US3137349A

US3137349A - Systems of expansible well tools

Info

Publication number: US3137349A
Application number: US21333A
Authority: US
Inventors: Henry U Garrett
Original assignee: Udell Inc
Current assignee: Udell Inc
Priority date: 1960-04-11
Filing date: 1960-04-11
Publication date: 1964-06-16
Anticipated expiration: 1981-06-16

Description

June 16, 1964 H. u. GARRETT SYSTEMS OF EXPANSIBLE WELL TOOLS INV EN TOR June 16, 1964 H. u. GARRETT 3,137,349

SYSTEMS OF EXPANSIBLE WELL TOOLS Filed April ll, 1960 3 Sheets-Sheet 2 INV EN TOR.

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UnitedStates Patent O SYSTEMS OF EXPANSIBLE WELL TOOLS Henry U. Garrett, Longview, Tex., assignor to Udell, Inc., Longview, Tex., a corporation of Texas Filed Apr. 11, 1960, Ser. No. 21,333 14 Claims. (Cl. 166-196) Thisrinvention relates to improvements inwell tools, and refers more particularly to tools made up in the tubing string of a Well that are expanded to engage the well casing, systems including such' tools and the method of making such installations.

It is frequently desirable in present day equipment of wells for the production of oil and gas to utilize several packers in a single well to seal between'the usual oil string of casing and the well tubing. For example, it is sometimes desirable to seal both above and below a producing formation in a Well that is producing only from a single formation and in other wells producing from several formations it is usually necessary to provide a seal between a tubing and casing between the various producing formations.

With equipment that has been available for this pur` pose, trouble has been experienced in setting the packers, when a series of them are employed, with being certain that the right portion of the weight of the tubing is supported by each packer. This trouble is experienced because of the manipulation of the tubing that is required in setting the packers and any tubing hold-down devices that are employed. Forexample, let us consider a well having three packers where the operator desires to have 10,000 pounds ofthe tubing weight carried by each packer.l

The mere fact that the weight indicator at the surface indicates that on completion of the setting of the packers that 30,000 pounds of the weight of the tubing string had been released (over and above the weight of the tubing string beneath the lowermost packer) does not meanthat this weight has beenevenly distributed between the three packers. While it is not critical that each packer have a load imposed on it that is known to within a few pounds, nevertheless the load supported by each packer must be sufficient to provide the seal between the tubing and cas-l ing and should be predetermined within practical oil eld tolerances. Heretofore, the division of the weight of the tubing string between the packers has frequently been such that one or moreof the packers has not had sufficient load, on it to provide the seal. Evenif the packers are properly loaded when set, the setting ofthe holddown, Where one is used, may disturb the distribution of the load to the extent that a failure occurs'. In any event, the operator has no Way to determine just whatvload is supported by the various components of the installation.

It is an object of this invention to provide a well tool y invention and from the claims.y

adapted for inclusion in a tubing string with an expansible means, for example a packer or a holddown,' which can be controlled from the surface in its setting, without requiring any manipulations of theltubing string that can affect the Weight of the tubing string that has previously been imposed on a previously set packer. Another object is to provide a Well tool having rela tively telescoping parts for actuating an expansible means, for example a packer or a hold-down with a means for holding the parts in a relative position with the packing means contracted, and a means for releasing the' holding means by an operation controllable from the surfacel which is independent of any manipulation of the tubing string.

3,137,349 Patented June 16., 1964 a packer lor hold-down, with a pressure operated means 'surface without affecting the amount of the weight of previously set device. y

Another object is to provide a well tool, as apacker or a hold-down, with a lock means to prevent its premature'setting in which a wire line operation is used to release the lock whereby the packer may be set with a predetermined load by releasing a predetermined portion of the tubing weight to set the packer.

Another object is to provide a well tool, asa packer or a hold-down, with a lock means having a fluid filled chamber which holds the tool contracted,with means to vent the chamber to release the lock without a maniputhe` tubing string that is borne by'the well tool or any lation of thetubing string that can alfect the load on vprovided on the tubing string above the packers so that the loading on the packers will not be disturbed.

Another object is to' provide a tubing system with a series of well packers thereon in which a selected load may be placed on each of the packers and a hold-down is provided on the tubing string above the packersso that the loading on thepackers will not be disturbed, and in which the portion of the tubing above the hold-down may be released for performing various -well operations.

' Another object is to provide a method for setting a Ytubing string with va plurality of packers therein so that eachk of the packers will support a selectedv portion of the Weight of the tubing string.

' Another object is to provide a method of installing a tubing string with a plurality of packers therein with a selected'portion of the tubing weight carried by each ofv theY packers in which a substantial portion rof the tubing above the packers may be removed without disturbing the loading on the packers. i

v Other and further objects of the invention will appear from the description of a preferred embodiment of the In the accompanying drawings which form a part .of the instant specification and wherein like reference numerals areused to indicatelike parts: i I v FIGS. 1A and 1B illustrate in section a cased well bore equipped with a tubing system, including packers anda hold-down embodying a preferred mode of practicing this invention; i

FIG. 2 is a viewvupon an enlarged'scale :and shown j partially in section, illustrating a sleeve valve illustrated opposite two.v of the upper producing formations in the illustrations of FIGS; 1A and 1B\for the purpose of selec# tively establishing communication between the tubing and the producing formation; l l FIGS. 3A and 3B are a view on an enlarged scale,"in

'i vertical section, f of Vthe preferred embodiment ofV l the Another object is to provide .a well tool, for example:

' packer illustrated inFIGS. lAand 1B;

FIGSJ4A and 4B are views on ank enlarged scale showing the preferred hold-down tool'illustrated in FIGS. lA and 1B. A l 11 being perforated adjacent these formations as shown at 6a and 6b.

These producing formations are isolated from each other as well as from the bottom of the well and the ground surface by a series of packers lb, the details of which are shown in FIGS. 3A and 3B. Of course, it will be understood that more than two producing formations might be involved in a single well in which case the Y additional formations would be isolated similarly by. additional packers.

. ln the particular well illustrated, the bottom of the tubing is blanked off with a bull plug ll and formation 9 is the lowermost producing formation. Of course, the invention is equally applicable to wells in which the bottom of the tubing may communicate with the producing formation through a well screen or other suitable device. The tubing string, above the uppermost packer 1li is equipped with a hold-down indicated generally at l2.

Referring to the preferred embodiment ofthe packers, as shown at 10, they are of the type that require a support for the tubing below the packer to hold it against downward movement. In the illustration shown the bull plug at the lower end of the tubing bears directly against the bottom of the bore hole. However, it is contemplated that any other suitable means for supporting the tubing beneath the packers can be employed, and in fact, the lowermost packer of a series may be a` hook wall packer, which is conventional in the art. The hook wall packer can serve this purpose as well as to provide one of the series of packers.

' The bull plug il, or a conventional hook wall packer engaging the casing wall, if that alternative is used as lowest support for the tubing, bears all weight of( the tubing string not supported at the well head or supported by frictionalresistance of packers engaging the casing wall at lhigher locations.

The details of the construction of the packer lil are shown on an enlarged scale in FIGS. 3A and 3B. The tool may be considered as made up of inner and outer coaxially aligned telescoping parts. The outer telescoping part includes a number of components, as does the inner part. pling nipple i3 adapted to be secured to the lower end of a joint of tubing of a tubing string. This nipple is connected to a detent housing i4 provided at its lower end with an elongate wash pipe 14a. A sleeve l5 is connected between theV detent housing and a shoe i6 which makes the upper retainer 17 of the expansible packing assembly.

The inner part of the packer includes the lower coupling nipple 18 which secures the packer to a collar 19 of the tubing string immediately belowthe packer. The lower retaining ring 2d of the packing assembly abuts nipple 18 and surrounds the inner mandrel 2l about which the distortable packing material 22 is lodged. The packing material may be any of the materials presently used for The outer part has, at its upper end, a couup the lower end of the outer part. The shoe lo abuts this purpose. Several retainer ring packing assemblies may be mounted about mandrel 21. Sleeve 23, with a piston-like head 23a at its upper end, completes the inner part. This piston-like head fits between the wash pipe 14o and sleeve 15V and` is adapted to slide therein upon relative telescoping movement ofthe inner and outer parts. f

A number of annular seals, shown in the drawing, sealing between components that make up theinner and outer i parts have not been described because it is believedj'that their structure and function is obvious from the drawing.

lt will be noted that the inner and. outer telescoping parts, when in the position shown, with the packing means 22 contracted are adapted to be moved Vin telescoping relationship in a direction to radially expand the packing means by forcing the upper and lower retainer rings 17 and 2t), closer together. Telescoping parts to accomplish this function and result are known to the art, but some of the novelty here consists in providing a means to prevent premature expansion of the packer, which is releasable,

without altering the load on the packer or lower devices in the tubing. This means must, of course, be releasable by remote control from the surface, and in its preferred form is adapted to be released by a Wire line operation which is wholly independent of any manipulation ofthe tubing string.

In the form illustrated, this releasable means includes a fluid filled detent mechanism which may be released by manipulation of a wire line operated tool. The detent includes the sealed chamber 24 between the wash pipe 14a!V kand sleeve 1S, the lower end 'of which is sealed against the escape of iluid by chevron packing rings 25. The O-ring packing 26a seals between the piston-like head23a and the wash pipe 14a. It is seen that Vthe face end of head 23a confronts the downwardly facing shoulder 1412 so that iluid trapped in chamber 24 resists movement of the piston-like head 23a within the chamber. A hy# draulic fluid is preferred for chamber 24.

Means are provided to release the detent by venting the fluid from chamber 2.4. These include the spring pressed valve 26 and its registering seat 27. Of course, the spring and the pressure in chamber 24 will urge the valve member against the seat but this may be overcome by the pin il which presses against the tail piece on valve 26.v The in 28 is adapted to be lowered to open the valve whenV the sleeve 2 is lowered, due to a cam and follower con,-`

nection between the sleeve and the pin 28. This connection includes the cam part 3l) urged by the leaf spring 3l against Vthe cam notch 29aV formed in the periphery, of

sleeve 29. Cam part has a cam notch 30a engaging the follower end of pin 2S and it is obvious that when sleeve E is moved downwardly part 30is moved'radially to depress the pin Z8 and open valve 26. Set screw. 36

engages a vertical slot 2% in sleeve 29 to keep the sleeve properly aligned relative to the cam part 30. Chamber 24 is thus vented to the exterior of the packer through 'vent 28a.

To seal the opening, in which cam the interior passageway through the packer, is the function of seals 32 and 33. These can be dispensed with if the opening in which cam part 30 resides is closed to the exterior of the tool and chamber 24 is vented intothe interior of the packer. y notches 14d and 14e in which the snap ring 34 resides to hold the sleeve in a given position until sufficient force or impact is applied to it to move it either to raised o1- i lowered position. Upward movement of the sleeve is limited by the lower end of nipple 13 and downward.

Vmovement is limited by the inner taper 14C of the detent housing. The means for delivering the impact or moving force to the sleeve'for shifting it is illustrated diagram-'f ing movement of the inner and outer parts from the position shown in FIGS. 3A and 3B, in a direction` tobring l theupper and lower retainer rings of the packing assembly Y together, the packing means 22 is expanded radially to contact the well casing L6.V However, this vtelescoping movement is resisted by the fluid within chamber Zafgpref-V erably the chamber is nearly substantially filled with hydraulic fluid with only a relatively Vminor air space being left. ln fact, in low temperature installations the chamber v' 24 may be filled as nearly completely with hydraulic fluid I part so resides, from 'l The detent housing containsV Inasmuch as these shifting tools are well `known commercially available devices, Ya detailed discus-V Y sion of the tool will be dispensed with., It is believedV that the operation of the packer is apparent from the foregoing description., Upony telescop.

as is practically possible so that substantially no relative movement of the inner and outer parts is permitted until the fluid has been released. However, due to the expansion of the liquid upon an increase in temperature and the high tempertaures now prevalent in some localities in which such packers may be used, it is desirable to provide at least a small gas-filled space within the chamber to accommodate the expansion of the liquid without lbuilding up undue pressure within the chamber. Also, it is contemplated that chamber 24 may be filled with gas under pressure of a suflicient magnitude to prevent premature setting of the tool while the tubing string with the packers is being run into the well. Also, it is contemplated that a mechanical detent may be substituted for the fluid filled detent. The hydraulic detent is preferred because it does not require a high initial pressure and is very simple, yet is extremely rugged and is capable of transmitting very large loads between the innertand outer parts while preventing relative movement therebetween.

In making an installation where several packers are to be set, the packers are made up as a part of the tubing string as the tubing string is lowered into kthe well. They are, of course, properly spaced in accordance with the usual practice to locate the packers in the desired po-' sition within the well. To set the packers the wire line sleeve shifting tool 35 is lowered within the tubing string to a position suitable for first releasing the detent mechanism of the lowermost packer. With the particular tool referred to and illustrated in the Composite Catalog, the shifting tool is lowered beneath the lowermost packer and then raised until the upwardly facing dogs engage the lower shoulder of the sleeve. Suflcient Vforce is exerted either through a pull or through impact to shear the pin which is effective to hold the upwardly facing dogs expanded. This permits the upwardly facing dogs to be retracted by internal springs but simultaneously releases downwardly facing dogs so that they can be utilized. The tool is then pulled upwardly through the sleeve of the lowermost packer, which is permitted by the yielding action with which these dogs are mounted on Vthe tool. The 4tool may then be operated to shift the sleeve 29 downwardly.

The lower end of the tubing string is resting against the bottom of the hole but at this time the majority of the weight of the tubing string is held by the elevators at the top of the well. The weight of the tubing stringis known and the weight held by the elevators is indicated by a weight indicator at the ground surface. Sufficient amount of the weight is then allowed to be released to account for the weight of the tubing beneath the lowermost packer and an additional amount which is predetermined or selected to be the amount desired to be applied to the packer and effective to expand the packing means 22 to provide a seal. Inasmuch as the detent has been released, this slack-off of weight results in telescoping movement of the inner and outer parts of the packer to expand the packing material into engagement with thewall of the well casing. This expansion of the packing material takesV place immediately upon application of the weight to the outer part. After application of only a relatively small amount of the weight of the tubing to the tool the packing material is expanded into contact with the wall of the casing. The friction engagement of the packing ma terial with the well casing provides an anchor at this point for supporting additional load applied to the`device as additional weight is relieved atthe elevators.- The amount of load required to expand the packing until the friction between the packingand the casing is sufficient to support the load will depend upon the characteristics of the packing material, such as hardness, but with any given packer will be known within practical limits. This makes it possible to support on each packer a known weight of tubing or load within practical oil field tolerances or limits.

tubing beneath the lowermost packer is 1,000 .pounds lthe weight of the tubing string between the two packers.

to maintain the locking dogs retracted, which is released and the weight of tubing in addition to this that is required to collapse the packing material until it frictionally engages the well casing is 200 pounds, and it isv desired `to have approximately 10,000 pounds supported by the A lower packer to maintain the sealing engagement between -the packing material and the well casing, as well as with the mandrel 21, then approximately 11,200 pounds of lthe total load of the tubing string will be relieved at the ground surface.

ance or range of operation, and though in the Vspecification and claims it is indicated thatthe selected orpredetermined load is imposed on thepacker, it means within this wide tolerance. Usually a variation in the order of ten percent or even somewhat higher is permissible. t

After setting thef'first orV lowermost packer, the sleeve shifting tool is theniraised to the next higher packer and is operated to release lthe detent mechanism-of this packer. At this point the elevators are operatedto release an additional preselected amount of the weight ofthe tubing string. The release of the weight may be either before or after the release of the deten l In selecting the load .to be Limposed on the lower ofrtwo packers it must be borne in mind that the load cannot be less Vthan the weight of the string of tubing betweenthe two packers unless a suitable anchor is placed inthe string to engage the casing and thereby support the excess of It is seldom that this consideration is material, because the selected load on any packer usually, but not necessarily,

ranges from 7,000 to 10,000 pounds. 1,000 feet of two and one-half inch API tubing weighs. a little over 6,000 pounds, the exact weight depending upon the particular tubing employed. 2,00()l feet of two inch API tubing weighs in the neighborhood of 9,000 pounds. Packers n are seldom spaced far enough apart that the weight of intervening tubing will exceed 10,000 pounds.

The 'successively higher packers may be consecutively 'set in the manner described for-setting vthe lowermost packer'. If desired, a hold-down may be placed ink the tubing string above the uppermost packer or at any other place thatY it may be desired, which lwill Vbe useful for holding the load onfthe packers beneath it while permitting the tubing string thereabove to ber parted for the purpose of carrying out any desired oil well operation, or even production of oil or gas through the casing from a point in the well above the hold-down.

VA preferred Vhold-down is shown in FIGS. 4A and 4B, Y

which may also be set without manipulation ofthe tubing other-than to place the desired load on the device. In

vprinciple itis much the same as the packer previously described, except that the expansible means are locking dogs in place of the expansible packing means. The locking dogs are expanded to engage-the casing upon telescoping movement of the parts in onedirectiron. A releasable means is utilized to hold the telescoping parts in position by remote control without manipulation of 'the tubing in p any manner that would vaffect the load placed either on the hold-down or the packertherebelow. l v The tool comprises inner and outerV parts Vwhich are mounted for telescoping movement. The outer part consists of a detention housing 40 which may be connected at` its upper end to the lower end ofthe adjacent tubing string through the coupling 41. Preferably the coupling 41 has a square thread, easily disconnected, to permi't--back-off p of the coupling from the detent housing afterthe holdy down has been set'. The other end of the Adetent housing is formed with a wash pipe 40a and sleeve `42 is threaded to an intermediate section of the housing. The

sleeve and wash pipe provide the walls of the fluid charnber 43 and the chamber is completed in a manner to be hereinafter more fully described. The lower end of the sleeve ,42 carries a tapered shoe 44 at lthef terminus of vthe outer-part. I

Itis, of course, to be understood that practical oil field tolerances permit a substantial toler- The inner part is made up of lthe coupling 45 for engaging the upper portion of the adjacent tubing string. The mandrel 4o extends through the locking dogs 47 and the cooperating expanding tapered shoe 44. The locking dogs have a dovetailed, tongue and groove connection with the tapered shoe. The piston-like sleeve 43 is connected to the upper end of the mandrel and its upper head provides the abutting face confronting the down turned face at the other end of chamber 43 on the detent housing. The chevron packing 5S and O-rings59 and 59a comple'te the seal for the chamber. This head sti is adapted to move between the wash pipe ida and sleeve 42 to vary the volume of the chamber 013.

It will be noted that upon relative telescoping movement of the inner and outer parts from the position shown, in a direction 'to reduce the Avolume of chamber 43, the dogs 47 will be expanded by the tapered shoe 4d to engage the casing. This will, of course, anchor the device against upward movement due to forces generated below. Thus, if the tubing is disconnected from the device at coupling 41, the load on the lower packers will be maintained.

The chamber t3 and associated venting mechanism, provides a means for holding the device with the dogs 47 retracted, until chamber d3 has been vented. This venting mechanism is the same as that employed on the packers and includes the spring pressed valve Ai9 and seat 50. The pin 5l and the cam member 52. urged by leaf spring 53 into the cam notch on sleeve 54 complete the venting Y mechanism. The set screw 5S maintains alignment of the sleeve relative to cam member SZby engaging the vertical slot 54b therein. The sleeve is suitably sealed above and below the opening which houses earn member 52, and a snap ring 55 holds the sleeve in one of two selected positions until forced to the other position. The tapered sleeve 57 provides a stop for the upper end of the sleeve and also the interior tapers for cooperating with the dogs of the sleeve shifting tool.

It is believed that the operation of the hold-down will be apparent because it is identical to that described for the packer with the exception that theY function of the vhold-down is to merely hold the device against upward movement and not to provide a seal. It is set in precisely the same manner as previously described for the packer, but once set, the force from below acting upwardly main'- tains the dogs in engagement with the casing.V

' Opposite of the Vproducing formations in the tubing string is a sleeve valve 60 for selectively establishing communication between the formation and the interior of the tubing. The sleeve valve shown is conventional equipment and is illustrated at page 1967 of the Composite Catalog of Oil Field Equipment and Services for 1957, 22nd edition. Only a very brief description of the sleeve valve will bev given inasmuch as it is commercially available equipment,

FIG. 2 illustrates the interior vof the valve on an enlarged scale. lt consists of an outer housing 6l' which is coupled to adjacent lengths of tubing by

nipples

62 and 63. The housing has a series of perforations intermediate'its ends, passage through which is controlled by the sleeve 64 interiorly of the housing. Sleeve 64 has a series of perforations adapted to register with the perforations in the housing when the sleeve is in the position shown but lto be out of register when the sleeve is shifted to its lower position engaging the upper end of nipple 63.".675

O-ring seals carried by the sleeve on each side of thek perforations co-operate with the sleeve to shut orf flowwith the sleeve in lower position.

The size and number lof openings in the sleeve .may be i controlled to provide in effect a choke to control ythe volume of flow. The snap ring 65 is adapted to engage one of the two slots formed on the inner wall of housing 6l to retain the sleeve valve member in a selected position until it is shifted by a sleeve shifting tool. Y The sleeve shifting tool may be the same one that is employed for shifting the sleeves in the packersV and hold-down- With the arrangement shown in the drawings, one of the sleeve valves d@ may be opened while the others are closed so as to produce only from one of the producing formations at one time. In turn this valve may be closed and another sleeve valve opened to permitproduction from a different formation. With this arrangement the allowable from each formation may be produced through a single tubing string which is maintained, during periods of production, separated from the other formations.

connection with a producing well, it will be appreciated that the same arrangement of parts could be used as a* Y water injection well in which water could be injected either simultaneously to all of the formations, in which casethe sizing of the ports can control the quantity of injection into each formation, or into only onel of the formations at a time. Likewise, the system may be emi ployed for formation fracturing or other well operations.

It will be seen that the aims and objects of the invention have been accomplished. A packer and hold-down have been provided that may be set with a predetermined load placed thereon. The settingof a series of devices may be accomplished without manipulation of the tubing in a manner to disturb the load imposed on either theV device being set or of any'deviee therebelow.

inner and outer parts against relative movement to prevent premature setting of the packing means or the hold-p4 down dogs, may be released byremote control, as for example through the shifting of a sleeve by a wire line mechanism. The tubing string with its component parts may be assembled and installed in the well andthe lower` most packer first set and loaded with a predetermined portionof the weight of the tubing string thereabove.

The second packer may then be set and loaded With'faA predetermmed load, and this procedure followed through A hold-down may be set Y all the packers of the series. to maintain the load on the packers without disturbing the load previously placed on them. If desired, the tubing string above the hold-down may be .parted for-any desired purpose, and the packers will retain'their predetermined ,i

load. Y Y

A From the foregoing it will be seen that this invention 1s one well adapted to attain all ofthe ends and objects hereinabove set forth, together with other'advantages which are obvious and which are inherent to the ap-A paratus.' Y

It 'will' be understood that certain features and sub-VY combmatlons are of utility and may be employed withoutl` referenceto other features and subcombinations. This is contemplated by and is within the scope of the claims. i

As many possible embodiments may be made of the invention without departing from the scope thereof, itis to be understood that all matter herein setforth or shown in the accompanying drawings is to be interpretedas illustrative and not in a limiting sense.

' The invention having been described, what is claimed is: y

l. A well tool adapted for inclusion in a tubing string of a well comprising two coaxially aligned telescoping from the chamber, freeing the parts to move into telescopically collapsedy position expanding the expansible The arrangement 1s such that the detent for rnaintainingthel 2. The well tool ofclaim V1 wherein the expansible means includes dogs,V for engaging a well casing.

3. A well packer particularly adapted for use iny sealing between two strings of well pipe in. a series of such strings comprising two axially aligned telescoping parts connectible to separatev verticallyspaced strings of well pipe; radially expansible packing means disposed between opposing surfaces on said telescoping parts to be expanded outward upon movement of one yof said telescoping parts relative to the other of said parts; a releasable means including a sealed chamber having end walls which are surfaces of opposed shoulders on'said telescoping parts, 'a fluid in said chamber under pressure suiiicient to maintain the telescoping parts in telescopically expanded position, and means controllable from the surface for venting fluid from the chamber, freeing one of said telescopic parts to move into telescopically collapsed position rela tive to the other.

4. The combination of claim 3 wherein the means for releasing the uid from the chamber is controllable by a wire line operated tool.

5. A well tool adapted for inclusion in a tubing string of a well comprising two axially aligned telescoping parts connectible to separate sections in a tubing string; radially expansible means disposed to be expanded into engagement with a well casing upon movement of one of said parts into telescopically collapsed position with respect to the other; a releasable means including a sealed chamber having end walls which are surfaces of opposed shoulders upon said telescopic parts, a iluid in said chamber under pressure sufficient to maintain the telescopic parts in telescopically expanded position, `a vent 'through Va wall lof p said chamber, and a valve disposed to control ow of fluid from said chamber through said vent, and means for opening said valve, freeing said one telescopic part to move into telescopically collapsed position to expand the expansible means.

6. The well tool of claim 5 wherein the expansible means includes dogs for engaging a well casing.

7. A well packer particularly adapted for use between two strings of well pipe in a series of such strings comprising two coaxially aligned telescoping parts connectible to separate strings of well pipe; radially expansible packing means disposed to be expanded outward from the string upon telescopically collapsing movement of one of said parts relative tothe other; a releasable means disposed to retain the parts normally in telescopically exv panded position, said releasable means including a sealed chamber having end walls which are opposed shoulders on said coaxially aligned telescoping parts, a fluid in' said chamber under sutlicient pressure to support the parts in position to maintain the packing means in contracted state, a vent from said chamber, and means controlling ow through the vent including a valvev disposed in said vent for releasing fluid from the chamber, freeing the parts 9. A well tool'adapted to be connected in a tubing string of a well comprising inner and outer axially aligned telescoping parts connectible tojs'eparate sections ofya tubing string andhaving a passagewaythereth'rough; ,radially expansible means disposed to be expanded outwardr` '55 to move into telescopically collapsed position to expandfluid and freeing the parts to be moved toward telescopiycally collapsed` position to expand the expandible means.

10. The combination of claim 9, wherein the chamber is formedrby two annular concentric portions of one of the parts and an annular piston-like portion on the other of said parts. y

11. A well tool adapted to be connected in a tubing string of a well comprising inner and outer axially aligned parts mounted for telescopictmovement and connectible -to separate sections of a tubing string to provide a passageway through the tubing string and said parts; an ex pansible means mounted between opposingsu'rfa'ces von said parts to Vbe expanded radially outward upon telescopically collapsing movement ofthe parts; means` including confronting shoulders carried by the inner and outer parts in position to form a variable capacity chamber therebetween; a lluid inthe chamber providingva load-bearing connection between the parts to hold them lnormally in telescopically'expanded position; a vent communicating with. said chamber; a valve disposed to control uid flow through said vent; a membermovably mounted inthe passageway engageable by a tool passing therethrough and operably connectedjto the valve for opening vthe vent when engaged by said tool.

Y 12. The combination of claim llfwhereinsaid mem-r ber is a sleeve and a cam and follower connection isv v provided between the sleeve and the valve.

13. In a well tool adapted for inclusion in a tubing string of a well between adjacent upper and lower sections `of the'tubing string, vsaid well tool having a passageway for tiuid therethrough continuous with the bore of the tubing,rrneans providing relative `movement of the sections of tubingstring toward` and away from each other, expansible wall `engaging means, meansresponsive to relative movement of the sections ofl tubing string toward each other for expanding the wall engaging means into' wallkengaging position and responsive to ,relative movement of the sections of tubing string away from each other to retract the wall engaging means, and releasable means holding sections of tubing'string awayfrom each other with theexpansible wall engaging means in retracted posltion, that improvement which comprises a i pair of concentric tubular members axiallyreciprocable relative to ,each other, one of said pair of members being rigidly attached to an 'upper section of the'tubing string and the other of said pair ofmembers being rigidly attached to the adjacentlower section of theV tubing string;

a sealed chamber between opposed shoulders on the pair of tubular members; a fluid in said chamber normally underppressure suicient to hold said sectionsof `tubing l string away from each other retaining thefwallengaging means in retracted position, and means, operable from the surface. of the earth, for venting fluid frornzsaid chamber.

14. In combination, -a string of well casing and a e `string of well tubing therein; a plurality of well packers made up in the tubingstring having'openings therethrough providing'parts of the passageway through the tubing string; each of the well` packers?4 having two c'oaxiallyv aligned 'telescoping parts connectibleto separate sections upon telescopically collapsing movement of one of saidV parts relative to rthe other; means providing "a sealed,

variable capacitycliamber haVingf-end'walIsWhich are surfaces on confronting shoulders carried by s'aid 'innerand outer parts, a fluid 'iiigthe chamber providinga load-I' 5 sald vent; and means for opening-said valve, releasing ofthe tubingstring; a radially expansible packing means disposed Ato be expanded into s'ealingconifct with the casing` on movement'of one of saidftel'escoping parts into `telescop'ically collapsed relationship with the ,other part;

releasable means Aon eachvof the-packers including a hydraulic chamber and vavalve for releasing :duid therefromA disposed :to hold` the ,telescoping parts normally infteleseopicallyexpanded position; la trigger mechanism with a sensitive memberflocated withinfthe passageway operatively'connect'ed to said r'jelie'asable' means vto `release .thev same; and a selectively operable hold-down means connectedfinthe tubing string to form a part ythereof rand located above the packerspsaid hold-down means being operable to engage the casing and to hold the portion of 1 1 the tubing string beow the hold-down means against forces tending to move said tubing string in an upward direction, means releasaby connecting said hold-down means to the portion of the tubing thereabove to permit disconnection, said plurality of packers being consecu-` ReferencesCited in the file of this patent UNTED STATES PATENTS f Rhea June 27, -1916 Otis May 30,1933 Spang Dea 27, 1938 Reed Mayr, 1941 Boynton Apr.' 28, l1942 Edwards Dec'. `4, 1956 Lamberson et al. Feb. 4, 1958 Long Mar. 24, 1959V Smith Aug. 30, i960 Johnston May 30,1961

Claims

1. A WELL TOOL ADAPTED FOR INCLUSION IN A TUBING STRING OF A WELL COMPRISING TWO COAXIALLY ALIGNED TELESCOPING PARTS CONNECTIBLE TO SEPARATE ADJACENT SECTIONS OF A TUBING STRING; RADIALLY EXPANSIBLE MEANS DISPOSED TO BE EXPANDED INTO POSITION ENGAGING A WELL CASING UPON MOVEMENT OF ONE OF SAID TELESCOPING PARTS TOWARD TELESCOPICALLY COLLAPSED POSITION RELATIVE TO THE OTHER OF SAID PARTS; A RELEASABLE MEANS INCLUDING A SEALED CHAMBER BETWEEN OPPOSED SHOULDERS ON SAID PARTS, A FLUID IN SAID CHAMBER UNDER PRESSURE SUFFICIENT TO RETAIN SAID PARTS IN TELESCOPICALLY EXPANDED POSITION, AND A MEANS FOR RELEASING THE FLUID FROM THE CHAMBER, FREEING THE PARTS TO MOVE INTO TELESCOPICALLY COLLAPSED POSITION EXPANDING THE EXPANSIBLE MEANS.