Patent Publication Number: US-8985228-B2

Title: Treatment plug and method of anchoring and sealing the same to a structure

Description:
BACKGROUND 
     Tubular systems, such as those used in the completion and carbon dioxide sequestration industries often employ anchors to positionally fix one tubular to another tubular, as well as seals to seal the tubulars to one another. Although existing anchoring and sealing systems serve the functions for which they are intended, the industry is always receptive to new systems and methods for anchoring and sealing tubulars. 
     BRIEF DESCRIPTION 
     Disclosed herein is a treatment plug. The treatment plug includes, an anchor runnable and settable within a structure having, at least two slips movably engaged with one another to cause the at least two slips to move radially into engagement with the structure in response to longitudinal movement between the at least two slips. The treatment plug also has at least one seal having a deformable metal member configured to radially deform into sealing engagement with the structure in response to longitudinal compression of the deformable metal member, and a seat that is sealingly receptive to a plug. 
     Further disclosed herein is a method of anchoring and sealing a treatment plug. The method includes, longitudinally moving a first half of a plurality of slips relative to a second half of the plurality of slips, altering a radial dimension defined by the plurality of slips, anchoring the plurality of slips to a structure, longitudinally compressing at least one deformable member, and sealingly engaging the structure with the at least one deformable member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  depicts a cross sectional view of a treatment plug disclosed herein positioned within a structure; 
         FIG. 2  depicts a side view of the treatment plug of  FIG. 1  shown in a non-anchored and non-sealing configuration; 
         FIG. 3  depicts a side view of the treatment plug of  FIG. 1  shown in a sealed and anchored configuration; 
         FIG. 4  depicts a partial cross sectional view of a seal disclosed herein shown in a non-sealing configuration; 
         FIG. 5  depicts a partial cross sectional view of the seal of  FIG. 4  shown in a sealing configuration; 
         FIG. 6  depicts a side view of an alternate embodiment of a treatment plug disclosed herein; 
         FIG. 7  depicts a cross sectional view of the treatment plug of  FIG. 6  with a swaging tool engaged therewith; and 
         FIG. 8  depicts a cross sectional view of the treatment plug of  FIG. 6  with a plug seated thereagainst. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     Referring to  FIG. 1 , an embodiment of a treatment plug disclosed herein is illustrated at  10 . The treatment plug  10  includes an anchor  14  and at least one seal  18 , with a single seal  18  being illustrated in this embodiment, that are anchorable and sealable, respectively to a structure  22  shown herein as a casing or liner, although any tubular shaped structure, including an open earth formation borehole, could serve as the structure. 
     The anchor  14  has a plurality of slips  26 , a first half  26 A of which are movable in a first direction according to arrow ‘A’ relative to a second half  26 B movable in a second direction according to arrow ‘B;’ the first direction being longitudinally opposite to the second direction. Each of slips  26  has opposing perimetrical edges  30  that are tapered to form a perimetrical wedge shape. Additionally each of slips  26  in the first half  26 A are positioned perimetrically between adjacent slips  26  of the second half  26 B. A tongue  34  on one edge  30  fits into a groove  38  on a complementary edge  30 . This tongue  34  and groove  38  arrangement maintains the slips  26  at a radial dimension relative to each other of the slips  26 . As such, all of the slips  26  move radially in unison in response to the first half  26 A moving longitudinally relative to the second half  26 B of the slips  26 . One should appreciate that a perimetrical (indeed substantially circumferential in the Figures) dimension defined by the slips  26  will increase when the two halves  26 A,  26 B are moved longitudinally toward one another and decrease as the two halves  26 A,  26 B are moved longitudinally away from one another. A ‘T’ shaped tab  42  on each of the slips  26  is radially slidably engaged with a slot  46  in a collar  50  to allow the slips  26  to move radially while being supported in both longitudinal directions. Although not shown in the Figures, a tubular or membrane could be sealably engaged with both of the collars  50  to prevent fluidic communication between an outside and an inside of the components of the treatment plug  10  through the gaps between tabs  42  and the slots  46  or clearances between the adjacent slips  26 . 
     Optionally, teeth  54 , also known as wickers, on an outer surface  58  of the slips  26  can bitingly engage with a surface  62  of the structure  22  to increase locational retention of the anchor  14  within the structure  22 . This biting engagement can hold the two halves  26 A,  26 B relative to one another in the longitudinally compressed position so that external means of holding them in such a position is not required. 
     Referring to  FIGS. 4 and 5 , the seal  18  has a deformable metal member  66  that is radially deformable in response to longitudinal compression thereof. The seal  18  is positioned and configured such that the radial deformation causes the deformable metal member  66  to sealingly engage with the surface  62  of the structure  22 . An optional polymeric member  70  (made of polymeric material) located radially of the deformable metal member  66  may be used to improve sealing between the deformable metal member  66  and the surface  62 . 
     The deformable metal member  66  has a thin cross section in comparison to collars  74  displaced in both longitudinal directions from the deformable metal member  66 . This difference in cross sectional thickness assures that the deformable metal member  66 , and not the collars  74 , deform when longitudinally compressed. The deformable metal member  66  may also have a profile such that a longitudinal central portion  78  is displaced radially from portions  82  immediately to either longitudinal side of the central portion  78 . This relationship creates stress in the deformable metal member  66  to control a radial direction in which the central portion  78  will move when longitudinal compressive forces are applied to the deformable metal member  66 . 
     The collars  74  each have a shoulder  86  that is contactable by the deformable metal member  66  during deformation thereof. The shoulders  86  may be contoured to allow the deformable metal member  66  to follow during deformation to control a shape of the deformation. These contours can prevent sharp bends in the deformation that might result in undesirable rupturing of the deformable metal member  66  had the contours not been present. A minimum dimension  90  between the shoulders  86  may be less than a maximum longitudinal dimension  94  of the deformable metal member  66  after deformation. By plastically deforming the deformable metal member  66  the as deformed position (illustrated in  FIG. 5 ) can be maintained without having to hold the collars  74  longitudinally relative to one another as is often required of typical seal devices. 
     The seal  18  of this embodiment is further configured such that the central portion  78  is located radially within surfaces  98  defining a maximum radial dimension of the collars  74  prior to deformation of the deformable metal member  66  but is located radially outside of the surfaces  98  after deformation. It should be noted that other embodiments are contemplated wherein the direction of deformation of the deformable metal member  66  is opposite to that shown in the Figures. In such an embodiment the relationships discussed herein would be reversed. 
     Referring again to  FIG. 1 , a seat  102  is sealingly receptive to a plug  106 , shown herein as a ball, runnable there against. The seat  102  is positioned on a side of the seal  18  that is longitudinally opposite to a side on which the anchor  14  is located. Pressuring up against the plug  106  sealed against the seat  102  allows an operator employing the treatment plug  10  to do work therewith such as, fracturing an earth formation, or actuating a pressure actuator, for example, in a hydrocarbon recovery or a carbon dioxide sequestration application. Additionally, pressure applied against the seated plug  106  could be used to generate forces needed to compress the seal  18  into sealing engagement with the structure  22  or to urge the first half  26 A of the slips  26  toward the second half  26 B of the slips  26  to set the anchor  14 . 
     Referring to  FIG. 6 , an alternate embodiment of a treatment plug disclosed herein is illustrated at  110 . The treatment plug  110  includes an anchor  114  and at least one seal  118 , with a single seal  118  being illustrated in this embodiment, that are anchorable and sealable, respectively to a structure  122  shown herein as a casing or liner, although any tubular shaped structure, including an open earth formation borehole, could serve as the structure. 
     The anchor  114  has a plurality of slips  126 , a first half  126 A of which are movable in a first direction according to arrow ‘C’ relative to a second half  126 B movable in a second direction according to arrow ‘D,’ the first direction being longitudinally opposite to the second direction. Each of slips  126  has opposing perimetrical edges  130  that are tapered to form a perimetrical wedge shape. Additionally each of slips  126  in the first half  126 A are positioned perimetrically between adjacent slips  126  of the second half  126 B. As such, all of the slips  126  move radially in unison in response to the first half  126 A moving longitudinally relative to the second half  126 B of the slips  126 . One should appreciate that a perimetrical (indeed substantially circumferential in the Figures) dimension defined by the slips  126  will increase when the two halves  126 A,  126 B are moved longitudinally toward one another and decrease as the two halves  126 A,  126 B are moved longitudinally away from one another. A ‘T’ shaped tab  142  on each of the slips  126  in the second half  126 B is radially slidably engaged with a slot  146  in a collar  150  to allow the slips  126 B to move radially while being supported in both longitudinal directions. The slips  126  of the first half  126 A differ from the slips  26 A of the anchor  14  in that the slips  126 A do not include ‘T’ shaped tabs but instead are integrally formed as part of a sleeve  132 . As such an area  140  defined where the sleeve  132  and fingers  136  of the slips  126 A meet will deform as the fingers  136  radially expand while the sleeve  132  does not. 
     Another difference between the anchor  114  and the anchor  14  is that each of the slips  126  has a plurality of wedge shaped portions  144  displaced longitudinally from one another. The illustrated embodiment includes three such wedge portions  144  although any practical number of the wedge portions  144  is contemplated. One effect of employing more than one of the wedge portions  144  is the anchor  114  is able to engage with walls  120  of a structure  122  within which the anchor  114  is deployed over a greater longitudinal span. 
     Referring to  FIG. 7  a swaging tool  148  is shown engaged with the treatment plug  110 . The swaging tool  148  has a mandrel  152  that aligns a swage  156  and a plate  160 . The swage  156  is sized and configured to increase radial dimensions of a portion  164  of the sleeve  132  when forced therethrough. In so doing, a seal element  168  positioned radially of the portion  164  is displaced into sealing engagement with the walls  120  of the structure  122 . The plate  160  includes a shear ring  172  where it engages with a groove  176  in the collar  150 . Movement of the plate  160  towards the swage  156  of the swaging tool  148  causes the first half  126 A of the slips to move longitudinally relative to the second half  126 B of the slips  126  thereby causing them to move radially outwardly into anchoring engagement with the walls  120  of the structure  122 . The shear ring  172  is designed to shear, thereby releasing the swaging tool  148  from engagement with the treatment plug  110 , at forces greater than would be applied thereto during either of the swaging operation or the anchoring operation. As such, once swaging and anchoring is complete the swaging tool  148  can be retrieved upon shearing of the shear ring  172 . 
     Referring to  FIG. 8 , a plug  106  is shown seated on a seat  102  of the treatment plug  110  in a similar fashion as to that of the treatment plug  10  in  FIG. 1 . 
     The treatment plugs  10 ,  110  disclosed herein are designed to have a large minimum through bore dimension  180  in relation to the minimum radial dimension  184  of the structure  122  (see  FIGS. 1 and 7 ). The large dimension  180  means that the treatment plugs  10 ,  110  do not require drilling or milling therethrough prior to completion and production, as is required of typical treatment plugs, as production can flow through the minimum through bore dimension  180  directly. Typically available treatment plugs employ composite materials for the bulk of the assembly (with only the slips being made of metal) because it is easier to drill through than if the bulk of the treatment plug were made of metal, for example. Since the composite materials employed are weaker than metal the cross sectional dimensions need to be larger to support the loads encountered. These larger cross sectional dimensions equates to a smaller bore dimension through which to produce. The treatment plugs  10 ,  110  disclosed herein rely upon the high hoop strength provided by the wedge shape of the slips  26 ,  126  and the high material strength of metal employed in the slips  26 ,  126  to allow the loads to be supported while leaving the relatively large bore dimension  180  therethrough. 
     Similarly, the seals  18 ,  118  also employ relatively thin walled metal material that when deformed into sealing engagement with structures  22 ,  122  can maintain the needed sealing loads while having the large bore dimension  180  therethrough. In fact, studies have shown that the treatment plugs  10 ,  110  disclosed herein can have bore dimensions  180  that are in the range of 80% to 85% of the minimum radial dimension  184  of the structure  122 . 
     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. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.