Abstract:
A T-shaped slip is retained in an opening of a slip ring to drive the slip in opposed directions to and away from the surrounding borehole wall along a cone. The slip ring and cone do not come together when the slip is engaged. The opening allows release of a lock ring first with the slip engaged followed by release of the slip from the borehole wall. The slip ring and cone come together during removal from the borehole. A travel stop on the axial slip movement is provided to prevent guides on the slip from exiting a track or dovetail on the cone when the slip ring and cone are in contact during removal of the plug or packer. Extension of the guide from the cone track can happen if the slip moves through an enlarged portion of the borehole. The travel stop prevents this.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a Continuation-in-Part and claims priority to U.S. application Ser. No. 15/214,202 filed on Jul. 19, 2016. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The field of this invention is packers or bridge plugs for borehole use and more particularly where the slips are edge guided and because of the configuration of the slips and the associated slip ring the slips are retained by a travel stop that prevents slip exit from the guides which could cause a loss of the slip as the packer or plug is pulled through larger tubulars than where it was originally set. 
       BACKGROUND OF THE INVENTION 
       [0003]    There are a variety of slip designs in use and various techniques are used to retain the slips to a housing so that upon release of the packer or bridge plug the slips stay connected to the housing so that the slips come out in tandem with the housing. Most of these designs are concerned with limiting radial movement of slips pushed out radially during the set. Some examples of designs involving retaining movement of slips are: U.S. Pat. No. 8,561,687 ( FIG. 6A  item  605 ); US 2016/0251922 ( FIG. 5A  item  512  slip ring retainer); U.S. Pat. No. 5,046,557 ( FIG. 3  items  38  and  52 ); U.S. Pat. No. 6,119,774 ( FIG. 1  item  12 ); and U.S. Pat. No. 5,727,632 ( FIG. 1 d    item  80 ). 
         [0004]    As described below in an effort to reduce the length of a packer or plug there needed to be enough lost motion among the components so that the lock holding the packer or plug set position could release first before any movement to undermine an upper slip was undertaken. This was accomplished with added length to an opening that retains a transverse portion of a T-shaped slip so that enough lost motion for the mandrel could be had before grabbing the upper slip and pulling it uphole and away from its associated slip cone. The problem that can occur in such a modified design is that on the way out of the hole the packer or plug could run into larger tubulars than the size of tubular for which the packer or plug was intended to be set. When this happens the slip can slide down far enough to move out of its guides that are located on opposed sides. The present invention provides a travel stop to halt such movement before the slip guides can exit their guide channels. If that exit were to happen in a larger tubular then the slip can come out of the slip ring and can jam the packer or plug on the way out of the hole forcing a milling job. As an alternative travel stop the slip ring can have retainers that limit radial movement of the transverse portion of the T-shaped slip so that the slips will come out with the slip ring and will be incapable of falling out. This latter approach is more expensive to manufacture than the former solution but may be preferred in some cases. Those skilled in the art will better understand the underlying packer design and the slip travel stop feature applied to such a design from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims. 
         [0005]    Setting and unsetting of downhole tools is a common activity in the hydrocarbon exploration and recovery industry. Also due to the many different kinds of tools to be set and unset, there are various iteration of the setting and unsetting arrangements to support the goal. While many exist and function well for their intended purposes, it is also always a desire in the industry to improve efficiency, reduce cost and or improve function of all downhole tools. Arrangements then that reduce length, reduce unwanted motion in favor of facilitating wanted motion and combining functions are all desirable to the art. 
       SUMMARY OF THE INVENTION 
       [0006]    An embodiment of a gripping arrangement includes a mandrel having an axially extending groove therein, a first slip ring about the mandrel, a first cone about the mandrel spaced from the first slip ring, and a key engaged with the groove such that the key is axially movable and rotationally fixed relative to the mandrel. The key is disposed to maintain the spacing between the first slip ring and the first cone. The gripping arrangement also includes a release feature releasably interconnected with the key. 
         [0007]    An embodiment of a gripping arrangement includes a mandrel having an axially extending groove therein, a first slip ring about the mandrel, a first cone about the mandrel spaced from the first slip ring, and a key engaged with the groove and configured to be loaded to unset the gripping arrangement. 
         [0008]    An embodiment of a method for unsetting a gripping arrangement including a mandrel having an axially extending groove therein, a first slip ring about the mandrel, a first cone about the mandrel spaced from the first slip ring, and a key engaged with the groove such that the key is axially movable and rotationally fixed relative to the mandrel. The key is disposed to maintain the spacing between the first slip ring and the first cone. The gripping arrangement also includes a release feature releasably interconnected with the key the arrangement further including a second slip ring and, a second cone interactive with the second slip ring, the method including pulling on the second slip ring and the mandrel, increasing distance the second slip ring and the second cone, shifting the mandrel relative to the key, contacting the key on a shoulder of the groove, moving the first cone with the key away from the first slip ring. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0010]      FIG. 1  is a perspective view of an embodiment of a gripping arrangement as disclosed herein; 
           [0011]      FIG. 2  is a cross section view of the embodiment of  FIG. 1  in a run in condition; 
           [0012]      FIG. 3  is a cross section view of the embodiment of  FIG. 1  in a partially set condition; 
           [0013]      FIG. 4  is a cross section view of the embodiment of  FIG. 1  in a fully set condition; 
           [0014]      FIG. 4 a    is an enlarged view of a portion of the embodiment of  FIG. 1 ; 
           [0015]      FIG. 5  is a cross section view of the embodiment of  FIG. 1  in a partially unset condition; 
           [0016]      FIG. 6  is a cross section view of the embodiment of  FIG. 1  in a fully unset condition; and 
           [0017]      FIG. 7  is an enlarged view of a portion of an alternate embodiment, the figure being the equivalent of  FIG. 4 a    in the  FIG. 1  embodiment. 
           [0018]      FIG. 8  shows the relative positions of rings  28  and  26  in the run in position; 
           [0019]      FIG. 9  is the view of  FIG. 8  in the released position of the packer or plug during removal from the borehole. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0021]    Referring to  FIG. 1 , a perspective view of a gripping arrangement  10  is illustrated. The arrangement  10  includes a mandrel  12  that extends through other components of the arrangement that are introduced hereunder. The mandrel  12  includes a groove  14  therein that has varying lengths in different embodiments, to be discussed hereunder (see  FIG. 2 ). Upon the mandrel  12  are (arbitrarily introduced from downhole end to uphole end) a piston housing  16 ; a first slip ring  18 ; a first cone  20 ; slips  22 ; seal  24 ; second cone  26 ; second slip ring  28  and slips  30 . Also visible is key  32  and release feature  34 . The key  32  enables setting of the gripping arrangement without unwanted movement of the mandrel  12  relative to a structure  36  such as a casing string (see  FIG. 2 ) in which the gripping arrangement is to be set. This is accomplished by delaying the setting of the slips  22  due to an interfering condition the key  32  instigates between the first slip ring  18  and the first cone  20 . More specifically, the key  32  prevents the slip ring  18  being urged nearer the first cone  20  until other conditions precedent are met. This, then, prevents the interaction of the slips  22  with the cone  20  to move slips  22  radially outwardly into engage the structure  36 . The delay in engagement of slips  22  ensures that the slips  30  will engage the structure first. Engaging slips  30  first provides reliable location of the gripping arrangement  10  in the structure  36 . The key  32  is also beneficial in the unsetting operation also discussed more fully hereinafter. Finally, key  32  inhibits rotational movement of the mandrel  12  relative to other components of the gripping arrangement  10 .  FIG. 1  and the foregoing information will provide one of ordinary skill in the art an overview for visual perspective while reviewing the following discussion wherein additional components are introduced and discussed. 
         [0022]      FIGS. 2-6 , cross sectional views of the embodiment of  FIG. 1  allow for the introduction of some additional components not visible in  FIG. 1  and to provide a sequence view illustrating the setting and unsetting movements of the gripping arrangement  10 . 
         [0023]    Referring to  FIG. 2 , a body lock ring  38  of piston housing  16  is shown. This feature is embodiment specific in that the illustrated embodiment employs hydraulic pressure to set the arrangement  10 . Due hereto, the slip ring  18  includes a piston  40  extending therefrom or at least in contact therewith (in an embodiment where the piston  40  is a separate member from the first slip ring  18 ). Pressure through port  42  acts on chamber  44  and hence piston  40  to urge the piston and the first slip ring  18  in the direction of second slip ring  28 . The body lock ring  38  prevents relative movement of the piston housing  16  and the piston  40  in a direction opposite the direction the applied hydraulic pressure urged the piston. It will also be noted that piston housing  16  is attached to the mandrel  12  through a releasable attachment  46 , such as shear screws, whose function it is to allow for movement of mandrel  12  to unset the gripping arrangement at a later time. 
         [0024]    Moving to  FIG. 3 , it can be seen that the piston  40  has moved a distance toward the second slip ring  28 , due to fluid pressure enlarging the chamber  44 . During this movement, the force generated by fluid pressure is transferred through the piston  40 , the first slip ring  18 , the release feature  34 , the key  32 , the cone  20 , the seal  24  and the second cone  26  to cause the slips  30  to interact with the second cone  26  and move radially outwardly into engagement with the structure  36 . 
         [0025]    Once the slips  30  bite into the structure  36 , the second cone  26  becomes essentially immobile and the force generated from the piston  40  is taken up by the seal  24 . In the case of a compression element, seal  24  is compressed and radially expanded into sealing contact with the structure  36 . As the seal  24  fills any void spaces, it becomes immobile since in the compression seal embodiment it is inherently incompressible and the first cone  20  becomes consequently immobile. 
         [0026]    Referring to  FIG. 4 , force from the piston  40  is pitted against the immobile first cone  20  loading the key  32  and the release feature  34 , which in the illustrated embodiment attaches the key to the first slip ring  18 .  FIG. 4 a    is a detail view of the key  32  in the groove  14  in one embodiment. It is noted that in this embodiment the groove extends underneath the cone  20  hence requiring the cone is axially longer for the embodiment than it would have to be for the alternate embodiment illustrated in  FIG. 7 . Once a release threshold is achieved, the release feature  34  releases (as illustrated shear screws shear) and the first slip ring  18  is free to move into greater proximity with the first cone  20 . Resultantly, the slips  22  interact with the first cone  20  moving radially outwardly into contact with the structure  36 . The gripping arrangement  10  will remain set in this position until further intervention is taken. 
         [0027]    Referring to  FIG. 5 , in order to unset the gripping arrangement  10 , a straight pull on the second slip ring  28  or mandrel  12  is all that is necessary. The first action to occur subsequent to application of a tensile force on the gripping arrangement  10  through the second slip ring  28  or the mandrel  12  is that releasable attachment  46  will release at a selected force. This allows the mandrel  12  to move leftward in the figures sliding on piston  40 . Next, the slips  30  are pulled down the second cone  26  and out of engagement with the structure  36 . The energy trapped in the seal  24  will then dissipate upon additional movement of the mandrel in the leftward direction of the figures hereof. As a shoulder  50  of groove  14  (see  FIG. 4 a   ) contacts end  52  of key  32 , the key  32  is moved leftward into forced contact with first cone  20  (see  FIG. 6 ) thereby unsupporting the slips  22 . At this point the gripping arrangement  10  is unset and may be moved. 
         [0028]    In an alternate embodiment, referring to  FIG. 7 , a key  132  includes an offset portion  160  that does not extend into the groove  114  in mandrel  12 . This allows the groove  114  to be shorter and resultantly the cone  20  to be shorter axially. Benefits of the arrangement are a shorter overall length of the gripping arrangement in this embodiment while maintaining the rotational lock benefit of the foregoing embodiment. 
         [0029]    Embodiment 1: A gripping arrangement includes a mandrel having an axially extending groove therein, a first slip ring about the mandrel, a first cone about the mandrel spaced from the first slip ring, a key engaged with the groove such that the key is axially movable and rotationally fixed relative to the mandrel, the key disposed to maintain the spacing between the first slip ring and the first cone, and a release feature releasably interconnected with the key. 
         [0030]    Embodiment 2: The gripping arrangement of any prior embodiment, wherein the key includes an offset. 
         [0031]    Embodiment 3: The gripping arrangement of any prior embodiment wherein the release feature is a shear element. 
         [0032]    Embodiment 4: The gripping arrangement of any prior embodiment, wherein the release feature connects the key to the first slip ring. 
         [0033]    Embodiment 5: The gripping arrangement of any prior embodiment, further including a slip interactive with the first slip ring and the first cone. 
         [0034]    Embodiment 6: The gripping arrangement of any prior embodiment, wherein the slip is prevented from setting by the key until the release feature releases. 
         [0035]    Embodiment 7: The gripping arrangement of any prior embodiment, wherein the groove includes a shoulder configured to drive the kay to unset the gripping arrangement. 
         [0036]    Embodiment 8: A gripping arrangement including a mandrel having an axially extending groove herein, a first slip ring about the mandrel, a first cone about the mandrel spaced from the first slip ring, a key engaged with the groove and configured to be loaded to unset the gripping arrangement. 
         [0037]    Embodiment 9: A method for setting a gripping arrangement including running the gripping arrangement of any prior embodiment, the arrangement further comprising a second slip ring and, a second cone interactive with the slip ring, actuating the second slip ring and cone while delaying actuation of the first slip ring and cone, releasing the release feature, actuating the first slip ring and the first cone. 
         [0038]    Embodiment 10: The method of any prior embodiment, further including deploying a seal. 
         [0039]    Embodiment 11: The method of any prior embodiment, wherein the seal is disposed between the first and second cone. 
         [0040]    Embodiment 12: The method of any prior embodiment, wherein the seal is a compression element. 
         [0041]    Embodiment 13: The method for unsetting a gripping arrangement of any prior embodiment, the arrangement further including a second slip ring and, a second cone interactive with the second slip ring, the method including pulling on the second slip ring and the mandrel, increasing distance the second slip ring and the second cone, shifting the mandrel relative to the key, contacting the key on a shoulder of the groove, moving the first cone with the key away from the first slip ring. 
         [0042]    In the packer or plug design described above or in other designs that have a T-shape slip  30  an opening  60  has a bottom surface  62  to support transverse surface  64  of slip  30  for running in as shown in  FIG. 9 . Ultimately during the setting that brings slip ring  28  and cone  26  closer together but not into contact a force is delivered to move slips  30  axially as surface  66  engages surface  68  on slip  30 . Opposed guides  70  (only one of which is seen) slide in a track or dovetail  72  until the wickers  74  engage a surrounding tubular that is not shown. The axial movement of the slip  30  leaves the guides  70  still in track or dovetail  72  at the time the wickers  74  engage the borehole wall. The set position does not bring slip ring  28  and cone  26  together but it does allow the surface  66  to push on surface  68  of slip  30  enough to move the wickers  74  to the borehole wall. 
         [0043]    The released position of the packer or bridge plug is shown in  FIG. 9 . The slip ring  28  and the cone  26  are together. However, because the height  76  of opening  60  is configured to allow lost motion so that lock ring  38  can be released before slips  30 , there is a possibility that on removal of the packer or plug the borehole wall is enlarged. If there is no axial restraint on the downward movement of slips  30  during the removal and with slip ring  28  against cone  30 , there is a way for slips  30  to continue axial travel to the point where the guides  70  can come out of the track or dovetail  72  and literally fall out of opening  60 . Opposed tabs  78  engage cone  26  before guides  70  can move axially out of track or dovetail  72 . In that manner the engagement of the guides  70  to the track or dovetail  72  continues even if an increase in the borehole diameter on the way out of the hole allows further axial travel of the slips  30 . That axial movement is stopped by tab or tabs  78  to avoid loss of any slip  30  which could potentially jam the packer or plug in the borehole and require a milling operation. An alternative way to avoid loss of slips  30  during removal is to add a radial surface to the height  76  to limit the outward radial movement of the slips  30 . This technique requires making the slip ring  28  far more costly to manufacture and the preferred technique to avoid slip  30  loss is the addition of one or two tabs or other travel stop devices to slip  30  axial movement before guides  70  can exit track or dovetail  72 . Another alternative can be to place a pin or other travel stopping surface  80  for the slip  30  on the cone  26  at a location where the guides  70  are still in track or dovetail  72 . 
         [0044]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Further, it should further be noted that the terms “first,” “second,” and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). 
         [0045]    The teachings of the present disclosure may be used in a variety of well operations. These operations may involve using one or more treatment agents to treat a formation, the fluids resident in a formation, a wellbore, and/or equipment in the wellbore, such as production tubing. The treatment agents may be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Illustrative treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, anticorrosion agents, cement, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, flow improvers etc. Illustrative well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water flooding, cementing, etc. 
         [0046]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited.