The threads 42 on the latch heads or dogs have both their upper and

lower sides

43, 44 tapered so that the threaded dogs 41 can spring inwardly when the latch sleeve 39 is moved downwardly along the packer box threads 18, as well as upwardly therealong. Such inward movement is permitted by a relief portion 45 on the plug body 27 behind the threaded heads or dogs 41 therearound. The upper unslotted portion 46 of the latch or coupling sleeve 39 4 is slidable along a cylindrical portion 47 of the body and below its external flange. or shoulder 28.

The body sub 34 has a backing or retainer surface 43 that tapers in an upward and inward direction, being adapted to coact with a companion tapered surface 49 on the lower inner end portionsof the threaded dogs 41, to expand or hold the dogs outwardly in full threaded mesh with the box threads m the well packer body 11. The distance between the retainer surface 48 and the plug body flange or shoulder 28 is substantially greater than the length of the latch or coupling sleeve 3% to permit relative longitudinal movement between the sleeve and plug body to occur, in order that the threaded heads or dogs 41 can be defletced inwardly for the purpose of bringing the sleeve 39 into coupling relation to the threaded box 18 and releasing the sleeve therefrom.

The latch or coupling sleeve 39 is retained on the body 27 by a connecting sleeve 50 which surrounds the lower portion of the control sleeve 22, having an inwardly directed flange 51 disposed above an external flange 52 on the control sleeve. The connecting sleeve 50 extends downwardly along the control sleeve flange 52 and the plug body flange 28, as well as along the coupling sleeve 39, having an inwardly vdirected flange or shoulder 53 provided on a sleeve nut 54 threadedly secured to the lower portion of the latter 50, which is adapted to engage an outwardly "directed flange or shoulder 55 at the upper portion of the latch or coupling sleeve. The connecting sleeve 50 and its nut 54 preferably have an external diameter which is only slightly less than the internal diameter of the well packer setting sleeve 17, and the lower end 56 of the nut tapers in a downward and inward direction for the purpose of seating against a correspondingly tapered upper end 57 on the well packer body 11, in effect, forming a metallic seal thereagainst when the plug apparatus A is coupled to the well packer C (FIG. 4).

The running-in and retrieving tool I), has the slotted structure 20 therewithin which has several positions of coaction with the coupling pin 21 extending laterally from the control bar 19. These positions are shown diagrammatically in FIG. 3. See also FIG. 5. Thus, position 4 represents the coupling pin 21 within the entry slot portion 58 of the slotted structure. Position 5 illustrates the pin in the locating slot portion 59. Position 6 illustrates the pin in the retrieving portion 64 of the slot. Position 1 rep-resents. the running-in position of the pin 21 in'the release portion 67 of the slot, at which time a milling guide shoe 61 having teeth 62, and which is secured to the-lower end of the housing 63 of the running-in and retrieving tool D, is releasably secured to the control bar 19 by one or more shear screws 64. At this time, it will be noted that the lower end 65 of the milling shoe is spaced above the upper end 66 of the control sleeve ('FIG. 2). Position 2 illustrates the pin 21 in the upper portion of the release slot 67 of the slotted structure, in which position-the milling shoe 6 1 will engage the upper end 66 of the control sleeve 22. Position 3 illustrates the pin 21 as it is moving relatively out of the release slot 67 and the entire slotted structure '20, for the purpose of elevating the running-in and retrieving tool D from the control bar 19, so that the former can be raised away from theplug or closure A after the latter has been inserted withinrthe packer body 11.

In the use of the apparatus heretofore described, the shear sorew'29 initially holds the valve sleeve 22 in position closing the equalizing ports 30 in the body 27 of the plug A. The safety stud 23 is also intact. The control bar 19 is inserted within the housing 63 andits slotted structure 20, the control pin 21 moving relatively up through position 4 of the entry slot portion 58 of the structure and into the locating slot portion 59, after which it is moved downwardly to engage the inclined wall 70 of the slotted structure and shift into retrieving position 6. it is then moved-upwardly and turned to the left until it enters the retrieving slot portion 67 and occupies position 2, whereupon the shear screw or screws 64 are threaded laterally in the milling guide shoe 61 until they bear lightly against the periphery of the control bar 19.

The latter is then moved slowly downwardly of the hous ing 63 and slot structure until the pin reaches the number 1 position illustrated in FIG. 3, at which time the screws 64 will be opposite a circumferential groove 71 in the control bar, enabling the screws to be threaded fully inwardly so that they are disposed within such groove. The parts are now coupled to one another in the position illustrated in FIGSv l and 2, which enables the entire apparatus to be lowered in the well casing 13' toward the well packer C previously set therewithin. Preferably, as stated above, the housing D is secured to the lower end of an upper retrievable squeeze packer B.

When the upper end of the well packer C is reached, the lower portions of the body 27 will move thereinto, the sealing structure 37 and

subs

34, 35 on opposite sides thereof passing into the packer body passage 10. When the lower end 72 of the latch sleeve 39, which is tapered in a downward and inward direction, engages the packer box threads 18, the latch sleeve is at first prevented from moving downwardly, the plug body 27 then moving downwardly thereof so that the backing or retainer surflace 48 is then disposed below the threaded dogs 41. The body shoulder 28 engages the upper end of the latch sleeve 39 and will force the latch sleeve downwardly within the threaded box 18, the tapered threads 42 of the latch dogs causing the dogs to retract inwardly and ratchet freely in a downward direction over the companion packer box threads 18. The external flange 55 at the upper end of the latch or coupling sleeve engages the connecting sleeve nut 54 and shifts the nut downwardly within the packer setting sleeve 17 until the lower tapered end 56 of the nut engages the companion tapered surface 57 at the upper end of the packer body, whereupon further downward movement of the plug apparatus A cannot occur.

Downweight is now imposed upon the entire tubing string E and the slotted structure 20 and the housing 63 of the running-in and retrieving tool D, which will shear the screws 64 securing the milling guide shoe 61 of the latter to the control bar 19, to release the housing 63 from the control bar. The housing and milling shoe can now move downwardly until the milling shoe engages the upper end 66 of the control sleeve 22, which will place the coupling pin 21 relatively in the number Z position illustrated in FIG. 3. The tubing string E and housing 63 are now elevated, which will cause the releasing slot structure 67 to slide upwardly along the pin 21, the pin moving through the number 1 position to the number 3 position and completely out of the lower end of the housing structure 63, which can then be raised the desired distance above the plug or closure apparatus A, or removed entirely from the well casing, if desired.

The parts are now in their relative positions illustrated in FIGS. 4 and 4a of the drawings, in which any pressure diflerental below the well packer C -wll act on the plug body 27 and shift it upwardly to cause its backing or retainer surface 48 to engage the companion surfaces 49 on the threaded heads or dogs 41 of the latch sleeve and hold such dogs outwardly in threaded mesh with the threads of the packer box 18. Accordingly, the passage 10 through the packer body 11 is closed against upward passage of fluid therethrough. It is also closed against downward passage of fluid therethrough and will resist fluid pressures above the well packer. Such fluid pressures will shift the plug body 2-7 downwardly, the body flange 2S engaging the upper end of the coupling sleeve 39 and causing its shoulder 55 to engage the upper end of the connecting sleeve nut 54, which is in engagement with the upper tapered end 57 of the packer body '11, thereby precluding any further down-ward movement of the plug body, which will remain in sealing engagement with the inner wall 38 of the well packer C.

If an upper tool, such as a retrievable squeeze cementing tool E, is connected to the running-in and retrieving tool D, the latter can be elevated in the well casing above the plug apparatus A and a suitable operation performed in the well bore. if a squeeze cementing operation is to be performed, the upper retrievable well packer. E will be set in packed-off condition in the well casing B in a known manner and cement slurry pumped down through the tubing string, the squeeze cementing packer and retrieving tool D, and out through the well casing B into the surrounding well bore. The plug ap paratus A in the lower packer C will prevent the fluid under pressure from passing downwardly through the well packer.

After the squeeze cementing 'or other operation has been performed, the upper squeeze cementing tool E and the running-in and retrieving tool D attached thereto are lowered, the housing structure 63' and its slot device 20 passing over the control bar 19. The pin 21 extending laterally from the latter engages the lower inclined surface of the slotted structure 20 within the housing which will guide the pin 21 toward the number 4 position illustrated in FIG. 3, the housing structure 63 then moving downwardly :over the control bar 19 until the pin is disposed in the locating slot portion 59 illustrated in FIG. 3. The operator will know that the number 5 position has been reached by virtue of the fact that further downward movement cannot occur inasmuch as the milling shoe 61 engages the upper end 66 of the control sleeve 22, which will move the plug body 27 downwardly into engagement with the upper end of the latch sleeve 39, which, in turn, engages the nut 54 of the connecting sleeve 50, that rests upon the upper tapered end 57 of the packer body.

The operator now moves the tubular string and the running-in and retrieving tool D connected thereto slowly upwardly, which will cause the inclined wall 70 of the slotted structure to engage the pin 21 and ,move the slotted structure arcuately until the pin is disposed in the number 6 position, which is the retrieving position. The taking of an upward strain onthe tubular string E and running-in and retrieving tool D will move the control bar 19 upwardly, which will carry the release stud 23, bushing 24 and control sleeve 22 upwardly. Such upward movement will first shear the screw or screws 29 securing the control sleeve to the plug body 27, in asmuch as the body is prevented from moving upwardly by the engagement of its retainer surface 48 with the dogs 41, and the fact that the dogs are thereby held in threaded engagement with the packer box threads 13. Upon shearing of the screw or screws 29, the control and valve sleeve 22 is moved upwardly of the body 27 until the lower end of the valve sleeve is located above the equalizing ports 30. Since these ports are now open, any pressure differential that may have existed above or below the well packer will now equalize through the open ports, so that there is no pressure either above or below the well packer C tending to retain the plug A coupled to it.

A continuation of the upward movement of the tubular string E and the running-in and retrieving tool D will carry the control bar 19 upwardly with it, the release stud 23 and bushing 24 carrying the control sleeve 22 upwardly until the flange 52 of the latter engages the upper flange 51 of the connecting sleeve 50, and the lower end 53 of this sleeve engaging the external shoulder 55 at the upper end of the latch or coupling sleeve 39 to move the latter upwardly of the body 2-7. Such upward movement is permitted since the upper ends 43 of the threads on the latch dogs are tapered in an upward and inward direction, which will cam the heads 41 inwardly as they ratchet past the box threads 18. At this time, the plug body 27 is separate from the control sleeve 22 because of the shearing of the screws 29. If the plug body 27 has not moved downwardly of the 7 latch sleeve 39, sothat the backing or retainer surface 48 is still engaged withthe dogs 41, the upward pull on the latch sleeve 39 will cause the dogs to shift inwardly and pinch or cam the body 27 downwardly to a released position with respect to the dogs. The latter can now retract inwardly during upward movement of the latch sleeve 39 within the threaded box 18 of the packer, the threads 42 of the dogs, as explained above, ratcheting freely over thecompanion threads of the packer body 13.

Upward movement of the entire apparatus A can continue, the upward motion being transferred from the slotted housing 63, through the control bar pin 21 to the control bar 19, and from the latter through the stud 23 and bushing 24 to thecontro-l sleeve 22, the flange 52 of the latter engaging the upper flange 51 on the connecting sleeve 50, the lower nut 54 of which, in turn engages the external shoulder 55 of the latch sleeve 39 to carry the latch sleeve upwardly. The upper end of the latch sleeve, in turn, engages the flange 28 of the plug body 27 to elevate the plug body (FIGS. and 5a). During all this time, of course, the coupling pin 21 on the control bar remains in the retrieving slot portion 60 of thehousing structure 20. The entire plug apparatus A can now be removed fromthe well casing by means of the tubular running-in string E, leaving an open passage through the well packer C.

In the eventNof difiicultybeing encountered in releasing the latch sleeve 39 from the well packer C, a

' substantial strain can be taken on the apparatus in attempting to effectxsuch release since the release stud 23"can be made to withstand substantial forces (for example, 20,000 lbs. before being pulled apart). However, if release :of the latch sleeve from the packer body still cannot be effected, then the running-in and retrieving tool D and the upper portion of the plug apparatus can still be removed from the Well casing, since a sufficient upward pull .will effect a disruption of the release stud at its weakest section 25, freeing the control bar 19 from the control sleeve 22' and allowing the control bar to be moved upwardly with the running-in and retrieving tool D in the well casing B, for complete withdrawal from the upper end of the latter.

In the event of disruption of the release stud 23, a suitable fishing tool (not shown) can then be lowered in the well casing and an overshot'portion at the lower end of the latter moved over the control sleeve 22, which preferably has the external threads 81 thereon for coaction with the usual fishing threads formed on the overshot (not shown). The necessary jarring action can now be imposed in a known manner on the fishing apparatus and the plug A, seeking to effect release of the latch sleeve 39 from the box 18 and withdrawal of the entire plug apparatus from the well casing.

It is to be understood that the disruption of the release stud 23 is only necessary under emergency conditions in the unusual case in which the latch sleeve 39 cannot be released. Ordinarily, the sleeve 39 is released in the manner described above, allowing the entire plug apparatus to be removed from the well packer C and i from the well casing B through use of the running-in and retrieving tool D.

Difficulty-in elfecting release of the latch sleeve 39 from the threaded box 18 of the well packer is minimized 'by preventing the settling of solid materials in thethreaded region of the apparatus. As pointed out above, the connecting sleeve 50 and its not 54 preferably make a fairly close fit with the inner wall of the'setting sleeve 17 of the well packer, such as disclosed in FIG. 4. At the same time, the lower end 56 of the connecting sleeve is making a metal-to=metal seal with the upper end 57 of the packer body 11. Accordingly, there is a minimum of space through which any solid substances in the fluid within the well casing B above the well packer C can settle out and become deposited within the packer body 8 11 and particularly around its threads 18 and the threads 42 of the latch sleeve. The flange 28 of the latch sleeve 39 itself makes a seal against the upper end of the connecting sleeve nut 54, and the upper end 46 of the sleeve also makes a fairly close fit with the cylindrical surface 47 of the plug body 27.

As was also pointed out above, if any pressure difierentials exist in the- Well casing, as for example, below the well packer C, which would tend to hold the plug body 27 in an upward position and retain the latch sleeve 39 coupled to the threads 18 of the packer body, such pressures are automatically equalized with the present plug apparatus, inasmuch as the taking of the upward strain on the connector sleeve 22 shears the screws '29 and moves the, sleeve above the equalizing ports 30, which provides an open passage frombelow the well packer C, through the plug passage 31 and out throughthe ports 30, and also through a side port or ports '82 in the connecting sleeve 50, and tothe well'casing region above the well packer. In this manner, the pressuresabove and below the well packer can be equalized so that no pressure differentials are available tending to hold the plug apparatus anchored to the well packer.

The equalizing ports 30 can be opened without even requiring that the control sleeve 22 resist any differential pressures. It is to be noted that the lower portion of the control sleeve and its engagement with the seals 32 on opposite sides of the equalizing ports 30 constitute a balanced valve arrangement, in which there are no differential areas present over. which the fluid pressure can act. Even with very high fluid pressures on one side of the well packer C, such as below the well packer, the control sleeve 22 can be moved upwardly without the necessity for overcoming any pressure differentials.

The plug apparatus A is of a strong and sturdy construction and can, if desired, be made of alloy steels, rendering it capable of withstanding heavy punishment, such as might be encountered, on occasion, in the event thata fishing operation is necessary. The parts will with stand heavy loads without breaking. Any disruption that does occur is at a predetermined point, as at the weakened section 25 of the release stud 23.

The inventor claims:

1. In retrievable closure apparatus adapted to be releasably secured to a well tool having a passage and dis: posed in a well bore: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means on and movable longitudinally along said body adapted to releasably engagethe Well tool to secure said body to the well tool; and means movable longitudinally along. said body and longitudinally with respect to said latch means into engagement with said latch means to elevate said latch means along said body and release said latch means from the well tool.

2. In retrievable closure apparatusadapted to be 'releasably secured to a well tool having a passage 'and'dis posed in a well bore: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means on said body adapted to releasably engage the well tool to secure said body to the well tool;- retainer means on said body engageable with said latch means to hold said latch means engaged with the-well tool; and means movable longitudinally along said body and longitudinally with respect to said latch means into engagement with said latch means to elevate said latch means with respect to said retainer means and release said latch means from the well tool.

3. In retrievable closure apparatus adapted to be releasably secured to a well tool disposed in a well bore and having a passage surrounded by a threaded box: -a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means movable inwardly and outwardly on said body and having a threaded portion comp-anion to the threaded box and meshable therewith to secure the body to the well tool; said latch means having means thereon for moving said latch means laterally inwardly whereby said latch means can move without rotation downwardly along the threaded box to insert its threaded portion Within the threaded box; said latch means having means thereon for moving said latch means laterally inwardly whereby said latch means can move without rotation upwandly along the threaded box; means on said body engage-able with said latch means to hold its threaded portion in mesh with the threaded box; and means for elevating said latch means without rotation along said body to release and withdraw said thread ed portion from the threaded box.

4. In retrievable closure apparatus adapted to be releasably secured to a well tool disposed in a well bore and having a passage surrounded by a threaded box: a body adapted to be disposed in the well tool passage in sealing relation to the Well tool; latch means movable inwardly and outwardly on said body and having a threaded portion companion to the threaded box and meshable therewith to secure the body to the well tool; the lower side of the thread of said threaded portion being tapered in a downward and inward direction and the upper side of the thread of said threaded portion being tapered in an upward and inward direction whereby said threaded portion engages the threaded box to move the latch means inwardly and disengage said threaded portion from the threaded box upon upward and downward movement of said latch means in the threaded box; means on said body engageable with said latch means to hold its threaded portion in mesh with the threaded box; and means for elevating said latch means without rotation along said body to release and withdraw said threaded portion from the threaded box.

5. In retrievable closure apparatus adapted to be releasably secured to a well tool having a passage and disposed in a well bore: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means on and movable longitudinally along said body adapted to releasably engage the well tool to secure said body to the well tool; means movable longitudinally along said body and longitudinally with respect to said latch means into engagement wih said latch means to elevate said latch means along said body and release said latch means from the well tool; said body having a fluid passage extending between points above and below the point of sealing relation of said body to the well tool; and valve means closing said body passage to prevent downward flow of fluid therethrough and adapted to be shifted to a position opening said body passage to permit downward flow of fluid therethrough.

6. In retrievable closure apparatus adapted to be releasably secured to a well tool having a passage and disposed in a well bore: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means on said body adapted to releasably engage the well tool to secure said body to the well tool; means movable along said body to elevate said latch means on said body and release said latch means from the well tool; said body having a fluid passage extending from a point below the point of sealing relation of said body to the well tool and including a side port above said point of sealing relation; and a sleeve valve closing said port and adapted tobe shifted along said body to a position opening said port and body passage.

7. In retrievable closure apparatus adapted to be releasably secured to a well tool having a passage and disposed in a well bore: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means on said body adapted to releasably engage the well tool to secure said body to the well tool; means movable along said body to elevate said latch means on said body and release said latch means from the well tool; said body having a fluid passage extending from a point means to release said latch means from the well tool.

8. In retrievable closure apparatus adapted to be releasably secured to a well tool having a passage and disposed in a well bore: a body adapted to be disposed in the Well tool passage in sealing relation to the Well tool; latch means on and movable longitudinally along said body adapted to releasably engage the well tool to secure said body to the well tool; means movable longitudinally along said body and longitudinally with respect to said latch means into engagement with said latch means to elevate said latch means along said body and release said latch means from the well tool; and means releasably securing said latch elevating means to said body to prevent release of said latch means from the well tool. 7 9. In retrievable closure apparatus adapted to be releasably secured to a well tool having a passage and disposed in a well bore: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means on said body adapted to releasably engage the well tool to secure said body to the well tool; means movable along said body to elevate said latch means on said body and release said latch means from the well tool; said body having a fluid passage extending between points above and below the point of sealing relation of said body to the Well tool, said latch elevating means including valve means closing said body passage and adapted to be shifted to a position opening said body passage; and means releasably securing said latch elevating means to said body to prevent release of said latch meansfrom the well tool and to hold said valve means in closed position. r

10. In retrievable closure apparatus adapted to be releasably secured to a Well tool disposed in a well bore and having a passage surrounded by a threaded box: a body adapted to be disposed in the Well tool passage in sealing relation to the well tool; latch means movable inwardly and outwardly on said body and having a threaded portion companion to the threaded box and meshable therewith to secure the body to the well tool; the lower side of the thread of said threaded portion being tapered in a downward and inward direction and the upper side of the thread ott said threaded portion being tapered in an upward and inward direction whereby said threaded portion engages the threaded box to move the latch means inwardly and disengage said threaded portion from the threaded box upon upward and downward movement of said latch means in the threaded box; means on said body engageable with said latch means to hold its threaded,

portion in mesh with the threaded box; means for elevating said latch means: without rotation along said body to release and withdraw said threaded pontion from the threaded box; said body having a fluid passage extending between points above and below the point of sealing relation of said body to the well tool; said latch elevating means including valve means closing said body passage and adapted to be shifted to a position opening said body passage upon upward movement of said latch elevating means to release said latch means zfirom the threaded box.

11. In retrievable closure apparatus adapted to be re- ;leasa'bly secured to a Well tool disposed a well bore and having a passage surrounded by a threaded box: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means movable inwardly and outwardly on said body and having a threaded portion companion to the threaded box and mesh-able therewith to secure the body to the well tool; the lower side of the thread of said threaded portion being tapered in a downward and inward direction and the upper side of 11 the thread of said threaded portion being tapered in an upward and inward direction whereby said threaded portion engagesthe threaded box to move the latchtmeans inwardly and disengage said threaded portion from the threaded box upon upward and downward movement of said latch means in the threaded box; means on said body engageable with saidlatch means to hold its threaded portion in mesh with the threaded box; means for elevating said latch means without'rotation along said body to release and withdraw said threaded portion from the threaded box; said body having a fluid passage extending from a point below the point of sealing relation of said body to the well tool and including a side port above such point of sealing relation; said latch elevating means including a sleeve valve closing said port and movable upwardly along said body to a position opening said port in response'tompward movement of said latch elevating meansto release said threaded portion from the threaded box; 1

12. In retrievable closure apparatus adapted to be releavably secured to a well tool having a passage and disposed in a well bore: a body adapted to be disposed in thewell tool passage in sealing relation to the well tool; latch means on and'movable longitudinally along said body adapted to releasably engage the well tool to secure said body to the Well tool; means movable longitudinally along said body and longitudinally with respect to said latch means into engagement with said latch means to elevate said latch means along said body and release said latch means from the well tool; and means secured to said latch elevating .means and adapted to be coupled to a running-in string,

13. Ina retrievable closure apparatus adapted to be releasably secured to a well tool having a passage and disposed in a well bore: a body adapted to be disposed in the well tool passagesin sealing relation to the well tool; latch means on and movable longitudinally along said body adapted to releasably engage the well tool to secure said body .to'the well tool; means movable longitudinally along said .body and longitudinally with respect to said latch means into engagement with said latch means to elevate said latch means along said body and release said latch means from the well tool; running-in means adapted tobecoupled to la running-in string; and means releasably securing said running-in means to said latch elevating means to permit said running-in means to be released from said latch'elevating means and removed from the well bore.

14. Inretrievableclosure apparatus adapted to be releavably secured to a well tool disposed in a well bore and-baving'a passage surrounded by a threaded box: a bodyadapted to be disposed in the well tool pass-age in sealing. relation to the well tool; latch means movable inwardly and outwardly on said body and having a threaded portion companion to the threaded box and meshable thcrewithto secure the body to the Well tool; the lower side of the threadof said threaded portion being tapered in a downward and inward direction and the upper side of the:thread of said threaded portion being tapered in anupward and-inward direction whereby said threaded "portion engages the threaded box to move the latch means inwardly and disengage said threaded portion from the threaded box iupon upward and downward movement of said latch means in the threaded box; means on said body engageable with said latch means to hold its threaded portion-in mesh with'the threaded box; a control member; means releasably securing said control member to said body; and a connecting sleeve engageable with said control member and latch means for elevating said latch means :With respect to said body and the threaded box upon release ,of said releasable means in response to elevation of said control member.

- I 15. Inretrievable :closure apparatus adaptedto be releasably secured to a well tool disposed in a well bore and having a passage surrounded by a threaded box: a

body adapted to be disposed in the well tool passage'in side of the thread of said threaded portion being tapered in an upward and inward direction whereby said threaded portion engages the threaded box to move the latch means inwardly and disengage said threaded portion from the threaded box upon upwardand down wardmovement of said latch means in the threaded box; means on said body engageable with said latch means to hold its threaded portion in mesh with the threaded box; said body having a fiuid passage extending from a point below the point of sealing relation of said body to the well tool and including a side port above such pointof sealing relation; 2.

control member; means releasablyv securing said control member to said body and over said port to close said port; and a connecting sleeve engageable with said control member and latch means, whereby elevation of said control member releases said releasable means to permit said control member to move upwardly of said body to open said port and elevate said latch means with respect to said body and the threaded box to release said latch means from the threaded box.

16. In retrievable closure apparatus adapted to be releasably secured to a. well tool disposed in a well bore and having a passage surrounded by a threaded box: a body adapted to be disposed in the well tool passage in sealing relation to the well tool; latch means movable inwardly land outwardly on said body and having a threaded portion companion to the threaded box and meshable therewith to secure the body to the well tool;

the lower side of the thread of said threaded portion being tion from the threaded box upon upward and down- Ward movement of said latch means in the threaded box; means on said body engageable with said latch means to hold its threaded portion in mesh with the threaded box; said body having a fluid passage extending from a point below the point of sealing relation of said body to the well tool and including a side port above such point of sealing relation; a control member; means releasably securing said control member to said body and over said port to close said port; a connecting sleeve engageable with said control member and latch means, whereby elevation of said control member releases said releasable means to permit said control member to move upwardly of said body to open said port andelev-ate said latch means with respect to said bodyand the threaded box to release said latch means from the threaded box; running-in means adapted tobe coupled to a running-in string; and means releasably securing said running-in means to said control member to permit said running-in means to be released from said control member and removed from the well bore.

References Cited in the file of this patent UNITED STATES PATENTS Baker et a1. July 26, 1955 (Other references on following page):-

13 UNITED STATES PATENTS Knox Mar. 6, 1956 Baker Mar. 6, 1956 Baker June 19, 1956 Bielstein Jan. 1, 1957 5 Muse July 16, 1957 14 Bostock et a1 Apr. 28, 1959 Rogers Jan. 12, 1960 Schramm Nov. 15, 1960 7 Medford Nov. 22, 1960 Crowe et a1 Oct. 24, 1961

Claims

1. IN RETRIEVABLE CLOSURE APPARATUS ADAPTED TO BE RELEASABLY SECURED TO A WELL TOOL HAVING A PASSAGE AND DISPOSED IN A WELL BORE: A BODY ADAPTED TO BE DISPOSED IN THE WELL TOOL PASSAGE IN SEALING RELATION TO THE WELL TOOL; LATCH MEANS ON AND MOVABLE LONGITUDINALLY ALONG SAID BODY ADAPTED TO RELEASABLY ENGAGE THE WELL TOOL TO SECURE SAID BODY TO THE WELL TOOL; AND MEANS MOVABLE LONGITUDINALLY ALONG SAID BODY AND LONGITUDINALLY WITH RESPECT TO SAID LATCH MEANS INTO ENGAGEMENT WITH SAID LATCH MEANS TO ELEVATE SAID LATCH MEANS ALONG SAID BODY AND RELEASE SAID LATCH MEANS FROM THE WELL TOOL.