US2695064A

US2695064A - Well packer apparatus

Info

Publication number: US2695064A
Application number: US107878A
Authority: US
Inventors: Thomas M Ragan; Martin B Conrad
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1949-08-01
Filing date: 1949-08-01
Publication date: 1954-11-23
Anticipated expiration: 1971-11-23

Description

Nov. 23, 1954 T M, RAGAN ET AL WELL PACKER APPARATUS 2 Sheets-Sheet l Filed Aug. l, 1949 Y B a 30 7 3.345%3 5 uw ,w 595 0 WQ i1/L 6 M 7g4 1 7 zw 7 7 s Nov. 23, 1954 T M, RAGAN ET Al.

WELL PACKER APPARATUS 2 Sheets-Sheet 2 Filed Aug. l, 1949 United States Patent WELL PACKER APPARATUS rl`hornas M. Ragan, Downey, and Martin B. Conrad, Huntington Parlr, Calif., assignors to linker @il Tools, Inc., Vernon, Calif., a corporation of California Appiieation August 1, i949, Serial No. 167,878

i9 Claims. (Cl. 16o-63) The present invention relates to well apparatus, and more particularly to well packers adapted to be set in well bores, as in conduits disposed in such bores.

it has been proposed to run a well packer in a casing string on a wire line and associated setting tool, the vpacker being set through use of a lluid or gaseous medium. After the packer has been completely set, the pressure of the iiuid medium is utilized to disconnect the setting tool from the packer and enable the former to be withdrawn from the well casing.

Heretofore, disconnection of the setting tool from the packer has occurred at relatively high fluid pressures, and has been accompanied by the imposition of high shock loads on the equipment. These shock loads are due to the ability of the high pressure fluid medium to expand suddenly and impart rapid movements to parts of the equipment, which then strike stationary abutments, after release of the setting tool from the packer.

Accordingly, it is an object of the present invention to enable high liuid pressures to be employed in setting a well packer, or in operating other subsurface tools, and yet avoid subjecting the equipment to sudden shocks or loads of a high order upon release of the setting tool or running-in string from the packer, or other subsurface tool.

Another object of the invention is to disconnect the setting tool from a well packer at an intermediate point in the setting operation, after which a greater setting force may be imposed on the packer to accomplish its anchoring against a well conduit to the desired extent.

Another object of the invention is to provide a well packer apparatus in which a fluid medium is utilized for setting the packer, and in which the fluid medium disconnects the setting tool or running-in string from the packer while the pressure is relatively small, the fluid medium then continuing to set the packer fully with an increasing and higher pressure. In this manner, sudden expansion of a high pressure fluid medium following release of a setting tool, or running-in string, is avoided.

A further object of the invention is to provide an improved well packer adapted to be anchored in packed on condition within a well casing or similar conduit.

Another object of the invention is to provide a well packer containing its own source of duid pressure for setting the packer in the well conduit, in which the fluid pressure effects detachment of the running-in string from the packer. More specifically, such detachment occurs before the liuid pressure has exerted its maximum force in setting the packer.

Yet a further object of the invention is to set a well packer by I'luid pressure, and avoid the necessity for overcoming the hydrostatic head of well fluid acting on the well packer.

Another object of the invention is to simplify considerably tools employed in the setting of a well packer, or other sub-surface well tool, in a well bore by iiuid pressure, the equipment being lowered in the well bore on F `re line, or corresponding running-in string.

Still another object of the invention is to make it easier and more economical to maintain and service equipment used in the setting or operation of a well packer, and other well tools, in well bores.

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 specifica;

4combined shear value than the tion. 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, with parts being shown in section, of a well packer apparatus disposed within a well casing, or other well conduit;

Fig. 2 is a longitudinal section, on an enlarged scale, through part of the apparatus disclosed in Fig. 1, the parts being shown in retracted position for lowering through the well casing;

Fig. 3 is an enlarged fragmentary longitudinal section through part of the tiring mechanism disclosed in Fig. 2;

Fig. 4 is a view similar to Fig. 2 disclosing the well packer partially set in the well casing;

Fig. 5 is a view similar to Fig. 2, showing all parts of the well packer expanded against the weil casing;

Fig. 6 is a partial section illustrating the disconnection of the setting tool from the well packer.

As disclosed in the drawings, the apparatus includes a well packer A detachably secured to a wire line B through a setting tool C which is essentially in the form of a firing mechanism. This setting tool may be attached to the wire line, for running the apparatus down through a well casing D, or other conduit, in the well bore, to the location at which the well packer is to be set.

The well packer A includes a generally tubular body lil, having a central chamber il therein, whose lower end is closed by a suitable threaded plug l2. An upper abutment i3 is threaderliy attached to the upper end of the body and engages an upper set of segmental slips lli, which are secured by shear screws 15 to an upper conical expander i6. This expander is attached to the upper end of a rubber or rubber-like packing sleeve i7, the lower end of which is secured to a lower conical expander 13. The lower expander is initially secured by shear screws i9 to a lower set of segmental slips Ztl, that engage the upper head end 2l of a cylinder 22 slidable along the exterior of the body lll.

The cooperable tapered surfaces 23 on the upper expander i6 and upper slips lll converge in an upward direction; so as to expand the slips ld radially outward upon upward movement of the upper expander i6 along the body itl. The external wickers or teeth Z4 on the upper slips face in an upward direction to grip the casing D and prevent upward movement of the well packer A within the casing.

ln a similar manner, the cooperable surfaces 2.5 on the lower expander 18 and slips 2li converge in a downward direction; so as to expand the lower slips outwardly against the casing upon their upward movement along the exterior of the lower expander. The wickers or teeth 26 on the lower slips 2@ face in a downward direction, to engage the casing D and prevent downward movementv of the packer A therewithin.

The upper shear screws l5 have a substantially lesser lower shear screws 19; so that an upward force exerted on all of these screws, in the manner described below, will first shear the upper screws l5 and move the upper expander lo within the upper slips i4, shifting the latter outwardly into en gagement with the well casing. Thereafter, the packing sleeve i7 is foreshortened and expanded outwardly into sealing engagement with the casing D, and the lower screws li then sheared to expand the lower slips 2d outwardly against the casing.

Such expansion of the packer parts occurs as a result of fluid pressure developed, preferably in a gradually increasing manner, within the body chamber il. This fluid pressure can pass outwardly of the body lil through a plurality of lower side ports 27 into a cylinder space 2,3 defined by the upper cylinder head 2l, a piston 29 mounted on the body below the ports 27, and a cylinder skirt 3l? slidable along the piston 29. The piston has a shoulder 3l resting upon a split ring 32 disposed within an external groove 33 in the body liti. The cylinder skirt 3l) is threadedly secured to the upper cylinder head 2l and is slidable along the periphery of the piston 29, .extending on opposite sides of the piston. At its lower end, the cylinder sleeve 30 is secured to a lower head 34 slidable along a depending body extension 10a.

Leakage around the upper cylinder head 21 is prevented by one or more side seals 35 carried by the head and slidably engaging the periphery of the body leakage between the head 21 and the cylinder skirt 30 is prevented by a thread seal 36; leakage in a downward direction between the body 10 and piston 29 is prevented by an inner side seal 37 in the piston engaging the periphery of the body; whereas the piston also carries one or more piston rings 38 slidably engaging the inner surface of the cylindrical skirt 30. The lower head 34 also is provided with a plurality of side seals 39 slidably engaging the body extension 10a.

The upper cylinder head 21 is coupled initially to the lower slips 20 by an external head flange 40 fitting within a companion internal groove 41 formed in the slips. When the slips 20 are in retracted position, the cylinder head 21 may be in abutting relation with the upper end of the stationary piston 29. When in this position, the cylinder 22 is prevented from moving upwardly by one or more shear screws 42 attaching the lower head 34 to the body extension 10a. This lower head may be protected by a lower abutment 43 threaded on the lower end si the extension and disposed adjacent the cylinder head The body chamber 11 is sealed against ingress of the well fluid and originally contains air at atmospheric pressure. This is also true of the annular space 44 between the body extension 10a and the cylinder skirt 30, which is sealed against entry of the well fluid, and which initially contains air at atmospheric pressure. Air is confined in the last-mentioned annular space 44 to avoid the necessity for the pressure built up in the body 10 and in the cylinder space 28 to overcome the hydrostatic head of fluid in the well casing D during setting of the packer A.

The iiuid under pressure may be provided through use of a relatively slow burning combustible charge. This charge may be provided by a railroad are or fusee 45, and may be of the general type described in the application of Reuben C. Baker et al., Serial No. 1845, iiled January l2, 1948, for Gas Operated Well Apparatus, now Patent No. 2,640,547. Since it is desired to set the well packer upon the occurrence of a predetermined sequence of operations, the pressure in the body chamber 11, which may be transmitted through the ports 27 to the cylinder space 28, should be built up in a comparatively gradual manner.

The combustible charge 45 may be disposed within a tubular container 46 open at its upper end, and having a ange 47 resting upon a shoulder 48 at the upper portion of the body. The upper end of the combustible charge 45 may be ignited. as through firing of a blank cartridge 49 contained within a gun barrel 50 disposed within an upper bore 51 in the body 10. After the combustible charge is ignited, it burns, since it contains its own source of oxygen, and creates a gas which graduallv increases in pressure. This gas passes down into the body chamber 11 and out through the ports 27 into the cylinder space 28. exerting an upward force on the upper cylinder head 21 and a reactive downward force on the piston 29. which is transmitted to the packer body 10 through the ring 32. As evolution of gas from the power charge 45 increases, its pressure also increases until the shear value of the screws 42 holding the lower cylinder head 34 to the body 10a is exceeded. and also the shear value of the upper screws securing the upper slips 14 to the upper expander 16. When these screws are disrupted, the cylinder 22, lower slips 20, lower expander 18, packing sleeve 17 and upper expander 16 are moved upwardly along the body as a unit, which shifts the upper expander 16 within the upper slips 14, and forces them laterally outward into anchoring engagement with the wall of the well casing D (see Fig. 4).

As the pressure continues to increase, the cylinder 22, lower slips and lower expander 18 are moved as a unit toward the upper expander 16, foreshortening the packing sleeve 17 and expanding it radially outward into sealing engagement with the casing (Fig. 4). Further increase of the gas pressure within the chamber 11 and cylinder space 2S will eventually overcome the shear strength of the lower screws 19, disrupting them and shifting the lower slips 20 upwardly over the lower expander 18 and into anchoring engagement with the well casing D.

The iiuid pressure continues to increase, which further anchors the

slips

14, 20 against the casing and expands the packing sleeve 17 more securely between the well packer body 10 and the well casing D.

When the slips 14, 20 and packing 17 have been expanded into iirm anchoring condition with the well casing, the entire well packer A is prevented from moving in either direction. Any tendency for the packer body 10 to move downwardly is resisted by engagement of the upper abutment ring 13 with the upper slips 14, which transmit the downward force through the upper expander 16, packing sleeve 17, lower expander 18 and lower slips 20 to the well casing D. Any tendency for the packer body 10 to move in an upward direction is prevented by a lock ring 49a disposed in the upper expander 16. This lock ring 49a is a longitudinally split, inherently contractible member adapted to grip the periphery of the body 10 irmly. If desired, such gripping action may be enhanced by slightly roughening the upper periphery portion of the body. The exterior of the ring 49a is provided with a plurality of tapered surfaces 50a engageable with companion tapered surfaces 51a in the expander 16. These tapered surfaces converge in an upward direction.

Any tendency for the body 10 to move upwardly causes it to carry the ring 49a with it in an upward direction. The tapered ring surfaces 50a engage the companion tapered or cam surfaces 51a in the expander, which forces the ring more firmly into the body and effectively couples it thereto. The upward thrust is transmitted from the body 10, through the ring 49a, to the upper expander 16, from where it passes to the upper slips 14 and to the casing string D.

To insure proper anchoring of the well packer A in packed-0E condition in the well casing D, comparatively high pressures may be necessary. As an example, pressures of the order of 5000 or 6000 p. s. i. may be developed in the packer body 10 to etiect full setting of the well packer. As indicated above, such force acts on the yupper expander head 21 in an upward direction, and acts on the piston 29, to urge the body in a downward direction, thus etectively expanding and holding all of the parts in an outward position against the casing.

It is desired to lower the well packer A in the well casing D by means of a wire line B and an associated setting tool C, and to automatically effect release of this setting tool. Such release is accomplished by the gas pressure developed within the body chamber 11. It is preferred that the release occur after all of the

packer parts

14, 17, 20 have been expanded against the casing, but before a comparatively high pressure has been developed within the body chamber 11 and cylinder space 2 One form of arrangement for accomplishing these purposes is disclosed in the drawings. The wire line B is secured by babbitt metal (not shown), or in any other suitable manner, within a wire line socket 52, which is threadedly attached to the upper end of a sinker bar 53. The lower end of this sinker bar is threaded onto the upper end of a gun body 54, which has an extension 55 threaded into its main portion and piloted within a sub or head 56 threaded into the upper body bore 51. The setting tool C is releasably secured to the well packer A by one or more shear screws 57 threaded into the upper head 56 and into the gun body extension 55.

The body bore 51 contains the gun barrel 50 in which the blank cartridge 49 is disposed in a central position. A thin flexible metallic disc 58` such as a copper disc, is disposed across the upper end of the gun barrel and cartridge. being clamped thereagainst by a breechblock or cap 59 that has an extension 60 proiecting upwardly through the sub 56 into engagement with the gun body extension 55. Leakage around the exterior of the gun barrel 50 is prevented by one or more side seals 61 in the barrel engaging the wall of the body bore 51, whereas leakage through the bore 62 of the barrel and around the cartridge 49 is prevented by a gasket 63 in the barrel engaging the lower surface of the flexible disc 53, and by another gasket 64 in the breechblock 59 engaging the upper surface of the disc 58.

When the shear screw 57 is in position, holding the setting tool C assembled to the well packer A, the gun barrel 50 and breechblock 59 are disposed in a lower `the gun body d, the lower end of maintain the latch lingers 73 position, with an upper shoulder 65 of the breechblock spaced from the lower end 66 of the sub by a Vsubstatitial amount. The distance across this space is greater than the diameter of the shear screw 57 holding the gun body extension 55 to the sub 56, in order to permit upward movement of the gun barrel Si? and breechblock 59 to shear the screw 57 and disconnect the setting tool C from the well packer A, as explained hereinafter.

The cartridge 49 may be tired by any suitable means. Mechanical firing is provided for, as disclosed in the drawings. The cartridge is tired by a firing pin 67 disposed centrally within the gun body 54, and having its tapered end 68 adapted to move downwardly, for the purpose of striking and indenting the ilexible disc 58 and cartridge 49. The pin is urged in the downward direction by a compressed helical spring 69 disposed within the spring engaging a ange 7d formed on the firing pin 67, and its upper end engaging a seat 7l formed on the body. The pin shaft 72 has a pair of downwardly facing wings or hooks 73 adapted to be engaged by the latch fingers 74, depending from latch levers 7S disposed within an elongate, transverse slot 76 in the gun body 54. The latch levers 75 are mounted on pins 77, and have upper arms 78 which are urged in an outward direction by an expansible spring 79 received within recesses 8b in the arms, in order to 7d under the tiring pin hooks The latch lever arms 78 have upper faces 8l inclined in an upward and inward direction, and adapted to be engaged by a friction drag device S2, in order to swing the arms 78 inwardly and the latch ngers 74 outwardly, to release the tiring pin 67. The drag device includes a lower collar 83 slidable on the sinker bar 53, to which the lower ends of outwardly bowed springs 84 are suitably secured, as by use of the screws S5.' The upper ends of the springs are similarly secured to an upper collar 86 slidable on the wire line socket 52 and sinker bar 53. The springs 84 frictionally engage the wall of the casing D and resist longitudinal movement of the drag device 82 therewithin.' Upward movement of the drag device 82 along the sinker bar 53 is limited by engagement of the lower collar 83 with a split stop ring 87 disposed within a circumferential groove S3 in the sinker bar.

The tool is run in the well bore, with the parts occupying the positions disclosed in Figs. l and 2. The latch levers 75 hold the firing pin 67 in its elevated position above the flexible disc 58 and cartridge 49, the drag device 82 tending to move upwardly along the sinker bar 5.3 and remaining out of engagement with the latch lever arms 7S. When the location has been reached in the well bore at which the packer A is to be set, the wire line B is elevated, which elevates all parts of the apparatus with the exception of the drag device 82, `since the latter is prevented from moving upwardly by the frictional engagement of its springs 84 against the wall of the casing D. Elevation continues until the lever arms 78 are pulled within the lower drag collar 33, which forces these arms inwardly against the action of the expander spring 79 and releases the latch fingers 7d from the tiring nin hoo-ks '73. Such release altows theV cornpressed springs 69 to rapidly shift lthe pin 67 downwardly to strike its point 68 against Vthe tiexible disc 5% and cartridge 49. igniting the latter and initiating the cornbustion of the combustible charge 45 within the bodv chamber 11. Downward movement of the tiring pin 67 is limited by engagement of a transverse rod 90 on the tiring pin with a stop pin 9i extending across the gun body slot 76.

As pressure is gradually built up in the body chamber lll, the slips 14. 20 and packing 17 are expanded against the well casing D, in the manner described above. After such expansion has occurred, and while the pressure in the body chamber 11 and cylinder 28 is still at a relatively low value. it is desired to release the setting tool C from the well packer A.

It is to be noted that the gun barrel Si) is held in its lower position, resting upon the body shoulder 92, by the shear screw or screws 57 securing the gun body 54 to the well packer A. As the pressure in the body chamber lll increases, it acts upwardly over the entire across-sectional area of the gun barrel 5b, tending to elevate the latter within the packer body. Such elevating movement is resisted by engagement of the breecholock 59, 60 with the cartridge 49 can be employed.

the lower end of the gun body extension 55. However, when a predetermined pressure is developed in the body chamber, the shear value of the screws 57 is exceeded by the Vforce exerted thereon by the gun barrel 50, causing their disruption and automatic release of the setting tool C from the well packer A, as disclosed in Fig. 6. Such disruption can occur, since the gun barrel Si) and the breechblock 59, 6) atttached thereto can move upwardly within the packer body until the breechblock shoulder 65 engages the lower end 66 of the sub 56. This movement is of a relatively slight extent. When the shear screws 57 are disrupted, since the gun barrel can only movea slight distance, the gun barrel 50 can only strike a comparatively light impact blow against the sub 56. The extent of this blow is further minimized, since the shear screws 57 are designed to be disrupted at a relatively low pressure in the packer body chamber 11. As an example, the pressure may be of the order of 500 p. s. i. This pressure is sufficient to expand the slips 11i, 2t) and packing 17 against the casing D, but with a lesser pressure than is desired to fully and rmly anchor the well packer against the well casing.

After the setting tool C has been released from the well packer, the combustible charge 4S continues to generate gas at a continuously increasing pressure, which acts upon the cylinder head 2l and the body piston 29 to engage the

slips

14, 20 and packing 17 more rmly with the well casing. This force will continue to increase until the maximum pressure that can be developed by the combustible charge has been reached. As an example, this pressure may be of the order of 6000 p. s. i.

It is apparent that release of the setting tool C from the well packer A during an intermediate and preferably relatively low state in the pressure development subjects the equipment to a comparatively small impact blow, and does not result in any damage whatsoever to the equipment. This blow is much less than would occur were the packer A first set with the maT-:irnum force required and the setting tool C then released. Nevertheless, the desired maximum setting torce is imposed upon the well packer, in the absence of its connection to the setting tool.

It has been stated that the cylinder space 44 belowt the piston 29 initially contains air at atmospheric pressure, and that well fluid is prevented from entering this cylinder space. This arrangement is provided so that the hydrostatic head of duid acting on the annular cylinder 22 in both an upward and downward direction is counterbalanced. It is to be noted that the hydrostatic head will act upwardly over the area of the lower cylinder head 34, and that it will also act downwardly over the area of the upper cylinder head 2l. Since these areas can be made equal, the hydrostatic head has no influence in resisting upward movement of the cylinder 22 along the packer body it). Accordingly, it is not necessary to develop any pressure in the packer chamber l1 to overcome the hydrostatic head. All of the pressure is .available for use in setting the well tool.

in view of the fact that the combustible charge 45 is disposed within the well packer itself, which is also true of the gun barrel Si) and cartridge 49, the setting tool C may be relatively simple. As disclosed, it merely consists of a mechanically releasable and actuated tiring pin 67. Of course, any other suitable manner of firing The cartridge can be of the type containing a heating larnent and disposed in an electric circuit in series with a wire line E containing a conductive core. Upon completion of the circuit, the cartridge is discharged and combustion of the charge 45 in the packer body it? initiated.

Since the setting tool C is relatively simple, it is easy to maintain. After each run, and following withdrawal of the setting tool from the well bore, it is a simple matter to clean its parts and place the setting tool in condition for use in coniunction with another well packer, or another subsurface well tool.

The inventors claim:

l. ln subsurface well apparatus: a tool to be disposed in a well bore; a suspension device connectible to a running-in string; means detachably securing said device to said tool to enable said tool to be lowered in the well bore by the running-in string; said tool having actuatable means to be operated in the well bore; operating means within said tool for operating said actuatable means; means for releasing said operating means for applica-l tion to said actuatable means; and means actuated by said operating means to release said detachable means to disconnect said device from said tool.

2. In subsurface well apparatus: a tool to be disposed in a well bore; a suspension device connectible to a running-in string; means detachably securing said device to said tool to enable said tool to be lowered in the well bore by the running-in string; said tool having actuatable means to be operated in the well bore; means providing a source of uid pressure within said tool for operating said actuatable means; means for releasing said iluid pressure for application to said actuatable means; and means subjected to and actuated by the uid pressure in the tool to release said detachable means.

3. In subsurface well apparatus: a tool to be disposed in a well bore; means detachably securing said tool to a running-in string; means providing a source of fluid pressure within said tool; means for releasing said fluid pressure; and means subject to and actuated by the uid pressure in the tool to release said detachable means.

4. In subsurface well apparatus: a tool to be disposed in a well bore; a suspension device connectible to a running-in string; a breakable connection securing said device to said tool; said tool having actuatable means to be operated in the well bore; means providing a source of uid pressure within said tool for operating said actuatable means; means for releasing said fluid pressure for application to said actuatable means; and means subjected to and actuated by the uid pressure in the tool to break said connection.

5. In subsurface well apparatus: a tool to be disposed in a well bore; a suspension device connectible to a running-in string; a breakable connection securing said device to said tool; said tool having actuatable means to be operated in the well bore; means providing a source of uid pressure within said tool for operating said actuatable means; means for releasing said uid pressure for application to said actuatable means; and means subiected to and actuated by the fluid pressure in the tool to break said connection, said breakable connection being made of a material and of dimensions to break upon being subjected to a substantially lesser fluid pressure force than is finally developed in said tool.

6. In subsurface well apparatus: a tool to be disposed in a well bore; a suspension device connectible to a running-in string; means detachably securing said device to said tool; a combustible charge within said tool; said tool having actuatable means to be operated in the well bore; means for initiating combustion of said charge for operating said actuatable means; and means subjected to and actuated by the gas pressure developed by said charge in the tool to release said detachable means.

7. In subsurface well apparatus: a body; normally retracted expansible means on said body; means including a detachable connection for securing said body to a running-in string for lowering said body in a well bore; means on said body for expanding said normally retracted means laterally outward; operating means within said body for actuating said expanding means; and means actuated by said operating means to release said detachable means.

8. In subsurface well apparatus: a body; normally retracted means on said body; means including a detachable connection for securing said body to a running-in string for lowering said body in a well bore; uid pressure operated means for expanding said normally retracted means laterally outward; means providing a source of uid pressure within said body for actuating said fluid pressure operated means; and means subjected to and actuated by the fluid pressure within said body to release said detachable means.

9. In subsurface well apparatus: a body; normally retracted means on said body; means including a detachable connection for securing said body to a running-in string for lowering said body in a well bore; fluid pres sure operated means for expanding said normally retracted means laterally outward; a combustible charge within said body; means for initiating combustion of said charge to produce gas under pressure for action on said fluid pressure operated means; and fluid pressure means subject to and actuated by the gas under pressure produced by said charge to release said detachable connection.

l0. In subsurface well apparatus: a body; normally retracted means on said body; means including a detachable connection for securlng said body to a running-in string for lowering said body in a well bore; fluid pressure operated means for expanding said normally retracted means laterally outward; a combustible charge within said body; means for initiating combustion of said charge to produce gas under pressure for action on said fluid pressure operated means; and uid pressure means subject to and actuated by the gas under pressure produced by said charge for releasing said detachable connection; said detachable connection being designed and arranged for release upon being subjected to a substantially lesser gas pressure force than is finally developed in said body.

1l. In subsurface well apparatus: a body; normally retracted means on said body; means including a detachable connection for securing said body to a running-in string for lowering said body in a well bore; fluid pressure operated means operatively engageable with said normally retracted means for expanding said normally retracted means laterally outward; a combustible charge within said body; a shiftable gun barrel operatively associated with said body and with said detachable connection; said uid pressure operated means and gun barrel being in fluid communication with the interior of said body; a cartridge in said barrel; means for firing said cartridge to initiate combustion of said charge to produce gas under pressure for action on said Huid pressure operated means and for action upon said gun barrel to shift said gun barrel to a position releasing said detachable connection.

l2. In a well tool: a body; normally retracted means on said body; an annular piston secured to the exterior of said body; an imperforate annular cylinder engageable with said normally retracted means and slidable along said piston and also along the exterior of said body on both sides of said piston in leakproof relation to said piston and body to prevent entry of uid into the cylinder on one side of the piston, said body having a port on the other side of said piston through which fluid under pressure within said body can be directed into said cylinder.

13. In a well tool: a body; normally retracted means on said body; an annular piston secured to the exterior of said body; an imperforate annular cylinder engageable with said normally retracted means and slidable along said piston and also along the exterior of said body on both sides of said piston in leakproof relation to said piston and body to prevent entry of iluid into the cylinder on one side of the piston, said body having a port on the other side of said piston through which fluid under pressure within said body can be directed into said cylinder; the external cross-sectional areas of said cylinder on opposite sides of said piston between said body and the periphery of said cylinder, over which fluid in the wlll bore can act, being substantially equal to each ot er.

14. In a well tool: a body; normally retracted means on said body; an annular piston secured to said body; an annular cylinder engageable with said normally retracted means for expanding said normally retracted means laterally outward, said cylinder including cylinder heads on opposite sides of said piston slidable along said body and an imperforate cylinder skirt secured to said heads and slidable along said piston; sealing means for preventing fluid leakage between said heads and body and between said skirt and piston; said body having a port through which fluid under pressure in said body can be directed into said cylinder between said piston and one of said heads; the space between said piston and the other of said heads being devoid of liquid.

15. In a well tool: a body; slips disposed around said body; expander means for shifting said slips laterally outward; an annular piston secured to said body; an annular cylinder for shifting said slips and expander longitudinally relative to each other, said cylinder including cylinder heads on opposite sides of said piston slidable along said body and an imperforate cylinder skirt secured to said heads and slidable along said piston; sealing means for preventing fluid leakage between said heads and body and also between said skirt and piston; said body having a port through which uid under pressure within said body can be directed into said cylinder between said piston and one of said heads; the space between said piston and the other of said heads being devoid of liquid.

16. In a well tool: a body; an upper set of slips around said body; an upper expander engageable with said slips for shifting said slips laterally outward; a lower set of slips around said body; a lower expander engageable with said lower slips for shifting said lower slips laterally outward; packing means surrounding said body and engageable with said upper and lower expanders; an annular piston mounted on said body; an annular cylinder engageable with one of said sets of slips for shifting said one set of slips along its cooperable expander, said cylinder including piston slidable along said body and an imperforate cylinder skirt secured to said heads and slidable along said piston; sealing means for preventing fluid leakage between said heads and body and also between said skirt and piston; said body having a port through which fluid under pressure within said body can be directed into said cylinder between said piston and one of said heads; the space between said piston and the other of said heads being devoid of liquid.

17. In a well tool: a body; an upper set of slips around said body; an upper expander engageable with said slips for shifting said slips laterally outward; a lower set of slips around said body; a lower expander engageable with said lower slips for shifting said lower slips laterally outward; packing means surrounding said body and engageable with said upper and lower expanders; an annular piston mounted on said body; an annular cylinder including upper and lower cylinder heads on opposite sides of said piston that are slidable along said body and an imperforate cylinder skirt secured to said heads and slidable along said piston, said upper head being engageable with said lower slips; frangible means securing said upper slips to said upper expander; frangible means securing said lower slips to said lower expander and having a higher shear value than said other frangible means; said body having a port through which lluid under pressure wit in said body can be directed into the cylinder space between said piston and said upper head to urge said cylinder upwardly along said body; the space between the piston and said lower head being conheads on opposite sides of said fined against ingress of well fluid devoid of liquid. Y

18. In subsurface well apparatus: a tool to be disposed in a well bore; a suspension device connectible to a running-in string; means detachably securing said device to said tool; said tool having actuatable means to be operated in the well bore; a source of energy within said tool capable of developing a gradually increasing pressure to operate said actuatable means while said pressure is increasing; means for releasing said energy for application to said actuatable means; and means subjected to and actuated by the pressure developed by said source of energy in said tool to release said detachable means before said pressure reaches its maximum value.

19. ln subsurface well apparatus: a body; normally retracted means on said body; means including a detachable connection for securing said body to a running-in string for lowering said body in a well bore; fluid pressure operated means for expanding said normally retracted means laterally outward; a source of energy within said body capable of developing a gradually increasing pressure to actuate said fluid pressure operated means while said pressure is increasing; and means subjected to and actuated by the pressure developed by said source of energy in said body to release said detachable means before said pressure reaches its maximum value.

and being substantially References Cited in the lle of this patent UNITED STATES PATENTS Number Name Date 2,189,697 Baker Feb. 6, 1940 2,189,937 Broyles Feb. 13, 1940 2,194,331 Strom Mar. 19, 1940 2,233,930 Witt Mar. 4, 1941 2,275,935 Baker Mar. 10, 1942 2,330,265 Burt Sept. 28, 1943 2,373,006 Baker Apr. 3, 1945 2,467,801 Baker Apr. 19, 1949