US3306361A

US3306361A - Double set hydraulic anchor

Info

Publication number: US3306361A
Application number: US374430A
Authority: US
Inventors: Maurice P Lebourg
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1964-06-11
Filing date: 1964-06-11
Publication date: 1967-02-28
Anticipated expiration: 1984-02-28

Description

Feb. 28, 1967 M. P. LEBOURG DOUBLE SET HYDRAULIC ANCHOR 2 Sheets-Sheet 1 Filed June 11, 1964 Mawvre [960 0/9 IN V EN TOR.

ZMXQM ATTOR/Vf) Feb. 28, 1967 M. P. LEBOURG DOUBLE SET HYDRAULIC ANCHOR 2 Sheets-Sheet 2 Filed June 11, 1964 May/v06 P. leau/y INVENTOR.

3,306,361 DGUBLE SET HYDRAULIC ANCHOR Maurice P. Lebourg, Houston, Tex., assignor, by mesne assignments, to Schiumherger Technology Corporation, Houston, Tex.. a corporation of Texas Filed June 11, 1964, Ser. No. 374,430 13 Claims. (Cl. 166-122) This invention relates to apparatus adapted for anchoring a well tool in place within a well bore; and, more particularly, to hydraulically actuated anchors which, when set in place, will be secured against hydraulic pressures in the well acting from either direction by an anchoring force proportionately related to the acting pressure.

In conducting such well-completion operations as acidizing, cementing, or fracturing, a full-opening well packer dependently coupled from a tubing string is positioned at a particular depth in a cased well and the packer set to isolate the formation interval to be treated from the remainder of the well bore thereabove. Treating fluids are then pumped downwardly at high pressure through the tubing and full-bore packer and introduced into the formation being treated through perforations appropriately located in the casing.

It will be appreciated that such full-bore packers must be capable of withstanding high pressures acting from either direction. Furthermore, during the course of typical completion operations, the packer can be subjected to high pressures acting alternately from both and above and below the packer. Accordingly, it is necessary to securely anchor the packer against movement in either longitudinal direction.

Heretofore, extendible slip members have typically been employed to anchor such packers against movement in at least one direction. Extendible anchoring members have also been developed which are hydraulically actuated by the fiuid being pumped through the tubing and secure the apparatus against shifting.

Accordingly, it is an object of the present invention to provide new and improved anchoring apparatus for well packers, which apparatus has hydraulically actuated wallengaging members which are pressed into anchoring engagement with a force proportionately related to the pressure of fluids in the well.

It is an additional object of the present invention to provide new and improved well tool anchors which will anchor the tools in response to a pressure differential acting from either direction.

Anchoring apparatus arranged in accordance with the present invention includes a selectively operable hydraulic system responsive to fluid pressure in a well and adapted to maintain wall-engaging means in anchoring engagement with a force proportionately related to a fluid pressure differential across the apparatus.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view of a full-bore packer having an anchor thereon employing principles of the present invention and depicted as they would appear within a well bore;

FIG. 2 is a detailed cross-sectional View of an embodiment of an anchor;

FIG. 3 is a cross-sectional view taken along .the line 33 of FIG. 2;

FIG. 4 is a schematic representation of a portion of the anchor shown in FIG. 2; and

FIG. Sis a view of an alternate embodiment of an anchor.

nited States Patent Fice As seen in FIG. 1, a typical full-bore packer 10 is dependently connected in a tubing string 11 and positioned within a well bore 12 having a casing 13 set therein. An anchor 14 incorporating principles of the present invention is serially coupled between the upper end of the tubular body member or mandrel 15 of the full-bore packer 10 and the lower end of a conventionally arranged bypass valve 16, which is in turn connected to the lower end of the tubing string 11. As is conventional in the art, such a bypass valve 16 is opened whenever the fullbore packer 111 is being shifted Within a fluid-filled well to divert some of the fluids through the central bore 17 ofv the mandrel 15 and bypass valve before returning to the annulus of the well bore 12. Whenever the packer 10 has been set in position, the bypass valve 16 is of course closed to prevent fluid communication through the mandrel bore 17 of the sealingly engaged packer 10.

The typical full-bore packer 10 illustrated in FIG. 1 includes a rotatable tubular body member or mandrel 15 slidably disposed within and extended through a tubular housing member 18. Elastomeric packing means 19 are mounted around the upper portion of the housing 18 intermediate an outwardly directed shoulder on the mandrel 15 and a slidably disposed slip bowl 20. Normally retracted slip members 21 are operatively mounted around the upper end of the housing 18 and cooperatively engaged with the slip bowl 20 in the well-known manner. Conventional drag blocks 22 are provided to secure the housing 18 to the casing 13 as the mandrel 15 is manipulated relative to the housing to extend the packing means 19 and slips 21 against the casing. Conventionally arranged I-slots and J-pins (not shown) selectively latch the mandrel 15 relative to the housing 18 to keep the packer 10 retracted.

Accordingly, when the packer 10 is to be set, the tubing string 11 is picked up slightly and then manipulated in a particular manner to free the mandrel 15 for downward travel. As the mandrel 15 is lowered, the drag blocks 22 restrain the housing 18 as the downward movement of the mandrel successively drives the slip bowl 20 downwardly to extend the slips 21 and foreshorten the packing means 19 in the well-known manner. By the time the mandrel 15 has reached its lower limit of travel, the slips 21 will be engaged against the casing 13 and the packing means 19 displaced into sealing engagement there-' with. It will be appreciated, of course, that once set, the slips 21 will then prevent the full-bore packer 10 from moving further downwardly within the casing 13.

As seen in FIG. 1, the hydraulic anchor 14 is dependently coupled in the tubing string 11 to the upper end of the packer mandrel 15. A self-contained hydraulic system therein is adapted to operatively actuate the anchor 14 in response to a pressure differential across the packing means 19. Thus, whenever the bypass valve 16 is closed after the packing means 19 has been set, the anchor 14 will be anchoringly engaged to secure the mandrel 15 in its lower position as well as to prevent the packer 10 from shifting upwardly.

Turning now to FIG. 2, the anchor 14 includes a tubular housing 23 having a longitudinal bore 24 of a uniform diameter extending therethrough. This longitudinal bore 24 is of course in fluid communication at all times with the central bore 17 of the packer mandrel 15. Mounted around the anchor housing 23 is an expansible elastomeric sleeve 25 encircling the housing with a plurality of elongated casing-

engaging members

26, 27 being mounted uniformly around the periphery of the sleeve. The enlarged upper 28 and lower 29 ends of the elastomeric sleeve 25 are sealingly secured within opposed peripheral recesses 31), 31 around the housing 23 to provide a fluidtight space 32 between the sleeve and housing,

Each of the casing-

engaging members

26, 27 is elongated and has a thick, arcuate, cross-section (FIG. 3). Alternate ones 26 of these casing-engaging members are centrally aligned and mounted along the outer convex surface of relatively thin, elongated, arcuate backing members 33. A sufficient number of these mounted members 26 are disposed uniformly around the periphery of the elastomeric sleeve 25 that the backing members 33 substantially encompass the sleeve. The remaining unmounted casing-engaging members 27 are alternately disposed between the mounted casing-engaging members 26 in such a manner that the unmounted members 27 straddle adjacent backing members 33 and cover the gap 34 therebetween.

The ends of the casing-engaging

members

26, 27 are beveled, as at 35 (FIG. 2), for reception within the opposed

annular housing recesses

30, 31. Springs 36, 37 operatively engaged at opposite ends of the

members

26, 27 bias the members inwardly. It will be appreciated, therefore, that although the casing-

engaging members

26, 27 will be moved radially outwardly against

springs

36, 37 whenever the elastomeric sleeve 25 is inflated, the beveled ends of the members cannot escape from the

housing recesses

30, 31.

Turning now to the hydraulic system of the anchor 14, the housing 23 is formed in such a manner as to provide a first annular chamber 38 of a particular cross-sectional area in the housing and a second annular chamber 39 of a smaller cross-sectional area immediately thereabove and in coaxial alignment therewith. Radial ports 40 at the junction of the

annular chambers

38, 39 provide fluid communication therefrom to the inner bore 24 of the anchor 23. A second group of ports 41 is provided to establish fluid communication from outside of the housing 23 into the lower portion of the lower annular chamber 38. A fluid passage 42 within the housing 23 extending from the upper portion of the upper annular cham ber 39 is divided into separate branches 43, 44 (FIG. 4), each of which lead into a valve chamber 45 thereabove. A second fluid passage 46 leads from the valve chamber 45 to the fluid-tight space 32 beneath the elastomeric sleeve 25.

A complementarily formed annular piston member 47 is slidably disposed within the lower annular chamber 38 and fluidly sealed therein with respect to the housing 23 by O-

rings

48, 49. An elongated tubular piston member 50 is complementarily fitted and slidably disposed within the upper annular chamber 39 and fluidly sealed therein relative to the housing 23 by O-

rings

51, 52. A compression spring 53 within the upper piston chamber 39 is engaged between a downwardly directed housing shoulder 54 and the upper face 55 of the tubular piston member 50. This spring 53 biases the tubular piston member 50 downwardly so that its lower face 56 will normally rest upon the upper face 57 of the annular piston member 47 and urge that piston downwardly as well until its lower face 58 comes to rest on the bottom of chamber 38.

It will be appreciated that when the upper piston chamber 39, valve chamber 45, fluid passages 42-44, 46 and the fluid-tight space 32 are filled with a suitable hydraulic fluid, a hydraulic pressure will be developed within this system whenever the tubular piston member 50 is advanced further upwardly into the upper piston chamber 39 as. shown in FIG. 2. Furthermore, whenever a hydraulic pressure is so developed, the elastomeric sleeve 25 will be inflated and press the casing-engaging

members

26, 27 against the casing.

Whenever the packer and its cooperatively arranged anchor 14 are positioned in a fluid-filled well bore and the packing means 19 set, the pressure of the fluids above the packing means will be transmitted through the outer fluid ports 41 through the anchor housing 23 against the lower face 58 of the annular piston member 47 as well as act on the outside of the elastomeric sleeve 25. The

pressure from below the packing means 19 will be transmitted through the open mandrel bore 17 into the inner bore 24 of the anchor 14 and be directed through inner ports 49 simultaneously against the upper face 57 of the annular piston member 47 and the lower face 56 of the tubular piston member 50. Thus, it will be appreciated that the piston members 47, will shift within their

respective chambers

38, 39 in response to a pressure differential across the engaged packing means 19.

To illustrate the operation of the anchor 14 and its hydraulic system, assume first that the pressure of the fluids in the well below the set packing means 19 is greater than the pressure of the fluids thereabove. In this instance, the pressure that is communicated through the mandrel bore 17 to within the inner bore 24 of the anchor 14 will be greater than that outside of the anchor. The annular piston member 47 will be driven downwardly since the pressure acting on its upper face 57 is greater than that acting on its lower face 58. This greater pressure acting on the lower face 56 of the tubular piston member 50 of course advances the piston further upwardly into the upper piston chamber 39 to displace fluid upwardly and develop a hydraulic pressure within the fluid-filled hydraulic system. The pressure so developed will of course be substantially equal to the greater pressure within the anchors inner bore 24. Since the hydraulic pressure inside of the sleeve 25 is greater than the pressure of the fluids in the well bore outside of the elastomeric sleeve, the sleeve will be inflated. It will be appreciated, therefore, that the wall-engaging

members

26, 27 will be pressed against the casing with a force proportionately related to the pressure differential across the set packing means 19 of the fluids in the well.

Should, however, the conditions within the well be reversed and the pressure of the fluids in the well above the packing means 19 instead be greater than that of those below, this higher fluid pressure will act through the outer ports 41 to shift the annular piston member 47 upwardly. Since the lower face 56 of the tubular piston member 50 normally rests on the annular piston 47, as the annular piston member 47 is shifted upwardly, the tubular piston is advanced upwardly to develop pressure within the fluid-filled hydraulic system. The pressure so developed, however, will be proportionately greater than the pressure of the fluids in the well bore above the packing means 19 as determined by the ratio of the effective cross-sectional area of the annular piston member 47 divided by the effective cross-sectional area of the tubular piston member 50. It is, of course, necessary in this instance that the developed hydraulic pressure be greater than the pressure of the fluids above the packing means 19 inasmuch as this latter pressure is not only the actuating pressure but is also being applied against the outside of the elastomeric sleeve 25. Thus, the casing-engaging

members

26, 27 will again be pressed against the casing with a force proportionately related to the pressure differential across the set packing means 19 of the fluids in the well.

In either of the two above-described conditions, it will be realized that the casing-engaging

members

26, 27 will remain engaged with the casing only so long as the packing means 19 is set to maintain a pressure differential on opposite sides thereof. Thus, whenever the packing means 19 is released, the pressure differential will no longer exist and the anchor 14 will automatically retract as the spring 53 returns the tubular piston member 50 to its initial position as the sleeve 25 deflates.

Whenever the retracted full-bore packer 10 is being moved through a fluid-filled well bore, it is not at all unusual for the restriction to passage of fluids around the packer to create a slight pressure differential between the outside of the packer and its mandrel bore 17. For example, as the package 10 is being pulled upwardly, the fluid pressure outside of the anchor 14 above the packing means 19 will be somewhat greater than that below the packing means and in the mandrel bore 17. This pressure differential could of course become sufficiently great that both

piston members

47, 50 would shift upwardly and extend the casing-engaging

members

26, 27 against the casing to retard, if not prevent, the packer from moving further.

Accordingly, to prevent premature actuation of the anchor 14, a conventional spring-loaded, normally-closed, check valve 59 (FIGS. 2A and 4) is connected in series between the upper piston chamber 39 and the fluid-tight space 32 beneath the elastomeric sleeve 25. The valve 59 is disposed in the valve chamber 45 with its inlet connected to one 43 of the branch portions of the lower fluid passage 42 and its outlet open to the valve chamber. This valve 59 is biased to remain closed until the pressure in the upper piston chamber 39 exceeds that in the fluidtight space 32 by a predetermined differential. Thus, the elastomeric sleeve 25 will not be inflated until a substantial hydraulic pressure is developed in the upper piston chamber 39.

The other conventional check valve 60 (behind valve 59 in FIG. 2) disposed within the valve chamber 45 has its inlet open to the valve chamber and its outlet connected to the other branch portion 44 of the lower fluid passage 42. Although it is in parallel with the springloaded valve 59, this check valve 60 operates in the opposite direction and opens only when the pressure in the valve chamber 45 exceeds that in the lower fluid passage 42. Thus, this valve 60 opens only to allow hydraulic fluid to return to the upper piston chamber 39 as the elastomeric sleeve 25 contracts and the tubular piston member 50 returns to its normal position.

Thus, whenever the tubular piston 50 inadvertently shifts upwardly in response to a pressure differential across the packing means 19 as the retracted packer 10 is moved through a well bore, the hydraulic presssure so developed is insufilcient to overcome the bias holding the spring-loaded valve 59 closed. The other valve 60 of course remains closed as well.

When the packing means 19 is set, the hydraulic pressure developed in the upper piston chamber 39 must of course be suflicient to overcome the bias and open the valve 59 before hydraulic pressure can buildup in the remainder of the system. When, however, the springloaded valve 59 does open, the pressure in the valve chamber 45 will of course be lower than that in the upper piston chamber 39 by an amount proportionate to the bias on the valve. Thus, the pressure diflerential will hold the other check valve 60 closed so long as the tubular piston 50 is being urged upwardly into the upper piston chamber 39. This other check valve 60 will of course open whenever the hydraulic pressure within the upper piston chamber 39 drops below that in the valve chamber 45. Thus, whenever the packing means 19 is released and the pressure of the fluids in the well is equalized across the packing means, the elastomeric sleeve 25 will contract and displace hydraulic fluids downwardly through the opened check valve 60 and back into the upper piston chamber 39 as the spring 53 returns the tubular piston 50 to its normal position.

Turning now to FIG. 5, the anchor 100 includes a tubular housing 101 having a central axial bore 102 of uniform diameter extending therethrough. At a central portion of the housing 101 a plurality of outwardly facing piston members 103 are operatively mounted within radial bores 104 and fluidly sealed therein by O-rings 105. Leaf springs 106 fastened to the housing 101 are arranged to retain the piston members 103 and to bias the piston members inwardly whenever they are extended. The outer face of each piston member 103 is serrated to provide casing-engaging teeth or wickers 107.

The inner end of each of the radial bores 104 opens to a fluid-tight space 108 which extends above and below the casing-engaging piston members 103. At the open upper end of this fluid-tight space 108, an annular cham- 0 her 109 is formed in the housing 101. Similarly, at the open lower end of the fluid-tight space 108, a second annular chamber 110 is formed in the housing 101.

The upper annular chamber 109 is formed into an enlarged upper portion 111 and a lower portion 112 of a smaller cross-sectional area. An annular piston member 113 having an enlarged upper portion 114 and a reduced diameter lower portion 115 is complementarily formed and slidably disposed within the upper annular chamber 109 and fluidly sealed therein by O-rings 115- 118. An outer port 119 through the housing 101 provides fluid communication from the exterior of the anchor to the upper face 120 of the enlarged piston portion 114. An inner port 121 provides fluid communication from the inner bore 102 of the housing 101 to the lower face 122 of the enlarged portion 114 of the annular piston member 113. A compression spring 123 is disposed between the lower end 124 of the piston member 113 and an upwardly directed housing shoulder 125.

A complementarily formed annular piston member 126 is slidably disposed within the lower annular chamber and fluidly sealed therein by O-

rings

127, 128 mounted around its outer and inner surfaces. An inner port 129 provides fluid communication from the inner bore 102 of the housing 101 to the lower face 130 of the annular piston member 126.

Thus, it will be appreciated that with the upper annular chamber 109, the lower annular chamber 110, the fluidtight space 108 and that portion of the bores 104 beneath the casing-engaging piston members 103 being filled with a suitable hydraulic fluid, a hydraulic pressure will be developed Within the system whenever either

piston member

113, 126 is advanced toward the casing-engaging members 103. It is to be understoood, of course, that whenever such a hydraulic pressure is so developed, the casingengaging piston members 103 will be forced outwardly to press the casing-engaging teeth 107 against the casing.

To illustrate the operation of the anchor 100 and its hydraulic system, assume first that the pressure of the fluids in the well beneath the set packing means therebelow is greater than the pressure of the fluids thereabove. Thus, the greater pressure transmitted through the central bore 17 of the packer body member or mandrel 15 to within the inner bore 102 of the anchor 100 will act through the inner port 121 to drive the upper piston member 113 upwardly until its upper face engages a downwardly directed housing shoulder 131. At the same time, however, this greater pressure is acting through the inner port 129 on the lower face of the lower piston member 126 to drive this piston upwardly to develop a hydraulic pressure within the fluid-filled hydraulic system. This pressure so developed will of course be equal to the fluid pressure within the inner bore 102 of the anchor. This developed hydraulic pressure is, however, greater than the pressure of the fluids above the packing means outside of the piston members 103 so that the casingengaging members will be driven outwardly and pressed against the casing with a force proportionately related to the pressure diflerential across the set packing means.

Where the conditions within the well are reversed and the pressure of the fluids above the set packing means is greater than that therebelow, the higher pressure is now outside of the anchor 100 and will act through outer port 119 to drive the upper piston member 113 downwardly. As this piston member 113 is driven downwardly, it will also develop a pressure within the fluid-filled hydraulic system. This developed pressure, however, will be proportionately greater than the pressure of the fluids in the well above the packing means as determined by the ratio of the eifective cross-sectional area of the enlarged portion 114 divided by that of the reduced portion 115 of the upper piston member 113. It is necessary, of course, that this developed hydraulic pressure be greater than that of the fluids above the packing means since this latter pressure is simultaneously imposed against the outer faces 107 of the casing-engaging members 103. Thus, by developing this greater hydraulic pressure, the casing-engaging piston members 103 will again be pressed outwardly into engagement against the casing with a force proportionately related to the pressure differential across the set packing means.

It will be understood, of course, that whenever the anchor 19% and the full-bore packer are being shifted in either direction through the fluid-filled well bore, the leaf springs 106 can be made sufficiently strong to prevent the casing-engaging piston member 103 from inadvertently extending. Furthermore, it will be appreciated that as the anchor 100 is being pulled upwardly through a fluidfilled well bore, any tendency of well fluids acting through the outer port 119 to shift the upper piston 113 and develop a slight hydraulic pressure will be resisted by the compression spring 123.

It will be realized that either the anchor 14 or anchor 100 will be effective as an anchor for well tools in other situations so long as a fluid pressure differential exists. For example, by placing a choke in the central bore of either of the

anchors

14, 106 the passage of fluids through the bore would create a pressure differential which could be utilized for acutating the anchor.

Thus, it will be appreciated that the present invention provides new and improved anchors for securing well tools within a well bore. These anchors will be effective to prevent a well tool from being shifted Within a well bore by extreme pressure differentials acting against it from either direction. applied by the new and improved anchors will be proportionately related to the pressure differential acting on the tool.

While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall Within the true spirit and scope of this invention.

What is claimed is:

1. A well packer sized and adapted for reception in a well bore including: means for packing-off a well bore; anchoring means on said well packer including extendible fluid-actuated wall-engaging means for engaging the wall of a well bore; and hydraulic means selectively responsive to a fluid pressure differential in a well bore either above or below said packing-off means for developing an actuating pressure to extend and press said wall-engaging means into anchoring engagement with a force proportionate to this pressure differential to anchor said well packer.

2. A well packer sized and adapted for reception in a well bore including: means for packing-off a well bore; means responsive to hydraulic pressure for anchoring said well packer relative to the wall of a well bore; and means for applying hydraulic pressure to said anchoring means in response to a pressure differential acting from either above or below said packing-off means for anchoring said well packer to the well bore with a force dependent upon said differential pressure across said packing-off means.

3. In a well packer sized and adapted for reception in a well bore: a tubular housing; packing means operatively mounted on said housing and adapted for expansion into sealing engagement with a well bore; means for selectively expanding said packing means including a body member operatively arranged within said housing; anchoring means adapted to secure said packer against longitudinal movement relative to the well bore whenever said packing means is sealingly engaged including outwardly-extendible wall-engaging means on said body member responsive to hydraulic pressure to press said wall-engaging means into anchoring engagement with the Well bore; and hydraulic means responsive to a pressure differential acting from either above or below said packing means for applying a hydraulic pressure to press said wall-engaging means into Furthermore, the anchoring forces 0 anchoring engagement with a force proportionate to this pressure differential.

4. In a well packer sized and adapted for reception in a well bore; a tubular housing; packing means operatively mounted on said housing and adapted for expansion into sealing engagement with a Well bore; means for selectively expanding said packing means including a body member having a radial bore and being operatively arranged Within said housing; anchoring means adapted to secure said packer against longitudinal movement relative to the well bore whenever said packing means is sealingly engaged including a piston member slidably disposed in said radial bore and fluidly sealed therein to provide a fluidtight space therein, said piston member being adapted to move outwardly, upon application of hydraulic pressure in said fluid-tight space, into anchoring engagement with the well bore; and hydraulic means responsive to a pressure differential acting from either above or below said packing means for applying a hydraulic pressure in said fluid-tight space to press said piston member into anchoring engagement with a force proportionate to this pressure differential.

5. In a well packer sized and adapted for reception in a well bore: a tubular housing; packing means operatively mounted on said housing and adapted for expansion into sealing engagement with a well bore; means for selectively expanding said packing means including a body member operatively arranged within said housing; anchoring means adapted to secure said packer against longitudinal movement relative to the well bore Whenever said packing means is sealingly engaged including an inflatable sleeve sealingly mounted around said body member to provide a fluid-tight space therebetween and wall-engaging means mounted around said sleeve, said sleeve being adapted to inflate, upon application of hydraulic pressure in said fluidtight space, to press said wall-engaging means into anchoring engagement with the well bore; and hydraulic means responsive to a pressure differential acting from either above or below said packing means for applying a hydraulic pressure in said fluid-tight space to press said Wall-engaging means into anchoring engagement with a force proportionate to this pressure differential.

6. The packer of claim 5 wherein said wall-engaging means comprise: a plurality of elongated and arcuate rigid backing members circumferentially spaced around said sleeve to substantially enclose it except at gaps between adjacent longitudinal edges of said backing members; first elongated wall-engaging members mounted on each of said backing members and extending longitudinally thereon substantially the full length of said backing members; second elongated wall-engaging members disposed between adjacent ones of said first wall-engaging members and extending substantially the full length of said backing members to cover said gaps; and abutment means on said body member at each end of said wallengaging members for limiting them to substantially lateral movement; and piston means between said sleeve and each of said abutment means and movable longitudinally toward the ends of said wall-engaging members in response to said hydraulic pressure for covering the portions of said sleeve between said ends and said abutment means.

7. In a well packer sized and adapted for reception in a well bore: a tubular housing; packing means operatively mounted on said housing and adapted for expansion into sealing engagement with a well bore; means for selectively expanding said packing means including a body member having a chamber therein and being operatively arranged within said housing; anchoring means adapted to secure said packer against longitudinal movement relative to the well bore whenever said packing means is sealingly engaged including outwardly-extendible wall-engagin g means mounted on said body member and fluidly sealed relative thereto to provide a fluid-tight space therebetween, said wall-engaging means being adapted to extend, upon application of hydraulic pressure in said fluid-tight space, into anchoring engagement with the well bore; and hydraulic means responsive to a pressure differential across said packing means for applying a hydraulic pressure in said fluid-tight space to press said wall-engaging means into anchoring engagement with a force proportionately related to this pressure differential including a pistonmember slidably disposed within said chamber and adapted to shift therein in response to this pressure differential; means fluidly sealing said piston member within said chamber for fluidly isolating a portion of said chamber; and passage means providing fluid communication between said isolated chamber portion and said fluid-tight space, all being filled with a hydraulic fluid.

8. In a well packer sized and adapted for reception in a well bore: a tubular housing; packing means operatively mounted on said housing and adapted for expansion into sealing engagement with a well bore; means for selectively expanding said packing means including a body member having a cylindrical chamber therein and being operatively arranged within said housing; anchoring means adapted to secure said packer against longitudinal movement relative to the Well bore whenever said packing means is sealingly engaged including outwardly-extendible wall-engaging means mounted on said body member and fluidly sealed relative thereto to provide a fluid-tight space therebetween, said wall-engaging means being adapted to extend, upon application of hydraulic pressure in said fluid-tight space, into anchoring engagement with the well bore; and hydraulic means responsive to a pressure differential acting from either above or below said packing means for applying a hydraulic pressure in said fluid-tight space to press said wall-engaging means into anchoring engagement with a force proportionately related to this pressure differential including first and second piston members slidably disposed within said chamber and adapted to shift therein in response to this pressure differential; first and second means respectively fluidly sealing said piston members within said chamber for fluidly isolating separate portions of said chamber; first passage means providing fluid communication from the well bore at a point longitudinally displaced in one direction from said packing means to said chamber adjacent one end of said first piston member; second passage means providing fluid communication from the well bore at a point longitudinally displaced in the other direction from said packing means to said chamber adjacent one end of said second piston member; and third passage means providing fluid communication from said chamber adjacent the other ends of said piston members to said fluid-tight space, all being filled with a hydraulic fluid.

9. In a well packer sized and adapted for reception in a well bore: a tubular housing; packing means operatively mounted on said housing and adapted for expansion into sealing engagement with a well bore; means for selectively expanding said packing means including a body member having a cylindrical chamber therein and being operatively arranged within said housing; anchoring means adapted to secure said packer against longitudinal movement relative to the well bore Whenever said packing means is sealingly engaged including outwardly-extendible wall-engaging means mounted on said body member and fluidly sealed relative thereto to provide a fluid-tight space therebetween, said wall-engaging means being adapted to extend, upon application of hydraulic pressure in said fluid-tight space, into anchoring engagement with the well bore; and hydraulic means responsive to a pressure differential acting from either above or below said packing means for applying a hydraulic pressure in said fluid-tight space to press said wall-engaging means into anchoring engagement with a force proportionately related to this pressure differential including first and second piston members slidably disposed within said chamber and adapted to shift therein in response to this pressure differential, said first piston member being adapted to engage and shift said second piston member whenever said first piston member shifts toward said second piston member; first and second means respectively fluidly sealing said piston members within said chamber for fluidly isolating separate portions of said chamber; first and second passage means respectively providing fluid communication from the well bore at points separated from one another by said packing means to said chamber on opposite sides of said first piston member; and third passage means providing fluid communication from said chamber at a point adjacent the other end of said second piston member to said fluid-tight space, all being filled with a hydraulic fluid.

10. In a well packer sized and adapted for reception in a well bore: a tubular housing; packing means operatively mounted on said housing and adapted for expansion into sealing engagement with a well bore; means for selectively expanding said packing means including a body member having a cylindrical chamber with a first portion of a greater cross-sectional area than the remaining portion of said chamber, said body member being operatively arranged within said housing; anchoring means adapted to secure said packer against longitudinal movement relative to the well bore whenever said packing means is sealingly engaged including outwardly-extendible Wall-engaging means mounted on said body member and fluidly sealed relative thereto to provide a fluid-tight space therebetween, said wall-engaging means being adapted to extend, upon application of hydraulic pressure ir said fluidtight space, into anchoring engagement with the well bore; and hydraulic means responsive to a pressure differential acting from either above or below said packing means for applying a hydraulic pressure in said fluid-tight space to press said wall-engaging means into anchoring engage ment with a force proportionately related to this pressure differential including a first piston member slidably disposed in said first chamber portion; a second piston member slidably disposed in said remaining chamber portion; said first piston member being adapted to engage and shift said second piston whenever said first piston member shifts toward said second piston member; first and second means respectively fluidly sealing said piston members relative to said chamber; first and second passage means respectively providing fluid communication from the well bore at points separated from one another by said packing means to said chamber on opposite sides of said first piston member; and third passage means providing fluid communication from said remaining chamber portion at a point separated from said first chamber portion by said second piston member to said fluid-tight space, said remaining chamber portion, fluid-tight space and third passage means being filled with a hydraulic fluid.

11. In a well packer sized and adapted for reception in a Well bore: a tubular housing; packing means operatively mounted around said housing and adapted for expansion into sealing engagement with a well bore; slip members movably mounted on said housing adjacent one end of said packing means and operatively arranged and adapted for outward extension into anchoring engagement with a well bore to secure said packer against 1ongitudinal movement in one direction relative to the Well bore; means for selectively extending said slip members and expanding said packing means including a body member engaged with the other end of said packing means, said body member having a cylindrical chamber therein with a first portion of a greater cross-sectional area than the remaining portion of said chamber, said body member being operatively arranged within said packing means and extending into said housing; an inflatable elastomeric sleeve sealingly mounted around said body member to provide a fluid-tight space therebetween at a point longitudinally displaced in one direction from said other end of said packing means; wall-engaging means operatively mounted around said elastomeric sleeve, said elastomeric sleeve being adapted to inflate, upon application of hydraulic pressure in said fluid-tight space, to press said wall-engaging means into anchoring engagement with the well bore and secure said packer against longitudinal movement in the opposite direction; and hydraulic means responsive to a pressure differential acting from either above or below said packing means for applying hydraulic pressure in said fluid-tight space to press said wall-engaging means into anchoring engagement with a force proportionately related to this pressure differential including; first and second slidable piston members respectively disposed in said first and remaining chamber portions; said second piston member being adapted to be engaged by said first piston member and shifted thereby whenever said first piston member shifts toward said second piston member; first and second means respectively fluidly sealing said piston members within said chamber; first passage means providing fluid communication between the well bore from a point longitudinally displaced in said one direction from said packing means to said first chamber portion at a point separated from said remaining chamber portion by said first piston member; second passage means providing fluid communication between the well bore from a point longitudinally displaced in the opposite direction from said packing means to said chamber at a point intermediate said piston members; and third passage means providing fluid communication from said remaining chamber portion at a point separated from said first chamber portion by said second piston member into said fluid-tight space, said remaining chamber portion, fluid-tight space and third passage means being filled with a hydraulic fluid.

12. As a sub-combination, an anchor comprising: a housing; a resilient sleeve disposed around said housing and sealingly secured at each end thereof to said housing to provide an enclosed space between said sleeve and housing; a plurality of elongated and arcuate rigid backing members circumferentially spaced around said sleeve and having adjacent longitudinal edges; first wall-engaging vide an enclosed space between said sleeve and housing;

means on each end of said sleeve for fluidly sealing said sleeve ends to said housing and preventing outward distortion of said sleeve ends; a plurality of elongated and arcuate rigid backing members between said end-sealing means and circumferentially spaced around said sleeve to Jbstantially enclose said sleeve except at gaps between adjacent longitudinal edges of said backing members; first.

elongated wall-engaging members mounted on each of said backing members; second elongated wall-engaging members disposed between adjacent ones of said first wallengaging members and covering said gaps; and abutment means on said housing at each end of said members for limiting said members to substantially lateral movements.

References Cited by the Examiner UNITED STATES PATENTS 2,370,832 3/1945 Baker 166-120 2,603,163 7/1952 Nixon 166212 2,881,841 4/1959 Page l66212 2,925,128 2/1960 Page 166121 2,970,651 2/1961 Roberts 166--212 3,008,523 11/1961 Clark et al l66l34 X 3,211,227 10/1965 Mott 166l20 3,233,675 2/1966 Tamplen et al. 166-420 CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner.

Claims

2. A WELL PACKER SIZED AND ADAPTED FOR RECEPTION IN A WELL BORE INCLUDING: MEANS FOR PACKING-OFF A WELL BORE; MEANS RESPONSIVE TO HYDRAULIC PRESSURE FOR ANCHORING SAID WELL PACKER RELATIVE TO THE WALL OF A WELL BORE; AND MEANS FOR APPLYING HYDRAULIC PRESSURE TO SAID ANCHORING MEANS IN RESPONSE TO A PRESSURE DIFFERENTIAL ACTING FROM EITHER