US3252516A

US3252516A - Hydraulically operated well packer apparatus

Info

Publication number: US3252516A
Application number: US235258A
Authority: US
Inventors: Leutwyler Kurt
Original assignee: Baker Oil Tools Inc
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 1962-11-05
Filing date: 1962-11-05
Publication date: 1966-05-24
Anticipated expiration: 1983-05-24
Also published as: GB1019250A; DE1242169B; FR1379843A

Description

May 24, 1966 K. LEUTWYLER 3,252,516

HYDRAULICALLY OPERATED WELL PACKER APPARATUS 9 Sheets-Sheet 1 Filed Nov. 5, 1962 INVENTOR. K027 LEurn fl 2 flrroeusYs.

May 24, 1966 K. LEUTWYLER 3,252,516

HYDRAULICALLY OPERATED WELL PACKER APPARATUS 9 Sheets-Sheet 2 Filed NOV. 5, 1962 M60 3Q: FI Go 3 0 60 36' 1 0.

INVENTOR.

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May 24, 1966 K. LEUTWYLER 3,252,516

HYDRAULICALLY OPERATED WELL PACKER APPARATUS Filed Nov. 5, 1962 9 Sheets-Sheet 3 E0 4 56 Fiat 50 INVENTOR.

K097 LEUTWYL EQ May 24, 1966 K. LEUTWYLER HYDRAULICALLY OPERATED WELL PACKER APPARATUS Filed Nov. 5, 1962 9 Sheets-Sheet 4 INVENTOR.

bi Kuer [EurwmEe BY fir roeusys.

May 24, 1966 K. LEUTWYLER 3,252,516

HYDRAULICALLY OPERATED WELL PACKER APPARATUS 9 Sheets-Sheet 5 Filed Nov. 5, 1962 INVENTOR. Ever Laura/meg flrraezvsys.

y 1966 K. LEUTWYLER 3,252,516

HYDRAULICALLY OPERATED WELL PACKER APPARATUS 9 Sheets-Sheet 7 Filed NOV. 5, 1962 INVENTOR. K1187 LEUTWyLEIZ y 1966 K. LEUTWYLER 3,252,516

HYDRAULICALLY OPERATED WELL PACKER APPARATUS Filed Nov. 5, 1962 9 Sheets-Sheet 8 a2 8IG. I: 6U 67 I at? i\ M 11$ 85 as 4 a4 1% ass F T WE 88 35 {I 87 89 i i 90 5 INVENTOR. E027 LEurwyL 52 14 rraRA/EYS.

United States Patent 0 M Filed Nov. 5, 1962, Ser. No. 235,258 25 Claims. Cl. 166-120) The present invention relates to subsurface well bore equipment, and more particularly to well packer apparatus adapted to to be set in well bores.

Some packers are set hydraulically in well bores and may be maintained in set condition by the continuous application of hydraulic pressure thereto. If the pressure in the well bore applied to a packer is relieved or diminishes below a minimum setting value, release of the packer from the wall of the wellbore occurs. The trapping of hydraulic pressure in the well packer can make its continued set condition independent of subsequent pressure in the well bore, but such trapped pressure diminishes or becomes a nullity in the event of subsequent partial extrusion or cold flow of the packing material (forming the sealing portion of the packer against the wall of the well bore) and around adjacent well packer parts, resulting in undesired release of the packer from the well bore wall.

Accordingly, it is an object of the present invention to provide a well packer set by fluid or hydraulic pressure, in which ample fluid pressure is constantly available in the packer to maintain it in packed-oil condition in the well bore despite diminution of the pressure in the well bore below the minimum packer setting pressure, and despite subsequent partial extrusion or cold flow of the packing material of the well packer.

Another object of the invention is to provide a well packer adapted to be set in the well bore by fluid pressure, in which the fluid pressure can be trapped or confined in the packer to insure its maintenance in set condition despite an excessive diminution of the well bore pressure, and in which the pressure can be easily relieved in the event it is desired to release the packer from the wall of the well bore.

A further object of the invention is to provide a well packer set in a well bore by hydraulic or fluid pressure applied to a fluid operated actuator portion of the packer and maintained in set condition by trapping fluid pressure therewithin, which the packer is releasable from the wall of the well bore by substantially simultaneously communicating the high and low pressure sides of the fluid operated actuator to essentially the same pressure source in the well bore, as, for example, simultaneously bleeding or venting the high and low pressure sides of the actuator.

An additional object of the invention is to provide a well packer having an improved mechanism for preventing premature setting of the packer while it is being run in the well bore.

Yet a further object of the invention is to provide a well packer adapted to be set in a well bore by fluid pressure, in which release of the well packer is efifected by equalizing the pressure across its fluid pressure operated actuator, and in which inadvertent or premature pressure equalizing is prevented.

Another object of the invention is to provide a well packer adapted to be set in the well bore by fluid pressure, in which the packer is capable of adjustment for setting under one pressure condition or under another condition. The packer may be adjusted for setting when a tripping device is moved through it, or it may be adjusted or converted so that the tripping device merely conditions it for subsequent setting.

3,252,516 Patented May 24, 1966 Yet another object of the invention is to provide well packers capable'of being run in tandem in a well bore and set therein, the order of setting of the packers being preselected so that one can be set in advance of another, or some or all can be set simultaneously.

Still a further object of the invention is to provide a subsurface well tool having parts initially secured together by a frangible device, in which torque required to shear the frangible device is much greater than the corresponding longitudinal force required to shear the same device.

Another object of the invention is to provide a subsurface well tool having parts releasably connected together, as by means of a frangible connection, in which the parts are released from one another, or the frangible connection disrupted, by the application of a much lesser force than the strength of the connection, such lesser force being transmitted-to the connection through a mechanical advantage or force multiplying device.

A further object of the invention is to provide a Well packer or packers having parallel passages therethrough for communication with parallel tubular strings extending to the top of the well bore, which packer or packers are capable of accomplishing the aforementioned objectives.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a side elevational view of a well packer embodying the invention, with its parts in retracted position;

FIGS. 2a and 2b together constitute a longitudinal section through the well packer disclosed in FIG. 1, with the parts in their initial position for lowering in a well casing, or similar conduit string, disposed in the well bore, FIG. 2b being a lower continuation of FIG. 2a;

FIGS. 3a, 3b, 3c and 3d together constitute a side elevational view, with parts broken away, of a tandem packer arrangement disposed in a well bore for conducting production from a plurality of zones through parallel tubular strings to the top of the well bore, FIGS. 3b, 3c and 3d being lower continuations of FIGS. 3a, 3b and 3c, respectively;

FIG. 4 is an enlarged longitudinal section through the hydraulic actuator portion of the well packer with its parts in their initial conditon;

FIG. 5 is an enlarged cross-section taken along the line 55 on FIG. 4;

FIG. 6 is an enlarged cross-section taken along the line 6-6 on FIG. 4;

FIG. 7 is an enlarged cross-section taken along the line 77 on FIG. 4;

FIG. 8 is an enlarged longitudinal section through a hydraulic control unit embodied in the well packer, adjusted for. one operating condition;

FIG. 9 is a view similar to FIG. 8 disclosing the control unit adjusted or disposed in another operating condition;

FIG. 10 is a view of the lower portion of FIG. 9 illustrating its check valve in an open condition;

FIGS. lla and 11b are longitudinal sections, on an enlarged scale, of the apparatus illustrated in FIGS. 2a and 2b, showing the well packer anchored in packed-off condition in the well casing, FIG. llb being a lower continuation of FIG. 11a;

FIGS. 12a and 12b are enlarged fragmentary, longitudinal sections illustrating the hydraulic actuator in its position after having effected expansion of well packer parts outwardly against the well casing, FIG. 12b being a lower continuation of FIG. 12a;

FIGS. 13a, 13b and 130 are enlarged longitudinal sections, with parts shown in :side elevation, of one side of the parallel packer with the parts shifted to a packer releasing condition, FIGS. 13b and 130 being lower continuations of FIGS. 13a and 1312, respectively;

FIG. 14 is a fragmentary cross-section, on an enlarged scale, of part of the apparatus illustrated in FIG. 6, disclosing a bleeder portion of the apparatus;

FIG. 15 is a view similar to FIG. 14 showing the apparatus in condition for bleeding pressure from the cylinder mechanism of the packer apparatus;

FIG. 16 is an enlarged cross-section taken along the line 1616 on FIG. 1;

FIG. 17 is an enlarged fragmentary longitudinal section taken along the line 17-17 on FIG. 2b;

FIG. 18 is a cross-section taken along the line 1818 on FIG. 13c;

FIG. 19 is a longitudinal section, with parts broken away, of a force multiplier embodied in the apparatus in its initial position;

FIG. 19a is a view similar to FIG. 19 of the force multiplier in another operating condition;

FIG. 20 is an enlarged cross-section taken along the line 29-20 on FIG. 1;

FIGS. 21 and 22 together constitute an elevational view and longitudinal section of the tubular portions interconnecting the upper and lower packers, FIG. 22 being a lower continuation of FIG. 21; and

FIG. 23 is a View of the ported portion of the apparatus shown in FIG. 21 in another operative position.

A well packer A or B is illustrated in the drawings which can be lowered within and set in a well casing C for the purpose of conducting well production from a plurality of separate producing zones D, E, F in the well bore through separate paths and separate parallel tubular strings G, H to the top of the well bore. A plurality of well packers A, B (FIGS. 3a, 3b, 30) may be run in the well bore in tandem relation and set hydraulically therewithin, being placed in appropriate relation to a third packer I which may have been previously set in the well bore or well casing.

, As shown, the well packer I may have been previously anchored in packedotf condition in the well casing above lower casing perforations 10 communicating with the lower producing zone D in the well bore. An intermediate packer B is to be disposed in the well casing above a set of intermediate casing perforations 11 communicating with the intermediate producing zone E, and an upper well packer A is to be set in the well casing C above upper casing perforations 12 communicating with the upper producing zone F. The upper packer A is placed in communication with a pair of parallel tubular strings G, H extending to the top of the well bore. Production from the intermediate and lower zones E, F may be conducted selectively to the top of the well bore.

The upper and intermediate packers A, B are structurally the same. Prior to being run in the well bore, they may be conditioned or adjusted for setting hydraulically at different times. Thus, the intermediate well packer B may be adjusted to be set hydraulically without effecting hydraulic setting of the upper packer A, the latter packer being hydraulically set at any desiredtime thereafter, which time interval may be a matter of minutes.

As disclosed, each well packer A, B includes first and second parallel

tubular body members

13, 14, the second body member 14 having an upper threaded pin 15 threaded in a lower bore 16 in a receptacle or parallel string head 17. In connection with the upper packer A, a first tubular string G is connected to the first body member 13 which extends slidably through the receptacle 17,

a second tubular string H extending to the top of the well bore and communicating with a second passage 18 extending through the parallel string head. The second tubular string H can be lowered from the top of the well bore into the casing C for reception within the second passage 18. As shown (FIG. 11a), the lower portion of the second tubular string includes a sub 19 having a suit able side seal 20 mounted thereon for sealing against the Wall of the second passage 18. Depending from this sub is a latch device, including a plurality of spring-like arms 21 having central cam projections or fingers 22 adapted to be received under a flange or shoulder 23 in the parallel string head 17 below the sealing region of the second passage. These fingers are engageable with the head shoulder 23 when the second tubular string H is being inserted in the passage 18, such engagement springing the fingers 22 and arms 21 inwardly sufficiently so that the fingers ride past the shoulder 23 to a position therebelow for the purpose of releasably retaining the second tubular string H in the second passage with its seal engaging the wall of the latter. The exertion of a sufficient upward pull on the second tubular string causes the fingers 22 to engage the lower tapered surface 24 of the head shoulder, which cams or forces the fingers and the latch arms 21 inwardly until the fingers ride past the flange 23, thereby releasing the second tubular string H from the head 17 and permitting its complete withdrawal from the second passage 18, and, if desired, enabling it to be removed entirely from the well casing C and the well bore.

In the use of the well packer apparatus, it may be lowered in the well casing on the first tubular string G to the desired setting location, if only one packer is involved, or to appropriately locate the tandem intermediate and upper packers A, B in the well casing. Thereafter, the second tubular string H is lowered in the well casing, and will engage an inclined head or guide surface 25 at the top of the receptacle 17, which will guide or steer the lower portion of the second tubular string toward and into the second passage 18.

The first tubular string G is suitably connected, as by means of a coupling 26, to the first tubular body member 13 of the upper packer A which extends slidably through a first longitudinal passage 27 in the receptacle or head 17. The first tubular body member extends completely through the packer and has a suitable lower connection 28 for attachment to the devices therebelow, as, for example, to first tubing 29 which may extend downwardly therefrom for appropriate association or connection with the packer B therebelow, and, more particularly for connection to the first tubular body member 13 of the intermediate packer B.

The first and second

tubular body members

13, 14 of a packer A or B extend through an upper connector 30 engaging the lower end of the parallel string head 17, this upper connector being secured to the second tubular body or mandrel 14 by a two-piece ring 31 located in a peripheral groove 32 in the second tubular body member and received within a counterbore 33 in the upper connector, and also contacting an upper insert 34 through which the body members extend. The insert 34 is clamped to the lower end of the upper connector 30, and also against the two-piece coupling ring 31 of the second tubular body member 14, by an uppergauge ring 35 threaded on the upper connector 30 and having an inwardly directed flange 36 engaging the upper insert. The upper insert 34 also is adapted to contact a two-piece stop ring 37 mounted in a peripheral groove 38 in the first tubular body member 13, the ring being received within an enlarged diameter bore 39 through the upper connector 30 which communicates with a counterbore 40 extending upwardly in the receptacle 17 from its lower end, and whichterminates in a downwardly facing shoulder 41. The first tubular body member 13 may be moved by the first tubular string G upwardly of the connector 30 and the receptacle 17, its stop ring 37 sliding in the connector bore 39 and in the counterbore 40 until it engages the downwardly facing receptacle shoulder 41.

The first and second

tubular body members

13, 14 extend downwardly through and into an initially and normally retracted packing structure 42, an expander 43, a slip structure 44 for anchoring the well packer against longitudinal movement in the well casing, and a hydraulic actuating mechanism 45. The packing structure 42 can assume any desired form. As shown, it includes a plurality of pliant, elastic packing elements 46, made of rubber or rubber-like material, and intervening spacers 47, through which the

body members

13, 14 extend. The upper packing element 46 engages the upper gauge ring 35 and insert 34, its lower end engaging a spacer 47, which, in turn, engages an intermediate packing element 46 contacting a spacer 47 that engages a lower packing element 46 which contacts a lower insert 48 slidably receiving the body members. The lower packing element also contacts a lower gauge ring 49 having an inwardly directed flange 50 clamping the lower insert 48 against the upper end of the expander 43.

The expander 43 is provided with a pair of bores 51 through which the first and

second body members

13, 14 slidably extend. The expander 43, lower insert 48 and lower gauge ring 49 are movable as a unit relative to the first and second

tubular body members

13, 14. Downward movement of these parts relative to the second tubular body member 14 is prevented by a two-piece stop ring 52 mounted in a peripheral groove 53 in the second body member 14 and engaging the lower end of the lower insert 48. The bore 51 through the expander 43 below the insert 48 is of an enlar ed diameter along an extended length to permit relative downward movement of the second body member 14. As a precautionary measure, such relative downward movement is limited by engagement of. the stop ring 52 with the lower end 54 of the expander defining the end of its enlarged diameter bore.

The lower expander 43 has a plurality of spaced slots 54a, the bases 55 of which provide expander surfaces tapering in a downward and inward direction. The upper portions of slips 56 are disposed in these slots, the inner portions of the slips having tapered surfaces 57 companion to the expander surfaces 55 and movable longitudinally relative thereto, as well as laterally outwardly and inwardly into and from engagement with the wall of the surrounding well casing C. Each slip 56 has opposed side tongues 58 slidably in companion grooves 59 in the expander 43, so that the slips are moved positively from an expanded to a retracted position upon longitudinal separating movement between the expander 43 and slips 56, and are also capable of being held positively in a retracted position. The lower ends of the slips are connected to a slip ring 60 having a pair of bores 61 through which the

body members

13, 14 extend, there being a slidable connection between lower T-shaped heads 62 of the slips and companion T-shaped grooves 63 formed in the slip ring. Such T-shaped

connections

62, 63 causes the slips 56 to move jointly longitudinally with the slip ring 60 while permitting their movement radially of the slip ring toward the well casing and from the well casing. To facilitate such radial movement, the T-shaped heads 62 and the companion grooves 63 in the slip ring are inclined to a small extent in an outward and downward direction.

The first and second tubular body-

members

13, 14 extend downwardly from the slip ring through a thrust sleeve structure 64 and into the first and second

parallel passages

65, 66 of a hydraulic housing 67 forming a portion of the hydraulic actuating mechanism 45. The thrust sleeve 64 interconnects the hydraulic housing 67 with the slip ring 60. As shown, the thrust sleeve is formed in two halves and has an upper internal flange 68 received within a peripheral groove 69 in the slip ring 60. Similarly, the thrust sleeve 64 has a lower internal flange 70 received within a peripheral groove 71 in the upper portion of the hydraulic housing 67. The upper flange 68 is prevented from removal from the slip ring groove 69 by a retainer ring 72 encompassing the slip ring 60 and an upwardly extending skirt 73 on the thrust sleeve. Upward longitudinal movement of the retainer ring 72 from the skirt 73 is prevented by engagement of the ring 72 with the slip ring 60. The slip ring has circumferentially spaced recesses 74 therein and the retainer ring has companion teeth 75 thereon. When the teeth 75 are disaligned with the recesses 74, the ring 72 encompasses the thrust sleeve skirt 73, being held in such disaligned position by screws 76 disposed on opposite sides of one of the teeth 75. When disassembly of the thrust sleeve is to occur, the screws 76 are removed and the ring 72 turned to place its teeth 75 in alignment with the slip ring recesses 74, the retainer rin 72 then being shiftable upwardly from an encompassing relation to the skirt 73, in view of the ability of its teeth 75 to enter the slip ring recesses 74.

In a similar manner, the lower flange is prevented from being removed from its groove 71 by a retainer ring 72 encompassing the hydraulic housing 67, and also a lower skirt 73 of the thrust sleeve, the lower retainer ring 72 being held in appropriate assembled relation in the same manner as the upper retainer ring, having circumferentially spaced teeth adapted to move into circumferentially spaced recesses 74 in the hydraulic housing 67, which are substantially the same as the recesses 74 in the slipring 60. Screws 76 disposed on opposite sides of a lower ring tooth 75 and threaded into the housing 67 will prevent turning of the lower ring 72 into a position aligned with the housing recesses 74.

The first tubular body member 13 is releasably connected to the lower portion of the hydraulic housing 67, and, for that matter, also to the slip ring 69 so that it cannot move longitudinally with respect to either of these parts when the well packer is being lowered in the well casing. The releasable connection between the first body member 13 and the hydraulic housing 67 includes a shearable device. An upper face cam 80 is mounted in a counterbore 81 in the lower portion of the housing 67 and is fixed to the housing by a screw 81a or the like, its upper end bearing against a housing shoulder 82. This face cam 80 engages a companion driving face cam or sleeve 83 surrounding the body member 13 and rotatable therewith by securing keys 84 to the cam sleeve received within keyways or grooves 85 in the body member. The lower end of the driving cam 83 engages the outer portion of a shear ring 86, the inner portion of which extends within a peripheral groove 87 in the mandrel 13. This shear ring may be made of two halves and is held inwardly in the groove 87 by a retainer ring 38 which encompasses the shear ring 86 and which has a recess 89 therebelow to permit the outer portion of the shear ring to move downwardly thereinto along the mandrel 13 after it has been sheared or detached from the inner portion of the shear ring. The driving cam sleeve 83 can also shift downwardly into the recess 89 in the retainer ring. The re tainer ring 88 is held in its upper position surrounding the shear ring 86 by a guide ring 90 threaded on the housing 67 and through which the first body member 13 extends, as well as a tubular sub 91 threadedly secured to the lower end of the hydraulic housing in alignment with the second body member 14.

The first body member 13 is prevented from moving downwardly relative to the hydraulic housing 67 and the slip ring 60 connected thereto by a stop ring 92 which is in the form of a C ring adjustably threaded on the mandrel 13 and engaging an upper shoulder 93 on the hydraulic housing. Engagement of the adjustable st-op ring 92 with the housing 67 prevents any downward force from being transmitted from the tubular body to the'shear ring 86, which might prematurely disrupt the ring 86. Upward movement of the mandrel 13 is prevented by the shear ring 86 engaging the lower end of the cam sleeve 83, which, in turn, engages the face cam 80 fixed to the housing, and which also engages the housing shoulder 82.

The driving cam 83 is initially prevented from being turned by the mandrel 13 by one or more shear screws 94 threaded into the housing 67 and into the driving cam. The application of sufficient torque on the first body member or mandrel 13' can disrupt this screw 94, allowing the driving cam 83 to turn and causing the coengaging inclined cam faces 95 to force the sleeve 83 downwardly against the shear ring 86, disrupting the latter, and thereby freeing the mandrel 13 for upward movement within the hydraulic housing 67, and, for that matter, as explained hereinbelow, for upward movement to release the well packer from the well casing after it has been set there'within.

Thefirst body member 13 and also the second body member 14 are releasably locked to the slip ring 60 to prevent their longitudinal movement with respect to this latter part. Since the upper end 15 of the second body member 14 is attached to the receptacle 17, its securing of the slip ring 60 prevents the receptacle from moving toward the slip ring, which is essential for outward expansion of the slips 56 and packing elements 46 against the well casing C. The releasable locking of the first body member 13 to the slip ring 60 will prevent any upward thrust of the tubular mandrel 13 from being transmitted to the shear ring 86, and thereby inadvertently shear or disrupt the latter.

The lock devices for initially securing each

body member

13, 14 to the slip ring 60 include a lock sleeve 96 surrounding each body member, with its upper portion cirwith a plurality of circumferentially spaced longitudinal slots forming legs 98 terminating in inwardly directed fingers 99 received within a circumferential groove 100 in its associated

body member

13 or 14. The fingers of both sleeves 96 are initially held in their grooves 100 by an encompassing connector plate 101 through which each body member slidably extends. It is necessary to shift the connector plate 101 downwardly free from the fingers 99 to disconnect the

body members

13, 14 from the slip ring 60 and permit their longitudinal movement with respect thereto.

Initially, the connector plate 101 is held in its upward position by

shear screws

102, 103, 104 attaching it to the first body member 13. As shown, an upper shear screw 102 secures the connector plate 101 to the body member 13 and two longitudinally spaced shear screws 103, 104 are connected to the plate and are disposed within an elongate slot or groove 105 in the first body member 13 (see FIG. 17). With the shear screw, frangible arrangement disclosed, all three screws are eifective for resisting rotation of the first body member 13 relative to the connector plate 101. However, only one of the screws is effective at any time for preventing longitudinal movement.

of the connector plate 101 relative to the first body member or mandrel 13. Assuming a downward force to be imposed on the connector plate 101, such downward force is at first transmitted only through the uppermost shear screw 102 to the first body member 13, since this screw makes a snug fit in a socket 106 in the body member, and the other two

screws

103, 104 are spaced from the lower end of the elongate groove 105 and also from one another. Accordingly, the imposition of sufiicient downward force on the connector plate 101 will first shear the upper screw 102, the plate then moving downwardly until the lower screw 104 engages the lower end of the groove 105. The imposition of sufficient force to overcome the shear value of the lower screw 104 will result in its disruption and a further downward movement of the connector plate 101 along the body member 13, until the intermediate screw 103 engages the broken inner portion of the lower screw, which is in contact with the lower end of the groove. The imposition of sufficient downward force on the connector plate to overcome the shear strength of the intermediate screw 103 will then result in its disruption and the full freeing of the connector plate from the first body total of 18,000 pounds would be available for resisting turning or torque of the first body member; whereas, only 6,000 pounds, the shear strength of a single screw, re-

sists downward movement of the connector plate 101 along the first body member 13.

The force for setting the well packer is transmitted through the connector plate 101, as described hereinbelow, to the second body member 14. As shown, the second body member has a thrust ring 107 thereon spaced initially below the upper shoulder 108 of a counterbore 109 in the connector plate. The connect-or plate can move downwardly along both

body members

13, 14, following disruption of the shear screws 102, 103, 104, until the connector plate shoulder 10% engages the second body ring 107, at which time the connector plate 101 will have been removed from the latch fingers 99 of both latch sleeves 96, which will then allow the connector plate to shift the second body member 14 downwardly within the slip ring 60. In view of the shearing of the

screws

102, 103, 104 initially securing the connector plate to the first body member, such downward movement will not tend to move the first body member 13 downwardly, which will remain in its fixed position, in view of its thrust ring 92 engaging the shoulder 93. Its upward movement is prevented by the lower shear ring mechanism -88.

Downward movement of the second body 14 with respect to the slip ring 60 results in outward expansion of the slips 56 and shortening and outward expansion of the packing structure 42 into engagement with the wall of the Well casing C. Such downward movement and setting of the normally retracted parts of the well packer are effected hydraulically, and more specifically by the hydrostatic head of fluid in the well bore or well casing. The hydraulic housing 67 is provided with a plurality of cylinders 110 closed at their lower ends, each cylinder containing a piston structure that includes a piston 111 suitably secured to a piston rod 112 extending upwardly from the piston and through an accumulator and cylinder head structure 113. Such accumulator structure includes a movable cylinder head 114, through which the rod extends, slidable along the wall of the cylinder and having seal rings 115, 116 slidably sealing against the cylinder wall and the piston rod. A stop ring and spring thrust member 117 surround the piston rod 112 and is threadedly secured to the movable cylinder head 1 14, extending upwardly within a spring housing 118 that extends downwardly within the cylinder 1 10 with its upper end lthreadedly secured to the hydraulic housing 67. A plurality of Belleville washers or conical spring members 119 are disposed within the housing 1 18 around the rod 112, the lower end of the conical spring assembly engaging the spring thrust member 117, and its upper end engaging a spring seat 120 surrounding the piston rod 112 and thre'adedly secured within the spring housing 118. Leakage around the spring housing 118 is prevented by one or more seal rings 1-21 thereon engaging the wall of the cylinder 110; whereas, leakage of fluid along the piston rod 112 is prevented by one or more seal rings 122 mounted in the spring seat 120 and slidably and sealingly engaging the piston rod.

The springs 119 exert a constant force on the stop ring and thrust member 117 to shift it downwardly to the extent limited by engagement of the stop ring 117 with a housing shoulder 123. The exertion of sufficient hydraulic force in the cylinder 1 on the movable cylinder head 1 14 can shift the latter upwardly and store energy or spring force in the springs 1*19, tor the purpose described hereinbelow.

Each cylinder communicates with an inlet port 124 above its piston 11d and immediately below its movable cylinder head 114, communicating through a check valve 125, and also through a balanced piston valve 126, with the second passage 66 through the hydraulic housing 67, into which the second body member 14 extends. Each cylinder also communicates with pressure equalizing or vent

ports

127, 128 communicating through breakable plug devices i129, 130 with the first passage 65 through the hydraulic housing 67, these vent ports opening into a cylinder immediately below its head 114, and also into the lower end of the cylinder below the piston.

Each piston has a suitable seal ring structure 131 thereon slidably and sealingly engaging the wall of the cylinder and held on the piston by a suitable retainer ring 132. Initially, the cylinder space 133 below thepiston contains air at atmospheric pressure, the

vent ports

127, 128 leading from a cylinder on opposite sides of its piston each being closed by a transverse breakable closure plug 134 extending across a vent port with side ports 135 communicating therewith that open into a central passage 136, the inner end of which is closed by an end wall 167 of the plug extending into the first housing passage 65 and into a socket 138 in the first body member 13. The breakable plug 134 is held in position by a closure plug 139 threaded into a housing bore 140. Leakage of fluid from the bore containing the breakable plug and closure plug is prevented by side seal rings 141 mounted thereon and engaging the wall of the bore. The break-able plug 134 is also prevented from longitudinal shifting by a set screw 142 threaded in the housing and extending into a peripheral groove 143 in the breakable plug. The outer portion 144 of the central passage 136 through the breakable pl-ug may be threaded to facilitate removal of the plug from its bore, after the closure plug 139 has been removed, by threading a suitable tool or rod (not shown) thereinto, which will then enable the break-able plug 134 to be pulled out of the housing bore 140.

The cylinders 110 above the pistons 111 are in fluid communication with each other through a transverse passage 145 extending therebetween, and the lower portions of the cylinders below the pistons are in communication with each other through an interconnecting pass-age 146 provided in the hydraulic housing. Accordingly, the introduction of fluid pressure into one cylinder above its piston will result in the same fluid pressure passing through the interconnecting passage 145 to the other cylinder above the piston. Similarly, the venting of one cylinder above the piston will also result in the venting of the other cylinder. The placing of one cylinder below its piston in communication with the first passage 65 through the housing 67 will also result in the corresponding placing of the other cylinder in communication with such passage because of the interconnecting passage 146.

The cylinder space 133 below each piston 111 contains air initially at atmospheric pressure, such cylinder space being closed by the breakable plug device 130 to prevent any fluid pressure from entering the lower end of one cylinder, as well as the lower end of the other cylinder. Fluid under pressure from the second housing passage 66 is initially prevented from entering an inlet port 150 opening into the balanced piston valve structure 126, and communicating through the check valve 125 with the inlet port 124 to a cylinder 110. The first-mentioned inlet port 150 opens into the second passage 66 through the hydraulic housing, which is closed initially by a sleeve valve 151 in the second passage secured to the lower end of the second body member 14 by shear screws 152. The valve sleeve carries suitable spaced side seal rings 153 sealingly engaging with the wall of the second housing passage on opposite sides of the inlet port 150. The valve sleeve has circumferentially spaced longitudinal slots in its lower portion providing spring-like legs 154 terminating in fingers 155 which project inwardly of the sleeve to an eitective internal diameter less than the internal diameter through the second body member 14, and also through the upper imperforate portion of the valve sleeve 151. When a suitable tripping ball valve element 156 is lowered or pumped through the second tubular string H, it passes through the second body member 14 and comes to rest upon the fingers 155. Thereafter, fluid pressure can be built up of a suflicient value to overcome the shear strength of the screws 152, shifting the sleeve valve 151 downwardly in the housing passage 66 to a position opening the inlet port 150 and allowing fluid pressure to flow therethrough and into the balanced piston valve structure 126 (described hereinbelow). When the balanced piston valve structure is opened, such fluid can then flow through the check valve 125 and through the

ports

124, 145 communicating with the cylinders above the pistons 111, for the purpose of shifting the pistons in a downward direction. The valve sleeve 151 is shifted downwardly hydraulically to a position in which its fingers 155 are aligned with a circumferential housing recess 157, the fingers expanding outwardly into such recess to increase their internal diameter and allow the ball 156 to pass downwardly therethrough and out of the well packer into the well casing C, or downwardly out of an upper well packer A and into a lower well packer B, assuming a tandem arrangement of well packers is being run in the well casing for setting therewithin.

When the hydrostatic head of fluid in the well casing can act downwardly on the pistons 111, they move downwardly pulling the rods 112 downwardly with them. Thrust nuts 158 threaded on the piston rods 112 and received within counterbores 159 in the connector plate 101 transmit the downward movement of the rods to the connector plate 101. Initially, the connector plate 101 is held in an upward position by the shear screws 102, 103,

104 attaching them to the first body member 13. When in this condition, the upper end 160 of each piston rod is disposed in an atmospheric chamber 161 in the slip ring 60, fluid being prevented from passing into this chamber by a suitable side seal ring 162 on the upper end of each rod engaging the cylindrical wall of the atmospheric chamber 161. In view of the sealing of the upper end of each rod in its associated atmospheric chamber, the hydrostatic head of fluid cannot act initially on the upper end of the rod 112, tending to shift it downwardly. However, when the hydrostatic head of fluid acts on the pistons 111 to exert a sufficient force thereon and on the rods 112 to shear the

screws

102, 103, 104 and move the rods and connector plate 101 downwardly with respect to the slip ring 60, the upper ends 160 of the rods are pulled out of the atmospheric chamber 161, allowing the hydrostatic head of fluid to act in a downward direction over the entire cross-sectional area of the piston rods. In effect, the hydrostatic head of fluid can then act in a downward direction over the entire cross-sectional area of each piston 111, bringing to a maximum the total hydraulic force available for downward movement of the piston rods and connector plate.

Each well packer A, B has a control unit (FIGS. 8 to 10) incorporated therein which includes the balanced piston valve structure 126, so that the well packer can be preadjusted to allow the fluid pressure to pass into its cylinders for the purpose of setting the well packer upon downward shifting of the valve sleeve 151 within the second housing passage 66, or to prevent setting of the packer as a result of such downward shifting of the sleeve valve, until an appropriate pressure differential has been imparted to the fluid in the second housing passage 66. Moreover, it is desired to trap fluid pressure in each cylinder 110 to hold the well packer in packed-off condition, despite the fact that the hydrostatic head of fluid in the well casing may subsequently diminsh considerably, as, for example, as might result from installation of gaslift equipment in the well casing.

As specifically disclosed, the control unit for the packer includes a valve body 165 extending downwardly into a longitudinal chamber 166 in the hydraulic housing 67, the upper portion 166 of the valve body being threadedly secured to the housing. The valve body has a central passage 167 therethrough and side ports 168 communicating with this central passage and with the inlet port 150 opening into the second housing passage 66. Leakage of fluid around the valve body 165 is prevented by suitable seal rings 169 mounted thereon and engaging the wall of the housing chamber 166 on opposite sides of the ports 168. A piston valve structure 170 is slidable longitudinally in the valve body 165, extending upwardly through a stop member and closure 171 threaded into the upper end of the valve body. Sliding of the piston valve member 170 may be facilitated by providing an enlarged guide portion 172 thereon slidable against the bore wall of the valve body 165.

The piston valve member 170 may be disposed in a position preventing communication between its ports 168 and a lower central passage 173 through the piston. Thus, the piston structure includes a lower head 174 slidable in a cylindrical valve seat 173 in the lower portion of the valve body 165, and also an upper head 175 slidable in the cylindrical bore 167 of the valve body. The lower piston head 174 is of a much smaller diameter than the upper piston head 175, so that fluid pressure within the valve body between the piston-s can act over a larger area of the upper piston head and shift the entire piston structure 170 upwardly to a position fully removing the lower piston head 174 from its cylindrical seat 173 and opening this central passage 173 to communication with the body ports 168. A suitable seal ring 176 is mounted on the lower head for sealing engagement against the cylindrical valve seat 173, a seal ring 177 also being mounted on the upper head 175 for sealing engagement with the wall of the cylindrical valve body bore 167. Another seal ring 178 is mounted on the piston and slidably seals against the cylindrical wall of the end body closure member 171.

The piston valve member 170 is balanced against hydraulic shifting under the action of the hydrostatic head of fluid in the well bore. The valve body 165 between the upper piston 175 and the seal ring 178 on the upper steam portion 179 of the piston structure 170 initially contains air at atmospheric pressure. The hydrostatic head of fluid in the well bore is acting in a downward direction over the entire cross-sectional area T of the steam portion 170 of the piston valve. When the inlet port 150 is open, the hydrostatic head of fluid is also acting in a downward direction over the annular area S of the lower piston head 174. Such hydrostatic head of fluid is acting in an upward direction on the larger upper piston 175 over its annular area R. The piston valve parts are so proportioned that the area R equals the sum of the areas S and T. Accordingly, the hydrostatic head of fluid in the well bore is acting over equal and opposite areas on the piston valve structure 170 and cannot efiect shifting of such piston valve in an upward direction.

The control valve unit can be conditioned initially with its parts in the position disclosed in FIG. 8, preventing communication between the valve body port 168 and its central passage 173 below the lower piston head 174. The piston valve may be retained in this position by a shear screw 180 threaded through the closure member 171, with its inner end extending within a peripheral groove 181 in the valve stem 179. Appropriate location of the groove 181 in alignment with the shear screw 180 and limiting of downward movement of the piston valve member 170 within the valve body housing 165 are obtained by engagement of a stop nut 182 threaded on the upper end of the stem 179 with the upper end of the enclosure member 17'1, inadvertent loosening of the nut 182 being prevented by a lock nut 183 threaded on the stern and bearing against the stop nut.

Upon the provision of fluid under suflicient pressure within the valve body between its upper and lower piston heads 175, 174, such pressure will act in an upward direction on the greater area of the upper piston head to shear the screw 1'80 and shift the piston valve device upwardly to remove the lower head 174 from its cylindrical seat and the central passage 173 in the valve body 165, the upward movement being limited by engagement of the guide 172 with the lower end of the closure memher 171. The stem 179 of the piston valve member 170 carries a latch or catch 184 in a slot 185, which is pivot ally mounted on a pin 186 extending across the slot, the latch being initially confined within the stem 179 by the encompassing closure member 171 (FIG. 8). However, when the piston valve 170 is shifted to an upward position, the latch 1 84 is disposed above the closure member 171, whereupon a spring 187 encircling the pivot pin 186, with one arm 188 bearing against the stem 179 at the upper end of the slot and the other arm 189 engaging the catch 184, will swing the catch 184 in a counterclockwise direction, as seen in FIGS. 8 and 9, placing it above the closure member 171. Any tendency for the piston valve member 170 to shift downwardly in the valve body is then precluded by engagement of the latch 184 with the closure member.

If desired, the control unit can first be adjusted so that the piston valve 126 is in the open position illustrated in FIG. 9. The shear screw 180 need merely be omitted and the piston valve member 170 moved upwardly manually until its latch 184 is disposed above the closure member 171, the latch then precluding downward movement of the piston valve to a position placing its lower piston head 174 within its cylindrical valve seat 173.

Assuming the piston valve device 126 to be open, fluid can now pass from the second passage 66 in the fluid actuator housing 67 and through the

ports

150, 168 into the

central passage

167, 173. Such fluid, if under a sufficient pressure, will open the check valve 125 and pass into the port 124 leading into one of the cylinders 110 above its actuating piston 111. As disclosed, the check valve 125 includes a valve housing 190, the upper end of which is threadedly secured to the lower end of the valve body 165 of the piston valve 126. A valve stem 191 is slidable in the lower portion of the valve housing 190, having a valve head 192 adapted to engage a rubber seat 193 suitably bonded to the exterior of the valve body 165. A helical compression spring 194 surrounds the valve stem 191, its lower end engaging a spring seat 195 provided by the housing, and its upper end engaging the check valve head 192 to urge the head against the elastic seat 193. When the fluid pressure above the valve head 192 overcomes the force of the spring 194, the head is shifted downwardly from engagement with its companion seat 193, the head and valve stem 191 sliding downwardly within the housing until the head 192 is disposed below the upper ends of a plurality of longitudinal slots a in the housing 190 which communicate with the port 124 leading to a cylinder 110. If the pressure in the valve body passage 173 decreases sufliciently, the spring 194 will shift the valve head back into engagement with its seat 193, the pressure in the cylinder 110 being prevented from bleeding therefrom.

The first body member 13 has longitudinally spaced sockets 138 receiving the inner ends 137 of the breakable plugs 134. The body member 13 also has a plurality of longitudinal external grooves 196 thereon which will facilitate bleeding of fluid from the cylinders 110, and also the entry of fluid thereinto, following actuation of the first body member 13 to disrupt or break the outer ends 137 of the plugs from the remainder of the plugs 134, in order to open their central passages 136. Plug breaking will occur either as a result of turning of the first body member 13, or as a result of moving the first body member 13 longitudinally within the hydraulic housing 67.

Assuming that only a single hydraulically actuated packer is to be run in and set in the well casing, its first body member 13 is secured to the first tubular string G with the parts in the retracted position illustrated in FIGS. 2a and 2b. If desired, the control unit may be placed in the condition illustrated in FIG. 9, with the shear screw 18% omitted so that the central passage through the

valve body

167, 173 communicates with the body ports 168 and with the inlet port 150 leading into the second passage 66. The well packer is lowered by the first tubular string G in the well casing C to the desired setting point, after which the second tubular string H is lowered in the well casing alongside the first tubular string, engaging the upper head and shifting downwardly into the second receptacle passage 18, becoming latched thereto. If desired, connections to the first and second tubular strings G, H can be made at the top of the well bore. It is unnecessary to thereafter longitudinally move any of the tubular strings. The well bore can now be conditioned by pumping circulating fluid down through the second tubular string H, such fluid passing through the second passage 66 of the packer apparatus and discharging from the lower coupling member 91 into the casing, forcing the drilling mud, or other undesired fluids in'the casing, upwardly around the packer and around the tubular strings G, H to the top of the well bore.

When it is desired to set the well packer, a tripping ball 156 is pumped down the second tubular string H, passing into the second body member 14 and coming to rest upon the fingers 155 of the valve sleeve 151. The building up of pressure in the second tubular string to a sufiicient value will overcome the strength of the shear screws 152, disrupting the latter and shifting the sleeve valve downwardly to a position opening the inlet port 150, the sleeve valve 151 moving downwardly until its fingers 155 expand into the housing recess 157, allowing the ball to move down through the tubular connector or coupling 91 and completely out of the packer, dropping into the well casing. The hydrostatic head of fluid in the well bore can now pass through the inlet port 150 and through the valve body ports 168 into the

central passage

167, 173 of the latter, shifting the

check valve member

192, 191 downwardly from its seat 193, and moving through the inlet port 124 into a cylinder 110 above a piston 111 and through the intercommunicating port or passage 145 into the other cylinder 110 above its piston. The hydrostatic head of fluid is present in both cylinders, acting upwardly on the cylinder heads 114, moving them upwardly and storing energy in the conical spring assemblies 119, which'may be collapsed to solid height.

The pistons 111 move downwardly in the cylinder 1111, shifting the rods 112 downwardly with them and forcing the connector plate 101 downwardly after shearing the

screws

1112, 103, 104 securing the connector plate to thefirst body member 13. The connector plate moves downwardly into engagement with the second body member thrust ring 107 and completely from encompassing relation to the latch fingers 99, allowing the latter to expand from-the body member grooves 100. The connector plate engages the second body member ring 107 and shifts the second body member 14 downwardly within the slip ring 60, shifting the receptacle 17 connected to the second body member, upper connector 31), upper insert 34, and upper gauge ring downwardly toward the slip ring 60. The slip ring cannot move downwardly at this time, since it is attached to the first body member 13 through the thrust sleeve 64, hydraulic housing 67,

cam sleeves

80, 33, and shear ring 86. Accordingly,

the receptacle 17, upper connector 33, upper insert 34, and upper gauge ring 35 move downwardly, carrying the packing structure 42 and expander 43 downwardly with them, effecting a shifting of the expander downwardly along the slips 56 and expanding the latter outwardly into engagement with the wall of the well casing C, precluding further downward movement of the expander 43. Continued downward movement of the second body member 14 along the first body member 13 will then move the upper receptacle 17, upper connector 31 upper insert 34, and upper gauge ring 35 toward the expander, shortening the packing structure 42 and expanding the packing elements 46 outwardly against the wall of the well casing C and firmly into sealing engagement will the

tubular body members

13, 14 extending therethrough. The well packer is now in packed-off condition within the well casing (FIGS. 11a, 11b).

The hydrostatic head of fluid is normally sufiicient and available to enter the cylinders 110 through the check valve to act constantly upon the pistons 111 and urge them downwardly in their cylinders 110, maintaining the slips 56 and packing structure 42 expanded against the wall of the well casing. If the hydrostatic head of fluid decreases below the closing force of the check valve spring 154, the check valve 125 closes and traps pressure in the cylinders 1111, such pressure being constantly exerted upon the pistons, urging them in a downward direction and maintaining the packing structure 42 and slips 56 firmly engaged against the wall of the well casing. If the packing elements 46 were to extrude around the companion spacer rings 47 and gauge rings 35, 49, so that the pistons 111 would move downwardly to a further extent in the cylinders 11th, in the absence of sufficient hydrostatic head in the well bore, the trapped pressure within the cylinders 11%) would be dissipated and the hydraulic force to maintain the packer anchored in packed-off condition in the well casing would no longer be present. However, with the packer illustrated and described, the pressure passing into the cylinders for the purpose of setting the packer has compressed the conical springs 119 and has stored energy therewithin, such springs tending to shift the movable cylinder heads 114 downwardly in the cylinders 110. Such springs constantly exert a force on the cylinder heads 114 to maintain pressure in the liquid within the cylinder 11d. Accordingly, if the pistons 111 were to move downwardly to a further extent within their cylinders, as a result of extrusion of packing material, or the like, an action which would ordinarily diminish the pressure in the cylinders or reduce such pressure to zero, the cylinder heads 114 would shift downwardly under the action of the conical spring washers 119- and maintain the liquid under pressure. In other words, the force of the springs 119 would then be transferred through the trapped liquid in the cylinders 11% to the pistons 111, urging them in a downward direction and thereby maintaining the slips 56 and packing structure 42 expanded against the wall of the well casing. In effect, the springs 119 function as a pressure accumlator to insure the presence of adequate pressure in the cylinders for holding the packer set in the well casing, despite the loss of hydrostatic head of fluid in the well casing, and despite downward movement of the pistons in the cylinders to a further extent as a result of extrusion or cold flow of the rubber or rubber-like packing elements 46.

Ordinarily, the first tubular body member 13 will be connected through an appropriate length of tubing to a packer therebelow, to conduct fluid from a lower production zone through the first tubular string G to the top of the well bore. Production from an upper zone between the lower packer and the packer A will pass into and through the second passage 66 through the packer and the second tubular string H to the top of the well bore.

In the event it is desired to release the packer from the well casing and remove it therefrom, the pressure in the cylinders 110 on opposite sides of the pistons 111 is equalized. Since the pressure on the high pressure side of the pistons 111 may be trapped, by virtue of closing of the check valve 125, the cylinder regions on the high pressure side of the pistons, as well as the cylinder regions on the atmospheric or low pressure side of the pistons, are open to the first passage simultaneously. A straight-line pull can be taken on the first tubular string G to pull upwardly on the first body member 13. If such pull is suflicient, it will disrupt the shear ring 86, as well as the inner ends 137 of the break plugs 134, opening the passages 136 through the break plugs and cstablishing communication therethrough between each cylinder on opposite sides of its piston 111 and the surrounding well bore, the communication being established through the clearance space between the first tubular body member 13 and the first passage 65 in the hydraulic housing, which space may be increased by virtue of the circumferentially spaced longitudinal grooves 196 in the exterior of the first body member. The fluid in the well bore can now pass into the cylinders 110 below the pistons 111 and any excess fluid pressure will bleed from the cylinders above the pistons 111. The conical springs 119 can expand to the extent determined by engagement of the stop rings 117 with the stop shoulders 123 on the housings 118.

Following equalizing of the pressure, the second tubular string H can be removed from the receptacle 17, if

- such removal has not been previously accomplished, by

taking a sufiicient upward pull on the second tubular string H which will cause the latch fingers 22 to engage the shoulder 23, shifting the fingers inwardly until they ride past the shoulder, whereupon the second tubular string H can be pulled completely out of the receptacle 17 and removed from the well bore.

An upward pull can now be taken on the first tubular string G, which will move the first body 13 upwardly until its ring 37 engages the receptacle shoulder 41. A continuation of the upward pull will move the receptacle 17, second body or mandrel member 14, and the parts above the packing 42 connected thereto, upwardly with respect to the expander 43, allowing the packing elements 46 to retract from the well casing. The second body member 14 will move upwardly until its ring 52 engages the lower insert 48, whereupon its continued upward movement will shift the expander upwardly relative to the slips 56, the slips being retracted from the well casing by virtue of the tongue and

groove interconnections

58, 59 with the expander 43. The well packer can now be elevated in the well casing through elevation of the first tubular string G and removed entirely therefrom.

In lieu of disrupting the break plugs 134 and the shear ring 86 by taking a direct upward pull on the first tubular string G and first body member 13, the break plugs and the shear ring can be disrupted by turning the first tubular string G and body member 13. The application of suflicient torque to the body member 13 will break the inner ends 137 of the plugs from their main portion to open their central passages 136. Such turning movement will also be transmitted to the cam sleeve 83. Initial turning of the cam sleeve will shear the screws 94 that attaches it to the hydraulic housing 67, after which turning of the sleeve 83 relative to the upper cam member will cause the latter to shift the sleeve 83 downwardly, exerting a sutficient force on the shear ring 86 to shear its outer portion from its inner portion disposed within the mandrel groove 87. Because of the angle of inclination of the cam faces of the coengaging cam members, a very great mechanical advantage is provided, so that a force equivalent to the torque imparted to the first tubular body member 13 is multiplied several times in exerting a longitudinal shearing force on the shear ring 86. A comparatively low torque can be converted to a very high shearing force on the ring 86 by use of the force multiplier 83, St).

The slips 56 heretofore described anchor the packer in the well casing against downward movement. If desired, it can also be anchored against upward n enent. The receptacle or head is provided with generally rat'ially disposed cylinders 220, the inner portions of which communicate with the second head passage 18 through intervening ports 221. Each cylinder contains a gripping member 22?. having wickers or teeth 223 adapted to embed themselves in the wall of the well casing C and resist upward movement. The gripping members are urged initially toward a retracted position completely within the cylinders 220 by helical compression springs 224, engaging retainers and spring seats 225 extending across vertical slots 226 in the gripping members and suitably secured to the receptacle 17, and also engaging the gripping members 222 themselves. The fluid pressure in the second passage 18 will pass through the ports 221 into the inner portions of the cylinders 220, urging the gripping members or pistons 222 outwardly into firm gripping engagement with the wall of the well casing. Leakage of fiuid around each gripping member is prevented by a suitable side seal :ring 227 slidably and sealingly engaging the wall of its cylinder 220.

In the event it is desired to release the well packer with pressure in the second passage 18 adequate to hold the gripping members 222 outwardly against the wall of the well casing C, the second tubular string H will first be removed from the receptacle to equalize the pressure on the interior and exterior of the gripping members, allowing the springs 224 to shift them inwardly to retracted position completely within the confines of the receptacle or head 17. Thereafter, the well packer can be released in the manner described above and removed from the well casing.

When latched in its open condition, as illustrated in FIG. 9, the control unit is ineffective to prevent setting of its Well packer upon shifting of the valve sleeve 151 from the position closing the second passage port 150. The control unit can be placed initially in the condition illustrated in FIG. 8, in which the central passage 173 through the valve body 165 is closed, the shear screw 180 securing the piston valve member 170 to the valve body, with the lower piston head 174 within its cylindrical seat 173 and closing its central passage. If the valve sleeve 151 were now to be shifted downwardly in the second passage 66 to open the port 150, fluid pressure could not pass downwardly through the valve body passage 173 to unseat the check valve 192 and enter the cylinders for the purpose of shifting the pistons 111 downwardly therewithin and effecting setting of the packer, unless the fluid pressure differential entering the valve body between its upper and lower piston heads 175, 174 is sufficiently high to overcome the shear strength of the screw 180 and shift the piston structure upwardly to the position illustrated in FIG. 9, thereby opening the central passage 173 through the valve body. The strength of the shear screw can be made quite large, so that a substantial pressure differential must be imposed through the second tubular string H before the piston valve 170 can be shifted from its closed to its open position.

If only a single packer were to be run in the well bore, the sleeve valve 151 within the second housing passage could be omitted, if desired, and the piston I valve 170 secured in its closed position by means of the shear screw 180, as illustrated in FIG. 8. When it is desired to set the well packer, the second housing passage 66 can be closed below its open port 150 by any suitable means, as by the ball valve element 156 engaging a tripping ball seat 229 secured by a shear screw 230, or the like, to a member 231 threaded on the lower end of the tubular connector 91. The shear screw 230 attaching the seat 229 to its associated member 231 requires a much greater fluid pressure to shear than is required to disrupt the screw 180 holding the piston valve member 170 in its valve closing position. When the ball 156 engages its seat 229, suflicient pressure can 17 be built up in the second passage 66 for action upon the piston valve 170 to disrupt its associated shear screw 180 and shift the piston valve to the open position shown in FIG. 9, whereupon the pressure in the second passage 66 can be increased to disrupt the shear screw 230 holding the seat 229 to its member 231, blowing the seat and the ball 156 completely out of the member 231, these parts dropping 'harmlessly into the well casing. The hydrostatic head of fluid can now unseat the

check valve member

192, 191 and enter the cylinders 111) to move the pistons 111 downwardly and set the well packer.

Packers A, B heretofore described can be run in tandem in the well casing C to secure production selectively from a plurality of zones E, F in the well bore. As disclosed in FIGS. 3a, 3b and 3c, the Well casing C is disposed in the well bore and passes through the lower, intermediate, and upper producing zones D, E, F, there being the lower, intermediate, and

upper casing perforations

10, 11, 12 opposite these zones. The well packer J of any suitable type may have previously been installed in the well casing C between the lower and intermediate casing perforations 10, 11. An intermediate well packer B and an upper well packer A are connected together by means of first and

second tubings

29, 250, the first tubing 29 being firmly secured to the lower end of the first body member 13 of the upper packer A and firmly secured to the upper end of the first body 13 of the intermediate packer member B. The second tubing 250 is secured to the connector 91 of the upper packer A that communicates with its second passage 66, and the lower end of the tubing string 250 fits within the second passage 18 of the receptacle 17 of the intermediate packer B. This second tubing 250 includes a telescopic joint 251 and also a ported structure 252 which can be conditioned to open its ports 253 to allow fluid from the upper production zone F to pass through the upper perforations 12 and into the second passage 66 of the upper packer, at which time the second tubing 250 below the ports 253 is closed. If desired, the ports 253 can be closed and communication with the second passage 66 of the intermediate packer B established through the tubing 250, so that production from the intermediate zone E can flow into the second passage 66 of the intermediate packer B, through the second tubing 25% and the second passage 66 of the upper packer A into the second tubular string H extending to the top of the well bore. The lower end of the first body 13 of the intermediate packer B has tubing 254 connected to it extending into the lower packer in appropriate sealing relation therewith, this lower tubing having lower perforations 255 through which production from the lower zone D can flow into and through the tubing 254, into the first body 13 of the intermediate packer B, through the first tubing 29 into the first body 13 of the upper packer A, continuing on up through the first tubular string G to the top of the well bore.

The intermediate packer B has the member 231 secured to its lower connector 91 containing the tripping ball seat 229 attached thereto by means of one or more shear screws 230.

The telescopic joint 251 is of any suitable type. As shown in FIG. 22, it includes an inner mandrel 256 telescopically arranged within an outer housing 257, there being a seal ring 258mounted on the mandrel slidably and sealingly engaging the wall of the housing to prevent leakage between the interior and exterior of the joint.

The side ported structure 252 can be of any known, suitable type. As shown in FIG. 21, it includes an outer housing 259, which may be made of several sections, having the ports 253 therethrough. A sleeve valve 260 extends initially across these ports to close the same, leakage of fluid through the ports being prevented by suitable side seals 261 on the sleeve engaging the wall of the housing 259. The sleeve valve is releasably retained in port closing position by an inherently, expandible split ring 262 mounted in a sleeve groove 263 and disposed within a companion internal groove 264 in the housing, as shown in FIG. 22. Through use of a suitable shifting mechanism (not shown), the sleeve 26% can be moved upwardly within the housing to align sleeve ports 265 with the housing ports 253, the split ring 262 snapping into an upper housing groove 266 to releasably hold the sleeve in its port opening position (FIG. 23).

After the sleeve 260 has been shifted to port opening position, the housing 259 below the ports 253 can be plugged by running a suitable blanking plug 267 through the tubular string H and through the second passage of the upper packer A. As disclosed in FIG. 23, this blanking plug includes a mandrel 268 having a central plug 269 below side ports 270 in the mandrel. The mandrel carries a suitable side seal 271 adapted to seal against an inner wall 273 of the housing 259 below its ports 253. The mandrel carries suitable lock levers 27 pivoted on hinge pins 275 and urged by springs 276 outwardly, the lock levers shifting into a coupling recess 277 formed between the upper end of the housing 259 and a section of the tubing 250 thereabove.

When the blanking plug device 267 shown in FIG. 23 is employed, fluid from below the side ported valve device 252 cannot pass upwardly through the tubing 251). Instead, it passes through the

side ports

253, 265, 270 into the tubular mandrel 268 and up through the tubing 250 into the second passage 66 of the upper packer A for continued upward movement through the second tubular string H to the top of the hole. Removal of the blanking plug 267 and shifting of the sleeve valve 260 back to its port closing position (FIG. 23) will allow production from the intermediate zone E to flow upwardly through the lower packer B and through the tubular string 250 into the upper packer A for upward passage through the second tubular string H to the top of the hole. Depending upon the position of the valve sleeve 260 and the presence or absence of the blanking plug 267, production can be secured selectively from either the intermediate or upper zones E, F for conveyance through the second tubular string H to the top of the well bore.

In running the tandem arrangement of packers A, B in the well casing C, they are secured together in appropriate spaced relation through use of the intervening first and

second tubings

29, 250, with the body member 13 of the lower packer B connected to a suitable length of tubing 254 so that such tubing will be placed in appropriate leak-proof relation to the lower packer I when .the intermediate packer B is disposed between the intermediate and upper perforations 11, 12 and the upper packer A is disposed above the upper perforations 12. The control unit of the intermediate packer B preferably will be placed in the condition illustrated in FIG. 9, in which the central passage 173 through the valve body is open, as also shown in FIG. 3b, and the control unit through the upper packer A will be placed in the closed condition, such as illustrated in FIG. 8 and FIG. 3a, the shear screw 180 holding the piston valve member in the closed position. The screw has a much greater shear strength than the screws 152 holding the sleeve valve 151 of the lower packer across the second passage port 150.

The tandem combination of packers A, B is run in a well casing on the first tubular string G until the tubing 254 is appropriately related to the lower packer J, at which time the intermediate and upper packers B, A will also be appropn'ately located in the well casing. The second tubular string H is now lowered in the well casing alongside the first tubular string and guided into the second passage 18 of the upper packer A and releasably latched thereto. The tubular strings G, H can be appropriately connected to other devices at the top of the well bore, so that they need no longer be moved longitudinally, and circulating fluid pumped down the second 19 tubularstring H, which fluid passes through the second passage 66 of the upper packer A and the second tubing 250, and through the second passage 66 of the intermediate packer B, the fluid discharging from its lower end. At this time, the side ports 253 of the second tubing 250 are closed. Such circulating fluid flows upwardly around both packers A, B and around the tubular strings G, H to the top of the Well bore, flushing drilling mud, and the like, ahead of it out of the well casing.

A tripping ball 156 is now pumped down the second tubular string H, passing into the second tubular body 14 of the upper packer A and engaging the valve sleeve fingers 155 of the upper packer. The building up of sufficient pressure will shear the screws 152 holding the sleeve 151 to the second body member 14, shifting the sleeve downwardly to a position opening the second passage port 150, the fingers 155 expanding into the recess 157 and allowing the ball 156 to continue moving downwardly through the second tubing 250 and into engagement with the valve sleeve 151 of the intermediate packer B. If desired, the sleeve valve 151 of the upper packer A can be omitted. The upper packer A cannot set at this time since its piston valve 170 is in the closed position, the shear screw 180 holding it in such position remaining intact. When the tripping ball engages the fingers 155 of the valve sleeve 151 of the intermediate packer, pressure can be built up in the second tubular string H and in the second passages 66 and intervening tubing 250 sufiicient to disrupt the shear screws 152 holding the sleeve to the second body member 14, allowing the sleeve to shift downwardly below the second passage ports 150, its fingers expanding outwardly into the recess 157 and allowing the ball to come to rest upon the lower valve seat 229. The control unit of the intermediate packer B was placed previously in the open condition illustrated in FIG. 9, so that the hydrostatic head of fluid in the well bore can now pass through the control unit, unseating the

check valve members

192, 191 and entering the cylinders 110 in order to elfect expansion of the slips 56 and packing 42 of the intermediate packer B against the wall of the well casing C.

The body member 13 of the intermediate packer does not move downwardly during its setting in the well casing, nor is the downward movement of the receptacle 17 of the intermediate packer transmitted to the upper packer A through the second tubing 250, in view of the telescopic joint 251 incorporated therein. I Fluid pressure can now be built up in the second tubular string H and in the second passages 66 of the packers and the second tubing 250 in an amount to act upon the upper piston head 174 of the upper packer control unit 126, to disrupt its shear screw 180 and shift the piston valve member 170 upwardly to the position illustrated in FIG. 9, opening the central passage 173 through this control unit, and allowing the hydrostatic head of fluid or fluid pressure developed in the second tubular string H to unseat the check valve 192 and pass to the cylinders 110 of the upper packer A, thereby effecting expansion of its slips 56 and packing assembly 42 into engagement with the wall of the well casing C. The fluid pressure in the second tubular string H can now be further increased to a value disrupting the lower shear screw 230, to eject the trip ball 156 and the tripping ball seat 229 from the member 231 into the well casing C.

Well production from the lower zone D can now pass through the tubing 254 and through the

first members

13, 29, 13 into the first tubular string G, to be conducted thereby to the top of the well bore. Well production from the intermediate zone B can now pass into the second passage 66 of the intermediate packer B, through the second tubing 250 and through the second passage 66 of the upper packer A into the second tubular string H to be conducted thereby to the top of the well bore. In the event it is desired to conduct production from the upper zone F to the top of the well bore, the sleeve valve 260 is shifted to a port opening position by suitable wire line tools (not shown), after which the passage through the second tubing 250 below the ports 253 is closed by running and latching the blanking plug 267 in position to prevent production from the intermediate zone E from passing upwardly through the packer B, second tubing 250 and upper packer A into the second tubular string H. With this condition of the apparatus, well production from the lower zone D will continue to pass upwardly into the first tubular string G, and production from the upper zone F will pass through the side ports 253 into the second tubing 250 and upwardly through the second passage 66 of the upper packer A into the second tubular string H to be conducted thereby to the top of the well bore.

If desired, the sleeve valve 260 can be reshifted to close its associated ports 253 and open the passage of the tubing 250 therebelow .so as to again secure production from the intermediate zone B, in lieu of from the upper zone F.

*If the hydraulic anchor devices 220 to 227 are used in the packers, the gripping members 222 will expand outwardly and will prevent pressure below the packers from shifting them upwardly in the well casing.

In the event it is desired to release the upper and intermediate packers A, B from the well casing, the second tubular string H can be pulled out of the upper packer receptacle 17, which will equalize the pressure across the gripping members 222, causing their springs 224 to retract them within the receptacle cylinders 220. The turning of the first tubular string 13 will disrupt the break plugs 134 in both the upper and intermediate packers A, B, allowing the pressures in the cylinders 110 on opposite sides of their pistons 111 to be equalized. The exertion of suflicient torque will also act through the mechanical advantage devices 83, to disrupt the shear rings 86 securing the first body members 13 to their hydraulic housings 67, allowing the first tubular body member in each packer to be elevated, producing elevation of the upper portions of the packers A, B with respect to their lower portions, and allowing retraction of the packing elements 46 and slips 56, permitting withdrawal of the well packers A, B from the well casing C, as well as the intervening and

lower tubings

29, 250, 254.

Each packer A, B will function individually in the same manner as it would function if disposed separately in the well bore with respect to the action of the check valve 125 in preventing bleeding of pressure from the cylinders in the event the hydrostatic head of fluid in the well bore drops below the minimum setting pressure required to maintain a packer anchored in packedotf condition in the well casing. Moreover, material diminution of the trapped pressure in the cylinders below the minimum setting pressure, as a result of rubber packlng extrusion, for example, cannot result since the energy stored in the accumulator devices 114422 will maintain the required pressure in the cylinders 110.

I claim:

1. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means responsive to the hydrostatic head of fluid in the well bore for expanding said normally retracted means outwardly; means for preventing flow of fluid from said fluid operated means upon reduction of the hydrostatic head of fluid in the well bore below the pressure in said fluid operated means; and accumulator means for maintaining the pressure in the entrapped fluid within said fluid operated means.

2. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means for expanding said normally retracted means outwardly and having a high pressure and a low pressure side; means for conducting fluid under pressure to the high pressure side of said fluid operated means to actuate said fluid I and low pressure sides of said fluid operated means to permit retraction of said normally retracted means from its outwardly expanded position.

3. In apparatus adapted to be in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means respon sive to the hydrostatic head of fluid in the well bore for expanding said normally retracted means outwardly; means for preventing flow of fluid from said fluid operated means upon reduction of the hydrostatic head of fluid in the well bore below the pressure in said fluid operated means; accumulator means for maintaining the pressure in the entrapped fluid within said fluid operated means; and means for substantially equalizing the hydrostatic head of fluid acting on said fluid operated means to permit retraction of said normally retracted means from its outwardly expanded position.

4. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means for expanding said normally retracted means outward and having a high pressure and a low pressure side; means for connecting fluid under pressure to the high pressure side of said fluid operated means to actuate said fluid operated means; means for preventing flow of fluid from said high pressure side; accumulator means for maintaining the pressure in the entrapped fluid on the high pressure side of said fluid operated means; and means operable by said body means for substantially equalizing the fluid pressure on said high and low pressure sides of said fluid operated means to permit retraction of said normally retracted means from its outwardly expanded position.

5. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means for expanding said normally retracted means outwardly and having a high pressure and a low pressure side; means for conducting fluid under pressure to the high pressure side of said fluid operated means to actuate said fluid operated means; means for preventing flow of fluid from said high pressure side; accumulator means for maintaining the pressure in the entrapped fluid on the high pressure side of said fluid operated means; initially closed means adapted to provide simultaneous communication between the fluid in the well bore and said high and low pressure sides of said fluid operated means to permit retraction of said normally retracted means from its outwardly expanded position; and means for opening said initially closed means.

6. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means for expanding said normally retracted means outwardly; means for conducting fluid under pressure to said fluid operated means to actuate the same; means for preventing flow of fluid from said fluid operated means; accumulator means for maintaining the pressure in the fluid within said fluid operated means; said accumulator means comprising a movable head having a high pressure side subject to the same fluid pressure as said fluid operated means; and yieldable means in which the full energy of said fluid pressure is storable acting on'the low pressure side of said head to resist movement of said head by said fluid pressure.

7. In apparatus adapted to beset in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means for expanding said normally retracted means outwardly; means for conducting fluid under pressure to said fluid operated means to actuate the same; means for preventing flow of fluid from said fluid operated means; accumulator means for maintaining the pressure in the fluid within said fluid operated means; said accumulator means comprising a movable head having a high pressure side subject to the same fluid pressure as said fluid operated means; and spring means in which the full energy of said fluid pressure is storable acting on the low pressure side of said head .to resist movement of said head by said fluid pressure.

8. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; fluid operated means for expanding said normally retracted means outwardly; means for conducting fluid under pressure to said fluid operated means to actuate the same; means for preventing flow of fluid from said fluid operated means; accumulator means for maintaining the pressure in the fluid within said fluid operated means; said accumulator means comprising a movable head subject to the same fluid pressure as said fluid operated means; and a plurality of coengaging conical spring washers engaging said head to resist movement of said head by said fluid pressure.

9. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; hydraulically operable means for expanding said normally retracted means outwardly comprising hydraulic cylinder means, hydraulic piston means in said cylinder means; means for conducting fluid under pressure to said cylinder means to relatively move said cylinder means and piston means and expand said normally retracted means outwardly; means for preventing flow of fluid from said cylinder means; accumulator means for maintaining the pressure in the fluid within said cylinder means, comprising a movable head having'a high pressure side subject to the same fluid pressure as said cylinder means; and yieldable means in which the full energy of said fluid pressure is storable acting on the low pressure side of said head to resist movement of said head by said fluid pressure.

iii. In apparatus adapted to be set in a well bore: body means; normally retract-ed means on said body means adapted to be expanded outwardly into engagement with the wall of the well bore; hydraulically operable means for expanding said normally retracted means outwardly com-prising hydraulic cylinder means, hydraulic piston means in said cylinder means; means for conducting fluid under pressure to said cylinder means to relatively move said cylinder means and piston means to expand said normally retracted means outwardly; means for preventing flow of fluid from said cylinder means; said cylinder means including a movable head subject to the pressure of fluid in said cylinder means; and yieldable means acting on said head to resist movement of said head by fluid pressure in said cylinder means and tending to maintain the fluid in said cylinder means under pressure.

11. In apparatus adapted to be set in a well bore: body means; normally retracted means on said body mean-s adapted to be expanded outwardly into engagement with the wall of the well bore; hydraulically operable means for expanding said normally retracted means outwardly comprising hydraulic cylinder means, hydraulic piston means in said cylinder means; means for conducting the hydrostatic head of fluid in the well bore to said cylinder means to relatively move said cylinder means and piston means to expand said normally retracted means outwardly; means for preventing flow of fluid from said cylinder means upon reduction of the hydrostatic'head of fluid in the well bore below the pressure in said cylinder