United States Patent
`
`[19]
`
`Allen
`
`pg
`
`[45]
`
`4,224,987
`
`Sep. 30, 1980
`
`[54] WELL TOOL
`[75]
`Inventor: Richard G. Allen, Houston, Tex.
`
`Primaty Examiner—-—William F. Pate, III
`Attorney’ Agent’ or Firm_Robert A’ Felsman
`
`[73] Assignee: Brown Oil Tools, Inc., Houston, Tex.
`[21] App1_ No_; 377,121
`_
`_
`_ [22] Ffled‘
`Feb‘ 13’ 1978
`[51]
`Int. Cl.2 .................. .. E2lB 33/128; E21B 33/129
`[52] U.S. Cl. ................................... .. 166/120; 166/179 '
`[53] Field 0fSeal'C1l --------------- 165/120. 113. 179. 122,
`166/123. 133. 146, 6 PD; 175/307
`
`[56]
`
`_
`
`References Cited
`U'S' PATENT DOCUMENTS
`7/1964
`Brown ................................ .. 166/118
`8/ 1969 Cochran ..... ..
`-« 156/120
`
`8/1969
`Tucker et al.
`" 166/120
`8/1977 Crowe ...........,...................... 166/120
`4,044,826
`FOREIGN PATENT DOCUMENTS
`
`3,142,338
`3,459,261
`3,460,616
`
`[57]
`ABSTRACT
`lv(vhich seals against a
`The invgntion cltlwmpriises a1]?}iliCk€r
`surroun ing we con uit.
`epac er compr1sesaman-
`drel which carries a radially extendable seal for engag-
`ing the well conduit. A hydraulic actuator is provided
`for urging the seal to its set position against the well
`conduit. Once set, the tool is responsive to fluid pres-
`sure differentials in the well conduit across the seal in
`either longitudinal direction to tighten the seal means.
`Th
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`t
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`e ac ua or a so serves as a guar
`o
`overlie and protect the seal in its unset position, while
`the piston is designed to define auxiliary piston area to
`reduce the required setting pressure. The seal is set by
`being extruded both longitudinally and radially over a
`retainer extending radially outwardly from the mandrel.
`
`417608
`
`7/1974 U.S.S.R.
`
`............ ..'................... .. 166/ I20
`
`43 Claims, 11 Drawing Figures
`
` WEATHERFORD
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`INTERNATIONAL, LLC, et al.
`
`EXHIBIT 1018
`
`WEATHERFORD
`INTERNATIONAL, LLC, et al.
`V.
`PACKERS PLUS ENERGY
`
`SERVICES, INC.
`
`\\‘|\\ rjilllla
`
`

`
`Ufio Patent
`
`Sep. 30, 1980
`
`Sheet 1 of 5
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`4,224,987
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`

`
`1
`
`WELL TOOL
`
`4,224,987
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`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to means for sealing
`within a flow conduit for controlling fluid flow therein.
`In particular, the invention comprises a packer for seal-
`ing against a surrounding well conduit. The invention is
`particularly, though not exclusively, adapted to hydrau-
`lic set packers operated by fluid pressure applied via the
`tool mandrel and its supporting tubing string.
`2. Description of the Prior Art
`One of the problems associated with many conven-
`tional packers is that of leakage due to high pressures
`within the well conduit being sealed. For example, in a
`typical hydraulic set packer, if the pressure within the
`well exceeds the effective hydraulic setting pressure,
`leakage past the packer seal may occur. There is need
`for a relatively simple and economical packer which
`will effectively seal against such leakage without the
`application of excessive internal setting pressure and, in
`particular, one in which the seal will be tightened in its
`set position upon the presence of well pressure differen-
`tials across the seal in either longitudinal direction.
`Another problem associated with the use of conven-
`tional packers is that the seal, being generally in an
`exposed and vulnerable position on the exterior of the
`tool, is subject to damage. For example, when the tool
`is being run into the well, it may be damaged by contact
`with internal obstructions or irregularities in the well
`conduit. Rapid lowering of the packer increases the
`likelihood of such damage and may also create a swab-
`hing effect which can itself damage the seal and/or
`cause premature setting of the packer. Another occa-
`sion for seal damage may occur after the tool has been
`lowered into the desired position, but before it has been
`set, due to the abrading effects of sand and other mate-
`rial in the well fluid which may be circulated about the
`seal. Thus, in the past it has frequently been necessary to
`lower the packer into the well slowly ‘to avoid such
`damage.
`_
`Another disadvantage of many conventional hydrau-
`lic set packers is that, in order to provide an adequate
`stroke for the piston of the seal actuator, the packer
`must be made relatively long and is consequently diffi-
`cult and sometimes impossible to maneuver in tortuous
`well conduits. Attempts to shorten the overall packer
`length made at the expense of the size of the seal may
`result in reduced sealing effectiveness.
`There is therefore a need for an improved packer, and
`in particular for a hydraulic set packer, which will alle-
`viate these and other problems in conventional prior art
`tools.
`
`SUMMARY OF THE INVENTION
`
`The present invention addresses the above problems
`and provides a fluid pressure operated packer which
`includes means associated with the seal and responsive
`to well pressure differentials across the seal in either
`longitudinal direction to tighten the seal in its set posi-
`tion. This is accomplished through the provision of a
`fluid pressure reaction area adjacent one end of the seal
`which exceeds the transverse cross-sectional area of the
`other end of the seal in its unset position. Thus the
`packer will not leak even if the pressure on the high
`pressure side of the seal exceeds the effective setting
`pressure. Furthermore, the seal actuator defines pri-
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`mary and auxiliary piston areas which together exceed
`the transverse seal area in the unset position. This per-
`mits the use of an actual setting pressure less than the
`effective setting pressure.
`The packer of the invention also includes a guard
`which overlies the seal in its unset position. Thus the
`packer may be lowered into the well conduit relatively
`rapidly, abrasive fluids may be circulated about the
`packer, etc. without damage to the seal. The seal and
`guard are selectively relatively longitudinally movable
`to at least partially expose the seal for movement to its
`set position. Preferably,
`the guard is formed by the
`cylinder for the piston of the seal actuator. Since the
`unset seal
`thus occupies part of the cylinder space,
`rather than resting thereabove (as in conventional hy-
`draulic set packers) the total length of the tool is short-
`ened without sacrificing sealing effectiveness.
`The packer preferably also includes an anchor assem-
`bly comprising radially extendable gripping elements
`such as slips. The anchor assembly has a respective
`hydraulic actuator whose piston moves in a direction
`opposite that of the seal actuator during setting. Ac-
`T cordingly, the seal guard may be attached to the anchor
`actuator piston for movement therewith so that the
`guard is automatically longitudinally displaced to ex-
`pose the seal during setting. Furthermore, means such
`as shear members are provided to prevent premature
`setting of the seal and/or anchor assembly. Whereas in
`conventional packers, having a common actuator for
`the seal and anchor assemblies, it was necessary to de-
`sign such shear members to sever in a predetermined
`specific order, the shear members of the instant tool
`may be designed to shear at random or simultaneously
`due to the aforementioned actuator design.
`The present packer also preferably includes a retainer
`adjacent the end of the seal distal its actuator piston and
`extending radially outwardly from the mandrel. The
`retainer restricts movement of only the inner portion of
`the adjacent end of the seal, the outer portion being
`longitudinally movable. Thus, as the actuator piston
`moves toward the retainer, the seal is extruded both
`longitudinally and radially outwardly over the retainer.
`This provides several advantages. In the first place, the
`retainer displaces the inner extremity of the adjacent
`portion of the seal radially outwardly. Thus the total
`volume of elastomeric seal material needed to bridge
`the annulus to be sealed is reduced. Furthermore, the
`stretching of the elastomer up and over the retainer
`eliminates the possibility of buckling and consequent
`leakage along the inner extremity of the seal. Finally,
`the "retainer contributes to the seal tightening effect
`mentioned above by reducing the seal area distal the
`seal actuator.
`
`it is a principal object of the present
`Accordingly,
`invention to provide an improved fluid pressure set
`packer.
`Another object of the invention is to provide a packer
`having means for tightening the seal in its set position
`upon the presence of fluid pressure differentials therea-
`cross in either longitudinal direction in the sealed con-
`duit.
`Still another object of the invention is to provide a
`fluid pressure set packer having guard means for over-
`lying and protecting the seal in its unset position.
`A further object of the invention is to provide a hy-
`draulic set packer in which the seal in its unset position
`occupies a portion of the actuator cylinder for the seal.
`
`

`
`3
`Yet another object of the invention is to provide a
`well tool having a seal longitudinally and radially out-
`wardly extrudable over a retainer extending radially
`outwardly from the tool mandrel.
`Still other objects, features, and advantages of the
`present invention will be made apparent by the follow-
`ing description of the preferred embodiments, the draw-
`ings, and the claims.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a longitudinal quarter-sectional view of a
`packer according to the present invention just prior to
`setting.
`FIG. 2 is a view similar to that of FIG. 1 showing the
`packer in set condition.
`FIG. 3 is a view similar to those of FIGS. 1 and 2
`showing the packer released for removal from the well
`conduit.
`FIG. 4 is a transverse cross-sectional view taken
`
`’
`along line 4-—4 of FIG. 1.
`FIG. 5 is a transverse cross-sectional view taken
`along line 5-5 of FIG. 1.
`FIG. 6 is a transverse cross-sectional view taken
`along line 6—6 of FIG. 1.
`.
`FIG. 7 is a transverse cross-sectional view taken
`along line 7——7 of FIG. 2.
`FIG. 8 is a transverse cross-sectional view taken
`along line 8_—8 of FIG. 2.
`FIG. 9 is a longitudinal quarter-sectional view of a
`second embodiment of a packer in accord with the
`present invention just prior to setting.
`FIG. 10 is a view similar to that of FIG. 9 showing
`the packer in set condition.
`FIG. 11 is a view similar to those of FIGS. 9 and 10
`showing the packer in released condition.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`Referring now to FIGS. 1 and 4-6, there is shown a
`packer according to a first embodiment of the invention
`designed for use in anchoring and sealing against the
`interior of a well casing 10. While the invention will be
`described in relation to hydraulic set packers, it is appli-
`cable to any fluid pressure operated sealing tool, and
`certain features of the invention are also applicable to
`mechanically set tools. The packer includes a tubular
`mandrel assembly comprised of a main body portion 12
`and a collar 14 used to connect the main body 12 to the
`lower end of an operating string 16. The lower end of
`the main body 12 forms a threaded pin by which other
`sections of pipe or tubing, other tools, or the like may be
`connected below the packer.
`A seal assembly 18 is slidably carried about the main
`body 12. Seal assembly 18 comprises a plurality of elas-
`tomeric seal rings positioned end-to—end and encircling
`the body 12. The seal assembly has opposite axial ends
`20 and 22. Upper end 20 of the seal assembly 18 has a
`radially inner portion which abuts a retainer sleeve 24
`slidably disposed on the body 12. Upward movement of
`sleeve 24 on the body 12 is limited by the lower end of
`the collar 14. Downward movement of sleeve 24 on the
`body 12 is limited by an upwardly facing external annu-
`lar shoulder 26 on the body 12 and an opposing down-
`wardly facing internal annular shoulder 28 on the sleeve
`24. The radially outer portion of the upper end 20 of
`seal assembly 18 abuts the lower end of a restraining
`collar 30 releaseably secured to the sleeve 24 by a plu-
`rality of shear pins 31.
`
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`An anchor assembly is carried by the body 12 below
`the seal 18. The anchor assembly comprises a generally
`cylindrical slip cage 32 coaxially surrounding the body
`12. A plurality of gripping elements in the form of slips
`34 is carried by the cage 32. The slips 34 may be radially
`extended and retracted through radial openings 36 in
`the cage 32. A compression spring 38 is interp'osed
`between each of the slips 34 and the interior of the cage
`32 to bias the slips 34 radially inwardly. However, the
`slips 34 may be urged outwardly against the bias of
`springs 38, in a manner to be described more fully be-
`low, and are equipped with teeth on their radially outer
`surfaces for gripping the casing 10 to hold the packer in
`a fixed position relative thereto. A lower expander cone
`40 is threadedly secured to the body 12 and has an upper
`portion extending into the lower end of the slip cage 32.
`Cage 32 is releaseably secured to the expander 40 by a
`plurality of shear pins 42. The cage 32 extends up-
`wardly from the locus of the slips 34 to form a guard
`sleeve 32a which, in the running-in position shown in
`FIG. 1, completely covers the unset seal assembly 18
`and abuts the outer portion of the lower end of restrain-
`ing collar 30.
`A pair of actuator assemblies are carried generally
`between the seal assembly 18 and the anchor slips 34.
`The first or seal actuator assembly comprises an annular
`abutment member 44 abutting the lower end 22 of the
`seal assembly 18. The lower portion of the abutment
`member 44 is counterbored and internally threaded to
`receive the upper end of a lock sleeve 46 which extends
`downwardly along the body 12 and into the lower ex-
`pander cone 40 as shown. The member 44 is sealed with
`respect to the sleeve 32a and the body 12 by O-ring seals
`disposed in its radially outer and inner surfaces respec-
`tively. The upper portion of sleeve 32a serves as a cylin-
`der surrounding members 44 and 46 which themselves
`form the piston means of the seal actuator.
`The second or anchor actuator assembly comprises
`an upper expander cone 48 and a holder ring 50 dis-
`posed coaxially therein. Upward movement of the ring ~
`50 in the expander cone 48 is limited by a snap ring 52
`disposed in an internal annular groove in the expander
`48. Downward movement of ring 50 is limited by a lock
`ring 54, to be described more fully hereafter, located
`below ring 50 and trapped between the sleeve 46 and
`the expander cone 48. Expander cone 48 is sealed with
`respect to sleeve 32a by an O-ring carried in an external
`groove in the expander 48. Ring 50 is sealed against the
`exterior of sleeve 46 and against the interior of expander
`48 by respective O-rings 51 and 53 carried on the inte-
`rior and exterior, respectively, of holder ring 50. Thus
`expander 48 and holder ring 50 are enabled to act to-
`gether as a piston for the anchor actuator assembly.
`FIG. 1’ shows the packet in an initial condition as it
`would appear during running-in and also just prior to
`setting with the seal and anchor assemblies in their unset
`positions. All parts of the seal assembly, anchor assem-
`bly, and the two actuator assemblies are held in substan-
`tially fixed position with respect to the mandrel 12, 14
`by the cooperative relation between these parts and,
`ultimately, by three sets of shear pins 31, 42 and 52
`along with the lower. expander 40. Expander 40 is fixed
`to body 12 by the threaded connection therebetween.
`The anchor assembly 32, 34, as well as the sleeve 32a
`and integral slip cage 32, are held fixed with respect to
`the expander 40 by the set of shear pins 42. Pins 42 fix
`the anchor assembly, and prevent premature setting
`which might otherwise occur upon relative downward
`
`

`
`5
`movement of the anchor assembly over the lower ex-
`pander 40. The inner diameter of the upper portion of
`expander 40 is enlarged to receive the lower end of lock
`sleeve 46 and to form an upwardly facing shoulder 58
`which abuts the lower end of sleeve 46 thereby support-
`ing the seal actuator piston means 44, 46. Upward
`movement of the piston means 44, 46, is prevented by
`the seal assembly 18 which is constrained against radial
`deformation by the sleeve 32a and against longitudinal
`movement by the retainer sleeve 24, which abuts collar
`14, and by the restraining collar 30 connected to sleeve
`24 by shear pins 31. Finally, shear pins 56 interconnect
`the anchor actuator piston means 48, 50 with the sleeve
`32a to fix the anchor actuator assembly and prevent
`premature setting of the anchor assembly by downward
`movement of the expander 48 with respect thereto.
`The packer, in the initial condition of FIG. 1, may be
`run into the casing 10 relatively quickly as compared
`with conventional packers since the sleeve 32a covers
`and protects the seal assembly 18 from damage due to
`contact with the wellhead apparatus, casing, or other
`subsurface apparatus. The sleeve 32a also prevents the
`seal elments from extending radially due to the pressure
`differential which is developed as the packer is moved
`through a wet casing string. Once in place, sandy fluids,
`mud, or other abrasive fluids may be circulated around
`the packer without danger of erosion or other damage
`to the elastomeric seal elements, which are protected by
`sleeve 32a.
`
`The pins 42 and collar 40, which fix the guard sleeve
`32a to the body 12, and the collar 30, pins 31 and sleeve
`24, which interconnect the body 12 with the upper end
`of sleeve 32a, serve as control means to prevent relative
`longitudinal movement between seal 18 and sleeve 32::
`during running-in and thereby releasably retain sleeve
`32a in overlying relation to seal 18.
`As mentioned above, sleeve 32a forms a cylinder in
`which piston 44, 46 of the seal actuator assembly can
`reciprocate. Because the seal assembly 18 is disposed
`within, rather than "wholly above,
`this cylinder,
`the
`overall length of the packer may be relatively small
`without any substantial sacrifice of seal length and ef-
`fectiveness. Accordingly, the packer of the invention
`provides the advantages of a longer conventional hy-
`draulic set packer but is short enough to be easily ma-
`nipulated in tortuous wells having “dog legs” and like
`deviations from a straight path.
`.
`When the desired depth has been reached, the packer
`is hydraulically set by pumping a ball plug 60 down-
`wardly through the string 16 and mandrel assembly 12,
`14 until it lands on a seat sleeve 62 secured within body
`12 by shear pin 64. The application of fluid pressure to
`the body 12 via the string 16 causes the packer to set.
`FIGS. 2, 7 and 8 show the packer in set condition, and
`an understanding of the setting process may best be had
`by a comparison of those figures with FIGS. 1 and 4—6
`in conjunction with the following discussion. A plural-
`ity of ports 66 extend radially through the body 12.
`Similar ports 68 extend through the lock sleeve 46. The
`portion of sleeve 32a disposed generally between the
`anchor slips 34 and the seal assembly 18 serves as a
`common cylinder surrounding both the piston 44, 46 of
`the seal actuator assembly and the piston 48, 50 of the
`anchor actuator assembly. Fluid supplied through the
`body 12 enters this cylinder through the ports 66 and 68
`and urges piston 44, 46 upwardly and piston 48, 50
`downwardly with respect to the body 12 and well cas-
`ing 10.
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`As best shown in FIG. 1, the transverse cross-sec-
`tional. primary piston area defined by the O-rings of
`member 44 available for reaction to the fluid pressure is
`substantially equal to the transverse cross-sectional area
`of the seal assembly 18 in its unextended position. Fluid
`pressure from ports 66 not only flows into the cylinder
`formed by sleeve 32a, but also flows downwardly along
`the sleeve 46 to the lower end thereof. The lower end of
`sleeve 46 is upset on its exterior surface and is sealed
`against the interior of expander 40 by an O-ring 70. The
`transverse cross-sectional area defined within the outer
`diameter of O-ring 70 is slightly greater than the trans-
`verse cross-sectional area defined within the inner diam-
`eter. of the O-ring 51 which seals the sleeve 46 against
`the holder ring 50. Thus the portion of the lower end of
`sleeve 46 between these two O-rings defines an auxiliary
`piston area to increase the total piston area of the piston
`44, 46 with respect to the transverse cross-sectional area
`of the seal assembly 18 in its unset position. This pro-
`vides a starting boost to the upward force on the actua-
`tor assembly to initially overcome the resistive force of
`the resilient seal assembly 18 constrained between man-
`drel 12, sleeve 32a, piston 44 and members 24 and 30.
`Even more importantly, the relationship between the
`transverse cross-sectional areas of the unset seal and the
`
`seal actuator piston permits operation of the tool by an
`actual setting pressure less than the effective setting
`pressure. For example, let us assume that, with only the
`piston area defined by the O-rings of member 44 avail-
`able for setting, a pressure of 3000 p.s.i. would be re-
`quired to set the seal 18. Assume also that, once set, the
`seal 18 would prevent leakage upon the presence of well
`pressures up to 3000 p.s.i. (ignoring for the time being
`the seal tightening effect to be describedbelow). With
`the addition of the piston area defined by the lower end
`of sleeve 46, the seal 18 may be set by application of an
`actual setting pressure less than 3000 p.s.i. However,
`(again ignoring the seal tightening effect) the seal will
`still hold in the presence of well pressures up to 3000
`p.s.i. Thus the latter will be termed the effective setting
`pressure of the tool.
`'
`When sufficient upward force is exerted on the seal
`18 via the piston 44, 46, the pins 31 will shear. The
`lower end 22 of seal assembly 18 will then begin to
`move upwardly. With the restraining collar 30 thus
`released, the outer portion of the upper end 20 of the
`seal assembly will also be permitted to move upwardly
`until the collar 30 strikes the lower end of collar 14. The
`initial upward movement of theseal assembly 18 causes
`the upper end of the seal assembly to move out from
`under sleeve 32a, the elastomer being extruded radially
`outwardly and upwardly over the retainer sleeve 24.
`Continued upward movement of the piston 44, 46 urges
`the seal assembly against
`the end of the collar 30
`thereby compressing the elastomer radially outwardly
`into sealing engagement with the interior of casing 10.
`As will be described below, the setting action of the tool
`also moves the sleeve 32a downwardly relative to the
`body 12 thereby further exposing the seal 18 for engage-
`ment with the casing 10. Setting of the seal assembly 18
`isolates the areas above and below the packer so that all
`fluid flow is forced through the body 12.
`Several advantages are afforded by the provision of
`the retainer sleeve 24. Since the sleeve 24 extends radi-
`ally outwardly from the mandrel body 12, and the
`upper end of the seal assembly is forced not only up-
`wardly but also radially outwardly over the sleeve 24,
`less volume of elastomeric material is required to fill
`
`

`
`7
`and seal off the annular space between the body 12 and
`the casing 10 than would be necessary if the seal were
`simply axially compressed. Furthermore, the stretching
`of the inner extremity of the seal material over sleeve 24
`prevents buckling of the seal along its inner diameter
`and the leakage which could result therefrom.
`The fluid pressure introduced into the cylinder
`formed by sleeve 32a to set the seal also urges the piston
`48, 50 of the anchor actuator assembly in a downward
`direction with respect to the casing 10 to set the slips 34.
`When the downward force becomes great enough, the
`pins 42 and 56 will shear. The upper expander 48 may
`then move downwardly with respect to the slips 34.
`The upper and radially inner surface of each slip 34 is
`upwardly and radially outwardly inclined. The expan-
`der 48 has a correpondingly inclined conical surface
`engageable with the upper inclined surfaces of the slips
`34. Thus the downward movement of the expander 48
`with respect to the slips 34 urges the upper halves of the
`slips radially outwardly by a wedging action. The force
`on the piston 48, 50 will also cause the piston 48, 50 to
`move further downwardly toward the lower expander
`40 carrying the slip cage 32 and slips 34 with it. The
`lower inner surfaces of the slips 34 are inclined down-
`wardly and radially outwardly, and the lower expander
`40 has a correspondingly inclined conical surface
`whereby the lower halves of the slips are urged radially
`outwardly as they move down over the expander 40.
`In actual practice, the two sets of shear pins 42 and 56
`shear virtually simultaneously and the various move-
`ments described above in connection with setting of the
`anchor assembly occur almost in unison. However, it
`should be noted that if either set of pins shears before
`the other, the anchor will still be properly set. Thus, if
`pins 56 shear first, the upper expander 48 with the ring
`50 will move downwardly with respect to the slips 34
`until stopped by being wedged between the slips and
`the sleeve 46. Meanwhile, the upward force exerted on
`mandrel body 12 via piston 44, 46, seal assembly 18,
`sleeve 24 and collar 14 will cause the connected lower
`expander 40 to shear pins 42 and move upwardly behind
`slips 34 completing the setting thereof. If, on the other
`hand, pins 42 shear first, members 48, 50, 32 and 34 can
`move downwardly until the slips 34 are wedged be-
`tween the expander 40 and the casing 10. Then further
`exertion of fluid pressure will cause pins 56 to shear so
`that expander 48 can move further downwardly to set
`the upper halves of the slips 34. The downward move-
`ment of the slip cage 32 during setting of the anchor
`assembly moves the integral sleeve 32a away from the
`upper end of the seal assembly 18 to expose additional
`seal area for contact with the casing 10.
`It can be seen that, since the_ pistons 44, 46 and 48, 50
`move independently of each other with respect to the
`casing 10 and in opposite directions, setting of the seal
`assembly 18 by its actuator will not impede the setting
`movement of the other actuator or interfere with the
`setting of the anchor assembly. Likewise, setting of the
`anchor assembly will not interfere with the proper set-
`ting function of the seal assembly or its actuator. Thus
`there is no need for the pins 31 to shear in any particular
`sequential order with respect to the aforementioned
`pins 42 or 56. The various sets of shear pins which must
`be secured to set the tool may be permitted to shear at
`random, or more practically, simultaneously. Shear pin
`64 holding seat 62 in place is designed to remain intact
`until pins 31, 42 and 56 have sheared. After the packer
`is set, the continued application of increased fluid pres-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4,224,987
`
`8
`sure through the string 16 and mandrel assembly 12, 14
`will cause the pin 64 to shear permitting the seat 62 and
`ball 60 to be pumped out of the bottom of string 16
`leaving a free passage therethrough.
`The packer is held in set condition after release of the
`fluid setting pressure by a locking mechanism including
`the lower end of lock sleeve 46, lock ring 54, and an-
`chor actuator piston 48, 50. The radially outer surface
`of lock ring 54 is inclined upwardly and radially out-
`wardly. The abutting portion of the inner surface of
`expander 48 is correspondingly inclined. Thus lock ring
`54 is trapped between this inclined surface on the expan-
`der 48 and the lower end of holder ring 50 and con-
`strained to move generally with the actuator assembly
`48, 50. Nevertheless, some longitudinal play between
`ring 54 and expander 48 is permitted by virtue of the
`spacing between the inclined interior surface of the
`expander and the snap ring 52. Radial play is provided
`for by the fact that the ring 54 is a split ring as shown in
`FIG. 4.
`
`The inner surface of lock ring 54 is equipped with
`ratchet teeth. Opposable mating teeth are formed in the
`exterior of lock sleeve 46 at 72. As the packer is set, the
`teeth 72 are brought into alignment with the mating
`teeth on the lock ring 54. The inclination of the teeth is
`such as to allow upward movement of the seal actuator
`piston 44, 46 with respect to the anchor actuator piston
`48, 50 and entrapped ring 54 and/or downward move-
`ment of piston 48, 50 and ring 54 with respect to piston
`44, 46. During such movements the ring 54 and sleeve
`46 can ratchet past each other by virtue of the play
`permitted in ring 54. However, if the piston 44, 46 be-
`gins to move downwardly, or if the piston 48, 50 begins
`to move upwardly, the teeth 72 will catch the mating
`teeth of the ring 54 wedging the latter against the inte-
`rior inclined surface of the expander 48 whereby such
`relative movements of the two actuators will be pre-
`vented.
`
`With the packer in the set position of FIG. 2, the seal
`assembly 18 will be tightened in response to a well
`pressure differential across the seal in either direction. It
`is of particular significance that the seal will be tight-
`ened where the well pressure on the high pressure side
`of the seal exceeds the effective setting pressure, since
`many conventional packers will leak under such cir-
`cumstances.
`
`.
`
`Recalling the above example, assume that the packer
`has an effective setting pressure of 3000 p.s.i., although
`the actual pressure which has been applied to set the
`packer for this value is less than 3000 p.s.i. due to the
`auxiliary piston area defined between O-rings 51 and 70.
`If a pressure in excess of 3000 p.s.i. exists in the annular
`space A above seal 18 and between the mandrel 12, 14
`and the casing 10, and if this pressure is greater than the
`pressure in annulus B between the mandrel and easing
`below seal 18, there is a pressure differential across the
`seal in the downward direction. The fluid pressure in
`annulus A will act on a reaction area defined by the
`radially inner and outer extremities of the seal 18, i.e. on
`an area extending from mandrel body 12 to casing 10.
`The anchor assembly 32, 34 resists downward move-
`ment of the lower end of the seal 18, the force being
`transmitted to the anchor assembly via sleeve 32a and
`also by sleeve 46 and ring 54. Thus the lower end of seal
`assembly 18 is prevented from moving downwardly,
`and the effect of the pressure differential is to move the
`upper end of seal assembly 18 downwardly toward the
`lower end thereof. Accordingly, seal assembly 18 is
`
`

`
`4,224,987
`
`9
`further axially compressed and thereby radially tight-
`ened in its set position. In this connection, it is noted
`that some downward movement of the mandrel body 12
`may also take place. This will effect a wedging action
`on the seal 18 via the retainer sleeve 24 which enhances
`the seal tightening effect. If such downward movement
`of the mandrel body 12 should displace the lower ex-
`pander 40 from tight engagement with slips 34,
`the
`packer will still remain anchored since only the upper
`halves of the slips 34 need be firmly engaged to anchor
`the packer in the