US3623551A

US3623551A - Anchoring apparatus for a well packer

Info

Publication number: US3623551A
Application number: US56A
Authority: US
Inventors: Ervin Randermann Jr
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1970-01-02
Filing date: 1970-01-02
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30
Also published as: DE2063837B2; DE2063837C3; FR2075900A1; FR2075900B1; DE2063837A1

Abstract

Means for anchoring a well packer in a well casing, including an expander cone movable in one longitudinal direction along a mandrel and a first clutch means to prevent movement of the mandrel relative to the expander cone in the opposite direction, slips shifted outwardly by the expander cone by movement of the slips relative thereto in said one direction, and a second clutch means to prevent movement of the slips relative to the expander cone in said opposite direction.

Description

United States Patent 4/1939 Bean 2,230,712 2/1941 Bendeler et a1 166/134 X 2,965,183 12/1960 Le Bus et al. 166/217X 3,419,079 12/1968 Current 166/206 Primary Examiner-David H. Brown Attorneys-Ernest R. Archambeau, Jr., David L. Moseley,

Edward M. Roney and William R. Sherman ABSTRACT: Means for anchoring a well packer in a well casing, including an expander cone movable in one longitudinal direction along a mandrel and a first clutch means to prevent movement of the mandrel relative to the expander cone in the opposite direction, slips shifted outwardly by the expander cone by movement of the slips relative thereto in said one direction, and a second clutch means to prevent movement of the slips relative to the e pander cone in said opposite direction.

PATENTEnunv 30 1971 3,623,551

F/Gl F/G.2

Ervin Randermcmn, Jl'.

INVENTOR ATTORNEY ANCHORING APPARATUS FOR A WELL PACKER This invention relates generally to well tools, and more particularly to well packers and plugs having normally retracted slips that are expanded against the casing to anchor and prevent movement in the casing.

A well tool such as a packer or a plug typically has normally retracted slips and packing that are expanded against the easing when the tool is set. The slips prevent longitudinal movement of the tool under the influence of fluid pressure, and the packing prevents fluid movement past the sealing point of the tool. The packing is normally disposed around a mandrel between upper and lower expander cones that cooperate with the slips to expand them outwardly. A ratchet lock ring typically provides a one-way clutch to lock the tool in set condition. The lock ring can be arranged within an annular setting head located above the upper slips, however, in order to minimize the materials used in the packer and enhance the drillability thereof, the lock ring can be arranged between the upper cone and the mandrel. The foregoing structure is shown for example in U.S. Pat. No. 3,465,820, Kisling, issued Sept. 9, 1969. Inasmuch as the packing is conventionally an elastomeric material having resilience, it is generally possible to foreshorten the packing even more than it was originally foreshortened during setting. This may be accomplished, for example, by pressurizing the fluid in the casing above the packer. The greater fluid pressure will act on the transverse area of the mandrel as well as the packing mandrel to move downwardly to some extent as the packing is further compressed. The clutch between the upper cone and the mandrel will cause the upper cone to follow the mandrel downwardly and possibly away from the upper slips, thereby loosening them. Then when the pressure from above is relieved or is made greater below the tool, the mandrel and cone will be shifted upwardly and the upper slips, having been loosened, may not anchor sufficiently to maintain the packing element in packed-off condition.

The principal object of the present invention is to provide a new and improved well packer, plug or the like having slips that will follow up any additional foreshortening of the packing after the tool is set and remain in firm gripping engagement with the casing.

This and other objects are attained in accordance with the present invention by the provision in the combination of, a well packer apparatus including a mandrel carrying expansible elastomeric packing between upper and lower expander cones, upper and lower initially retracted slips that are expanded outwardly by respective expander cones, and a first one-way clutch between the upper expander cone and the mandrel to trap compression loading in the packing once the tool is set in a well casing, of a second one-way clutch that prevents movement of the slips relative to the cone in the opposite direction. Accordingly, after the tool is set, if the cone attempts to move relative to the slips in a direction that would otherwise loosen the slips, the slips and cone are constrained to move conjointly and the slips remain in gripping position against the casing, providing a more leakproof packer than has heretofore been known in the art.

A further understanding of the present invention will be provided by the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a sectional view, with portions in side elevation, of a well packer apparatus in accordance with the principles of the present invention and with slips and packing in retracted positions, and

FIG. 2 is a fragmentary, against the casing.

Referring initially to FIG. 1, there is illustrated in a somewhat schematic fashion a well tool such as a packer or a bridge plug. Of course the present invention is equally applicable to a cement retainer or to any other type of well tool having settable packing and slips. A mandrel or body member 11 has a lower guide and abutment l2 and carries one or more elastomeric packing rings 13 disposed between an upper exenlarged view of the upper slips set pander cone l4 and a lower expander cone 15. The upper expander cone 14 has an upwardly and inwardly inclined outer surface 16, whereas the lower expander cone 15 has a reverse tapered surface 17. An upper slip l8'having external wickers or teeth 19 and a tapered internal surface 20 can be shifted outwardly by the upper cone 14 into gripping engagement with a well casing to anchor against upward movement therein. The slip 18 can be provided with an annular band 21 that is force-fitted in a groove surrounding the slip in order to maintain segments of the slip in the same horizontal plane during expansion. The particular construction of the band and groove is more fully described in U.S. Pat. No. 3,497,003, Berryman et al., issued Feb. 24, I970. A lower slip 22 having external wickers or teeth 23 and a tapered internal surface 24 can be shifted outwardly by the lower cone 15 into gripping engagement with the well casing to anchor against downward movement. A split, expansible and contractable clutch ring 25 is located within an annular recess 26 in the upper cone l4 and has internal teeth 27 that coact with external teeth 28 on the mandrel 11, and external cam teeth 29 that coact with companion teeth 30 on the cone in such a manner that the mandrel 11 can be moved upwardly within the cone, but the cone cannot be moved upwardly along the mandrel. The particular clutch ring shown in the drawings is conventional and is further described in U.S. Pat. No. 2,647,584, Baker et al., issued Aug. 4, 1953.

Shear pins

31 and 32 can be used to control the relative movement sequence of various parts of the packer during setting in a typical manner.

Other conventional elements, such as detent rings, antiextrusion rings and the like, normally found in typical well packers can be provided but are not shown in order to simplify this description. Moreover, it will be understood that the slips used to anchor the packer can be conventional integral-frangible, segmented, or integral-expandable types. The packer can be set in a well casing by using a wire line gas-operated setting tool or a mechanical or hydraulic setting tool run on tubing, all of which are well known to those skilled in the art.

With further reference to FIG. 1 and particular reference to FIG. 2, showing the upper slips set against a well casing 35, the upper expander cone 14 is circumscribed by a groove 36. The inner periphery of the upper slip 18 has a plurality of buttresstype teeth 37 facing in an upward direction. A split, inherently contractable and expandible ring 38 is received in the groove 36, and has an upper surface 39 that inclines downwardly and outwardly. The groove 36 has sufficient depth such that as the slips 18 are moved downwardly along the cone [4, the ring 38 can contract inwardly and ratchet over the teeth 37. However, should the cone l4 attempt to move downwardly relative to the slips 14, the ring engages between an upper surface 40 of one of the teeth 37 and the upper wall 41 of the groove 36 to prevent relative movement. Accordingly, should the upper cone 14 move downwardly relative to the casing 35, the upper slips 18 are forced to move downwardly with it.

In operation, the parts can be assembled as shown in the drawings and the tool set in the well casing 35 in a conventional manner. The packing rings 13 are foreshortened longitudinally and expanded against the casing to provide a packofl or seal. The lower slips 22 are shifted outwardly and grip the casing to prevent downward movement, and the upper slips 18 are shifted outwardly and grip the casing to prevent upward movement. The clutch ring 25 traps the compression loading in the packing 13. Greater fluid pressure in the casing below the packer than above it will tend to force the mandrel ll upwardly, resulting in a tighter setting of the tool in the casing.

In the event that a downward force is imposed on the mandrel I], which could be due to greater fluid pressure in the casing above the packer than below it, or to pipe weight imposed thereon, or both, the packing 13 can become further foreshortened, enabling downward movement of the mandrel. The clutch ring 25 will cause the upper cone 14 to move downwardly with it. Normally, as in the prior art, such movement would tend to loosen the upper slips 18. However, due to the coaction of the lock ring 38 with the internal teeth 37 on the upper slips 18, the slips are forced downwardly relative to the casing with the cone 14 and the mandrel 11. Accordingly, the packing 13 will remain tightly compressed against the casing when the downward force is relieved, and remain in efiective sealing engagement with the casing.

Since certain changes or modifications will occur to those skilled in the art without departing from the concepts of the present invention, it is intended that the following claims cover all such changes or modifications falling within the true spirit and scope of the present invention.

1 claim:

1. A well packer apparatus comprising: a body member; normally retracted elastomeric packing means surrounding said body member; an expander cone engaging one end of said packing means; normally retracted slip means cooperable with said expander means to be shifted outwardly thereby into gripping contact with a well conduit; first one-way clutch means for enabling movement of said body member relative to said expander means in one longitudinal direction and for preventing movement of said expander means along said body member in said one direction; and second one-way clutch means for enabling movement of said slip means relative to said expander means in the opposite longitudinal direction and for preventing longitudinal movement of said slip means relative to said expander means in said one direction.

2. An anchor assembly for use in preventing movement of a well tool in a well bore, comprising: a body member; an expander cone movable longitudinally relative to said body member in one direction; clutch means for enabling movement of said cone in said one direction and for preventing longitudinal movement of said body member relative to said cone in said one direction; slip means surrounding said body member and adapted to be shifted by said cone between inner positions alongside said body member and outer positions in gripping contact with a well conduit wall; and lock means for coupling said slip means to said cone in said outer positions,

whereby said slip means and said cone are constrained to move conjointly longitudinally with respect to the well conduit wall.

3. The anchor assembly of claim 2 wherein said lock means includes an expansible and contractable ring member contracted around said cone and having teeth means cooperable with toothed surfaces on the inner periphery of said slip means.

4. The anchor assembly of claim 2 wherein said lock means includes a split ring laterally movable within a groove extending circumferentially of said cone, said ring having at least one buttress type thread formed on its outer periphery facing the direction of shifting of said slip means, and companion threads formed on inner peripheral surfaces of said slip means facing in the reverse direction, so that said slip means can be shifted outwardly along said cone toward positions against the well conduit wall and said threads will engage to prevent inward movement thereof.

5. A well packer apparatus comprising: a body member; elastomeric packing means surrounding said body member and adapted to sealingly engage a well conduit wall; an expander means adjacent said packing means said expander means having outer inclined surfaces; normally retracted slip means having inner inclined surfaces cooperable with said outer inclined surfaces whereby said slip means is shifted outwardly by movement of said slip means along said expander means in one longitudinal direction, said slip means having a toothed outer periphery adapted to grip the well conduit wall; thread means of the buttress type on said inner inclined surfaces and formed to face in the opposite longitudinal direction; and a split inherently expansible and contractable ring contracted within a groove in said expander means and having a companion thread form on its outer periphery adapted to coact with said thread means to permit shifting of said slip means along said expander means in said one direction but to prevent movement of said slip means along said expander means in said opposite direction.

Claims

2. An anchor assembly for use in preventing movement of a well tool in a well bore, comprising: a body member; an expander cone movable longitudinally relative to said body member in one direction; clutch means for enabling movement of said cone in said one direction and for preventing longitudinal movement of said body member relative to said cone in said one direction; slip means surrounding said body member and adapted to be shifted by said cone between inner positions alongside said body member and outer positions in gripping contact with a well conduit wall; and lock means for coupling said slip means to said cone in said outer positions, whereby said slip means and said cone are constrained to move conjointly longitudinally with respect to the well conduit wall.