US3508610A - Retrievable well packer apparatus - Google Patents

Description

April 28, 1970 J. w. KISLING 3,508,610

RETRIEVABLE WELL PACKER APPARATUS Filed Sept. 27, 1968 2 Sheets-Sheet l (fir/77a: W. Huh/(@E' INVENTOR.

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I RETRIEVABLE WELL PACKER APPARATUS Filed Sept. 27, 1968 2 Sheets-Sheet 2 24 99 H *2; /0/ a/wreJ W. Huh/7y, E

INVEN'I'OR ATTORNEY Patented Apr. 28, 1970 3,508,610 RETRIEVABLE WELL PACKER APPARATUS James W. Kisling III, Houston, Tex., assignor to Schlumberger Technology 'Corporation, New York, N.Y., a corporation of Texas Filed Sept. 27, 1968, Ser. No. 763,150 Int. Cl. E21b 23/00 U.S. Cl. 166-120 Claims ABSTRACT OF THE DISCLOSURE The particular embodiment disclosed herein as illustrative of one form of the present invention in well packers comprises a body member and packing means for packing off a well bore, normally retracted slip means, expander means movable downwardly relative to said slip means for expanding said slip means into anchoring positions against a well conduit wall, and hydraulic means including a plurality of piston members coupled in series relationship to said expander means, each of said piston members have upper and lower pressure surfaces subject to fluid pressure in the well bore respectively below and above said packings means, so that greater fluid pressure in the well bore below said packing means than above said packing means can act on said piston members conjointly to force said expander means downwardly to retain said slip means in anchoring nnsitions against the well conduit wall.

This invention relates generally to well tools used for packing off or isolating well bore zones, and more specifically to retrieva'ble well packers and plugs having expansible anchors and packing for preventing fluid movement in either direction past its sealing point.

To conduct testing, remedial, stimulation or production operations in a particular zone in a well, the zone can be isolated by well tools which can be positioned in the well bore below and above the zone. The lower tool, com monly called a bridge plug, functions to seal off the entire cross-section of the well bore to isolate the zone from fluids at their hydrostatic pressures which are below the zone. The upper tool, commonly called a packer, is generally retrievalble and functions to seal otf the annulus between a tubing string attached to the packer and the well casing to isolate the zone from fluids at their hydrostatic pressures which are above the zone. The tubing string provides a means of access to the isolated zone for fluid flow, testing tools, or other instruments which can be lowered therethrough. Although permanent type bridge plugs have been used for the lower tool, it has become common practice to use retrievable type bridge plugs which can be left in the well bore if desired, but which can also be retrieved to the surface for further and repeated usage if desired.

Inasmuch as fluid pressure may be imposed on a bridge plug either from above or below, it is necessary to anchor the plug against movement in both directions. In the past, such anchoring has been accomplished for the most part by independently operable slips and expanders, one Slip and expander combination being arranged to prevent movement in one direction and the other slip and expander combination coming into play to prevent movement in the other direction. A more recent advance in the art, shown in the 196869 Composite Catalog of Oil Field Equipment and Services, page 2755, enables only a single slip and expander combination to prevent movement in both directions. This slip and expander combination is mechanically set against movement in a downward direction, and a hydraulic system including a piston on the expander which is responsive to greater fluid pressure below the plug functions to hold the slips in set position, thereby preventing upward movement.

It is necessary, in order to provide adequate retaining force to the slips when the fluid pressure in the well bore below the packer is greater, for the hydraulic system to have ample pressure areas on which the greater fluid pressure can act, because it will be appreciated by those skilled in the art that the downward force on the expander is a function of the pressure differential across the tool and the pressure area of the piston. One solution to the problem of adequate pressure areas is disclosed in U.S. Patent No. 3,437,136 to Young, assigned to the assignee of the present invention, wherein the body structure of the packer has different diameter sections, the packing elements being mounted on the larger diameter section and the piston being sealingly slidable on the smaller diameter section. This arrangement enables the piston to have an increased transverse area which is acted upon by the greater fluid pressure in the well bore below the packing elements, resulting in an adequate downward force on the expander over a range of sizes of tools.

The present invention is directed to the same problem of providing adequate pressure areas for the piston, and according to the concepts of the present invention, the hydraulic system includes a plurality of piston members which are coupled in series relationship to the expander. Each of the piston members has an upwardly facing presssure surface which is subject to fluid pressure in the well bore below the packing elements, and a downwardly facing pressure surface which is subject to fluid pressure in the well bore above the packing elements. Each of the piston members can be sealingly slidable on the same diametered portion of the body structure, and the downward force on the expander due to greater fluid pressure below the packing elements is amplified according to the number of piston members used. The present invention thus enables selectivity of cone-holding response to provide adequate retaining force on the slips over a wide range of easing sizes and tools.

The novel features of the present invention are set forth with particularity in the appended claims. The invention, together with other concepts and advantages thereof, may be best understood by way of example of one embodiment thereof when taken in conjunction with the following drawings in which:

FIGURE 1A is a sectional view of the upper portion of an apparatus in accordance with the present invention with parts in relative positions for longitudinal movement in a well conduit;

FIGURE 1B is a view similar to FIGURE 1A showing the lower portion of the apparatus of the present invention and forms a lower continuation of FIGURE 1A;

FIGURE 2A is a sectional view similar to FIGURE 1A but with parts in their relative positions when the apparatus is set in a well conduit; and

FIGURE 2B is the lower continuation of FIGURE 2A.

In order to conduct remedia, stimulation or production operations in a cased well bore which traverses a formation, it may be necessary to isolate a zone of the well bore adjacent the formation. This can be accomplished by upper and lower packers releasably connected together by a running tool and lowered into the well bore on a pipe string. The lower packer is set to plug the well bore at the lower end of the zone. Then the running tool is released from the lower packer and the upper packer is elevated and set at the upper end of the zone. The pipe string provides a passageway from the earths surface through the upper packer and into the zone for fluid flow as well as various wireline or other tools. When the operation is completed,

3 the upper packer can be released and reconnected to the lower packer, which is then released so that both packers can be withdrawn from the well or moved to another location in the well bore. The upper packer can be constructed according to teachings of McGill, Patent No. 3,399,729, dated Sept. 3, 1968.

Referring now to FIGURES 1A and 1B for details of the lower packer, commonly called a retrievable bridge plug, apparatus in accordance with the present inventioin includes a generally tubular body member or mandrel extending throughout the length of the tool. The body member 10 has a central bore 11 which is opened at its lower end by several side ports 12. The upper end of the body member 10 is closed by a threadedly attached connector head 13 having J-slots 14 or the like in its outer periphery for connecting to a conventional running and retrieving tool (not shown).

A plurality of bypass ports 15 extend laterally through the wall of the body member 10 below the connector head 13. Sealing elements 16 and 17 are received in annular grooves above and below the ports 15. A sleeve valve 18 is slidably disposed on the body member 10 adjacent the ports 15 and is movable between a lower position as shown in FIGURE 1A where the bypass ports 15 are open, and an upper position where the upper end of the sleeve valve 18 abuts the lower end of the connector head 13. In the upper position, the sleeve valve 18 spans the ports 15 and, in combinaiton with the sealing elements 16 and 17, functions to block fluid flow therethrough. A plurality of spring fingers 19 extend from the lower end of the sleeve valve 18 and have enlarged head portions 20 which are sized to engage an annular shoulder 21 formed on the body member to releasably hold the valve sleeve in either open or closed position.

The body member 10 carries a generally tubular compression sleeve 24 which has a downwardly facing shoulder or abutment 25. The abutment 25 engages the upper end of a packing structure 26 which can be formed by a plurality of elastomeric rings 27 which are adapted, when compressed, to be expanded into sealing contact with the well bore wall in a typical manner. The inner wall surface of the compression sleeve 24 is spaced laterally away from the outer periphery of the body member 10 to provide an annular fluid passageway 28. A suitable bearing 29 is mounted between an upwardly facing shoulder 30 on the compression sleeve 24 and a downwardly facing shoulder 31 on the body member 10 to reduce frictional resistance to rotation of the body member within the compression sleeve underloaded conditions. The passageway 28 is continued past the bearing 29 by one or more radially cut and vertically disposed grooves 32. Coupled to the upper end of the compression sleeve 24 is a sleeve extension 33 having an inwardly extending shoulder 34 carrying a seal ring 35, which is sealed against the periphery of the body member 10. An inner sleeve 36 is positioned within the extension 33 and has an annular portion 37 which is sealed against the extension by a seal ring 38. Upper and lower ports 39 and 40 in the inner sleeve 36 and the extension 33, respectively, are provided to communicate the vertical space 41 with the passageway 28 and with the well annulus above the packing structure 26. Thus, it will be apparent that the passageway 28 is always in communication with fluids in the well annulus, and serves as a transmitting channel for the pressure of fluids in the well bore above the packing structure.

An expander cone 45 (FIGURE 1B) is mounted on the lower portion of the body member 10 and has outer surfaces 46 inclining downwardly and inwardly toward the body member. Coupled between the expander cone 45 and the packing structure 26 is a hydraulic assembly 47 including a sleeve structure 48 extending upwardly from the expander cone and coupled at its upper end to an inwardly extending piston member 49 which is slidable on the lower portion 50 of the compression sleeve 24 and sealed with respect thereto by a seal ring 51. Another piston member 42 is formed on the sleeve structure 48 intermediate its ends and also extends inwardly in sealing and sliding contact with the lower portion 50 of the compression sleeve, fluid leakage being prevented by a seal ring 53. An annular floating piston member 55 is movable between the body member 10 and the sleeve structure 48 between an upper position against an outwardly extending stop shoulder 56 on the body member, and a lower position where it rests on the expander cone 45. Appropriate O-rings or other seals 57 and 58 seal between the floating piston member 55 and adjacent wall surfaces to prevent fluid leakage past the piston member.

The upper piston member 49 can engage above splines 59 on the compression sleeve 24, such engagement limiting downward movement of the sleeve structure 48 and the expander cone 45 relative to the body member 10, and the splines 59 engaging complementary splines 60 on the piston member 49 to prevent relative rotation between the compression sleeve 24 and the sleeve structure 48. The piston member 49 supports a gauge ring 61 which provides an upwardly facing abutment engaging the lower end of the packing 26. The gauge ring and piston member may be coupled against relative rotation by radially extending grooves and projections 62 and 63 which also provide a fluid path to the upper end surfaces of the piston member 49.

The lower portion 50 of the compression sleeve 24 extends downwardly to a location adjacent the upper surface of the stop shoulder 56 on the body member 10. A separator piston 65 on the compression sleeve 24 is sealed against the inner periphery of the sleeve structure 48 by a seal ring 66, the piston 65 being located between the hydraulic piston members 49 and 52. A port 67 communicates the upper face 68 of the lower piston member 52 with the well fluids in the annulus below the packing 26, and as previously described, the upper surfaces of the upper piston member 49 are also subject to fluid pressure in the well bore below the packing elements. Moreover, the passageway 28 between the compression sleeve 24 and the body member 10 is in communication with the chamber 69 formed between the lower piston member 52 and the floating piston member 55, and via a port 70 with the chamber 71 formed between the upper piston member 49 and the separator piston 65. Thus, it will be appreciated that the respective lower faces 72 and 73 of the upper piston member 49 and the lower piston member 52 are in fluid communication with the well annulus above the packing 26 via the passageways 28 and 41 and the various ports 39, 40 and 70.

A cage member is movably mounted on the lower end portion of the body member 10 above a stop flange 81. The cage member 80 has radially directed recesses receiving circumferentially spaced drag blocks 82 which are urged outwardly by coil spring 83 into frictional contact with the well casing. A plurality of wickered slip elements 84 can be pivotally coupled to the upper end of the cage member 80 by reins 85 or the like, and are arranged for lateral movement between retracted and expanded positions. The slip elements 84 have inner inclined surfaces 86 which slidably engage the outer inclined surfaces 46 on the expander cone 45, and the slip elements can be slidably coupled to the expander cone by a conventional dove-tail tongue and groove connection 87.

A clutch assembly 90 is provided for controlling relative longitudinal movement between the cage member 80 and the body member 10. The clutch assembly 90 includes a segmental clutch nut 91 which is received within an internal annular recess 92 in the cage member, each of the nut segments being secured against rotation relative to the cage member by lugs 93 which engage in peripheral slots in the segments. Upper and lower band springs 94 and 95 permit lateral movement of the nut segments while continuously urging the segments toward contracted positions around the body member 10. Each nut segment can have upper left-hand threads 96 and lower right-hand threads 97 which are cooperable with companion threads 98 and 99 on the body section 26 to secure the body member relative to the cage member in spaced longitudinal positions. An inwardly biased stop lug 100 can initially engage within a shouldered recess 101 in the mandrel to prevent counter-clockwise rotation of the cage member 80 relative to the body member during lowering, thereby preventing rotational locking of the lower end surface of the cage member against the upper face of the gauge stop ring 81.

In operation, the parts can be assembled as shown in FIGURES 1A and 1B and lowered in the well casing to a location where it is desired to form a pressure bridge, for example, at the lower end of a zone to be pressurized. During lowering, a tubing string is connected to the connector head 13 by a suitable running tool (not shown), andthe sleeve valve 18 is in its lower position where the bypass ports 15 are open. Thus, fluids in the well bore can bypass through the tool via the lower ports 12, the body bore 11 and the bypass ports 15, as well as around the packing structure 26 to provide ample bypass area. During lowering, the lower threads 97 of the segmented clutch nut 91 are in engagement with the lower body threads 99 to prevent upward movement of the cage member 80 relative to the body member 10. The slip segments 84 are thus held in retracted positions and cannot move upwardly to be shifted outwardly by the expander cone 45. The packing structure 26 is, of course, retracted.

At setting depth, the tool is halted and the body member is torqued or turned several turns to the right by rotation of the tubing string. Inasmuch as the cage member 80 will not rotate due to frictional engagement of the drag blocks 82 with the casing, rotation of the body member 10 will release the clutch nut threads 97 from the body threads 99 to enable downward movement of the body member 10. Downward movement of the body member 10 by lowering the pipe string will cause the compression sleeve 24, the packing structure 26 and the hydraulic assembly 47 to move downwardly, thereby bringing the expander cone 45 behind the slip elements 84 and shifting the slip elements into gripping engagement with the well casing wall as shown in FIGURE 2B. The drag blocks 82 support the cage member 80 and the slips 84 against downward movement.

When, the slip teeth 102 are firmly engaged, the expander cone 45 and hydraulic assembly 47 are supported against further downward movement, thereby preventing further downward movement of the lower gauge ring or abutment 61. Accordingly, the weight of the tubing string can be imposed on the body member 10, causing downward movement of the compression sleeve 24 and compression of the packing structure 26 between the upper abutment 25 and the lower abutment 61. Compression of the packing structure will effect expansion of the elements 27 into sealing engagement with the casing wall. As the body member 10 moves downwardly relative to the cage member 80, the upper body threads 98 can ratchet through the upper clutch nut threads 96 which will trap the body member in the lowermost position to which it is moved to lock the compression energy in the packing structure 26 and the slips '84 in set positions. The running tool can be released in a conventional manner which results in shifting the valve sleeve 18 upwardly to its closed position spanning the ports 15. The tool is now set to hold pressure in either direction.

If a greater fluid pressure exists in the well bore above the tool, the slips 84 will be set even tighter against movement. Further, if a greater fluid pressure exists in the well bore below the tool, the greater fluid pressure acts downwardly on the upper faces of the upper and lower piston members 49 and 42, while the lesser fluid pressure above the tool is channeled to the lower faces 72 and 73 of the piston members. As a consequence, the expander cone 45 is forced downwardly relative to the slips 84 to retain them in gripping contact with the casing. The upward force on the floating piston 55 and the separator piston 65 is transferred by the body member 10, the clutch nut 91 and the cage member to the slips 84 which are gripping the casing. Thus, the tool will not move in either direction in the well bore when fluid pressure is imposed upon it.

When it is desired to either retrieve the tool or to move to another setting location, the tubing string is lowered to engage the running tool with the connector head 13. The sleeve valve 18 is automatically pushed to its lower position where the bypass ports 15 are open to equalized fluid pressures across the packing structure 26. To release the slips 84 and the packing 26, the body member 10 is rotated several turns to the right to release the upper clutch nut threads 96 from engagement with the body threads 98. Then the body member is pulled upwardly to relieve the compression on the packing structure 26 so that the rings 27 will inherently retract. The splines 59 on the compression sleeve 24 will engage the piston member 49 to pull the expander cone 45 from behind the sli elements 84, thereby permitting their retraction. As the body member 10 reaches the upper limit of its travel relative to the cage member 80, the lower body threads 99 will ratchet into the lower clutch nut threads 97 to lock the cage member 80 against movement relative to the body member 10. The packer is then free to be moved longitudinally in the well bore in either direction.

A new and improved well packer has been disclosed which can be anchored against movement in either direction in a well bore. The packer includes a hydraulic structure for applying a holding force to the slips in response to greater fluid pressure in the well bore below the packer, the hydraulic structure including a plurality of piston members coupled in series relationship to the expander cone, each piston member having upper and lower pressure surfaces which are subject to fluid pressure in the well bore respectively below and above the packing elements. Accordingly, a greater well bore pressure below the packing than above the packing will act to force the expander downwardly to retain the slips set against movement in the casing. Although in the embodiment shown in the drawing two piston members are shown, it will be apparent that more than two piston members could be used to amplify the downward force on the expander cone even greater.

Since certain changes and modifications may be made in the present invention by those skilled in the art without departing from the invention concepts involved, it is the aim of the appended claims to cover all changes and modifications falling within the true spirit and scope of the present invention.

I claim:

1. A well packer apparatus comprising: a body structure having packing means thereon for packing off the cross-section of a well bore; normally retracted slip means; expander means movable downwardly relative to said slip means for expanding said slip means into gripping contact with the well bore wall; and hydraulic means including a plurality of piston members coupled in series relationship to said expander means, each of said piston members having an upwardly facing pressure surface subject to fluid pressure in the well bore below said packing means and a downwardly facing pressure surface subject to fluid pressure in the well bore above said packing means, so that greater fluid pressure in the well bore below said packing means than above said packing means acts on said piston members conjointly to force said expander means downwardly to retain said slip means in gripping contact with the well bore wall.

2. A well packer apparatus comprising: a body structure; normally retracted pacing means on said body structure adapted to be expanded in sealing contact with a well bore wall; normally retracted slip means; expander means movable downwardly relative to said slip means for expanding said slip means into gripping contact with a well bore wall; releasable means for securing said packing means and said slip means in expanded positions; and hydraulic means responsive to greater fluid pressure in the well bore below said packing means for forcing said expander means downwardly relative to said slip means to retain said slip means in gripping contact with a well bore wall, said hydraulic means including a plurality of piston members coupled in series relationship, each of said piston members having an upwardly facing transverse surface subject to fluid pressure in the well bore below said packing means and a downwardly facing transverse surface subject to fluid pressure in the Well bore above said packing means.

3. The well packer apparatus of claim 2 wherein said hydraulic means further includes a sleeve structure extending upwardly from said expander means, each of said piston members being integral with said sleeve structure and extending inwardly in sealing and sliding contact with the outer periphery of said body structure.

4. The well packer apparatus of claim 3 wherein said sleeve structure has port means for feeding fluid in the well bore below said packing means to one of said upwardly facing transverse surfaces of said piston members.

5. The well packer apparatus of claim 4 further including passage means for feeding fluid in the well bore below said packing means to the other of said upwardly facing transverse surfaces of said piston members.

6. A well packer apparatus comprising: a body member adapted to be releasably coupled to a running-in string; a sleeve structure surrounding a portion of said body member, said sleeve structure and body member providing a fluid passageway therebetween; normally retracted packing means on said sleeve structure adapted to be expanded into sealing contact with a well bore wall, said fluid passageway being in communication with the well bore above said packing means; normally retracted slip means; expander means movable downwardly relative to said slip means for expanding said slip means outwardly into gripping engagement with a well bore wall; releasable means responsive to manipulaion of the running-in string for securing said packing means and slip means in retracted and expanded positions; a plurality of pressure responsive piston members sealingly slidable on said sleeve structure; and means for coupling said piston members to said expander cone in conjoii t force transmitting relationship thereto, each of said piston members having upwardly facing pressure surfaces subject to fluid pressure in the well bore below said packing means and downwardly facing pressure surfaces in communication with said passageway, so that said downwardly facing surfaces are subject to fluid pressure in the Well bore above said packing means, whereby a greater fluid pressure in the well bore below said packing meaps than above said packing means forces said expander means downwardly with a force which is multiplied by the number of said piston members.

7. The well packer apparatus of claim 6 wherein said piston members and said packing means are mounted on a same diametered portion of said sleeve structure.

8. The well packer apparatus of claim 6 wherein said body member has a fluid bypass passage therein; and valve means for opening and closing said bypass passageway.

9. The well packer apparatus of claim 6 further including transverse members located below each of said piston members and sealed with respect to said coupling means for preventing fluid communication between said downwardly facing pressure surfaces and the well bore below said packing means.

10. The well packer apparatus of claim 9 wherein one of said transverse members is mounted on said sleeve structure and the other of said transverse members is mounted on said body member.

References Cited UNITED STATES PATENTS 3,233,675 2/1966 Tamplen et al. l66, 3,288,219 11/1966 Young et a1. 166-120 3,338,308 8/1967 Elliston et al. 16612O 3,361,207 1/1968 Chenowcth 166 -120 3,399,729 9/1968 McGill 166120 3,412,801 1l/1968 Young 166-120 3,412,802 11/1968 Kisling 166l20 3,426,846 2/1969 Young 166--l20 X 3,437,136 4/1969 Young 166l20 DAVID H. BROWN, Primary Examiner US. Cl. X.R. 166-133,

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