Patent Publication Number: US-8973667-B2

Title: Packing element with full mechanical circumferential support

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to the design of packer devices in subterranean wells. 
     2. Description of the Related Art 
     Inflatable packers are used to create seals within tubular members in wells. An inflatable packer typically includes a flexible packer element that is inflated with fluid to cause the packer element to expand radially outwardly from a mandrel and into sealing contact with a surrounding tubular member. The packer element is typically formed of rubber or another elastomer and may be reinforced with flexible axially-extending ribs. 
     Inflatable packers may be prone to leakage of fluid or reduction in interior pressure over the long term which may undesirably unset the packer or lead to leakage across the packer. 
     SUMMARY OF THE INVENTION 
     The invention provides methods and devices for supporting an inflatable packer element with an interior swage that is selectively radially expandable from a reduced diameter condition to an enlarged diameter condition. In the enlarged diameter condition, the swage provides mechanical support for the packer element around substantially the complete or full interior circumference of the packer element. In some embodiments, the swage can be moved back from the enlarged diameter condition to the reduced diameter condition in order to unset the packer device. 
     In accordance with particular embodiments of the invention, the swage has opposing rows of arcuate segments. In embodiments, the segments have tapered edge portions and are preferably slidably interconnected with each other using a tongue-in-groove or similar arrangement. When the opposing rows of arcuate segments are axially compressed, they move radially outwardly, expanding the packer element into sealing contact with a surrounding tubular member and providing full mechanical circumferential support to the packer element. 
     The packer membrane can have a number of configurations. In one described embodiment, the packer element includes an elastomeric membrane. According to some embodiments, the packer membrane includes reinforcing metal ribs that are located radially within the elastomeric membrane. In a further exemplary embodiment, a second elastomeric membrane is located radially within the reinforcing ribs. 
     In still other embodiments, the packer element provides additional features that allow for improved sealing. According to particular embodiments, annular reinforcing ridges of the packer element are corrugated using either “U” or “V” shaped corrugations. Bonded elastomer is preferably used to cover the corrugated outer and inner surfaces. 
     A packer device in accordance with the present invention may be incorporated into a running string along with complimentary components, such as slip assemblies which will help secure the packer device in place within a surrounding tubular member. Also according to particular embodiments, a setting tool is incorporated into the running string along with the packer device which is capable of setting the packer device via shifting of a setting sleeve to axially compress and set the swage as well as neighboring devices, such as slip assemblies. 
     According to exemplary methods of operation, the packer device is incorporated into a running string and disposed into a surrounding tubular member or string. The packer device is then disposed to a desired location within the surrounding tubular member or string. Thereafter, the setting tool is actuated to cause the packer device to be set by moving the swage to its enlarged diameter condition, which urges the packer element into sealing contact with the surrounding tubular member. In some embodiments, the packer device can be later unset by moving the swage back to its reduced diameter condition, which permits the packer device to be removed from the surrounding tubular member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages and further aspects of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein: 
         FIG. 1  is a side, partial cross-sectional view of an exemplary wellbore having a packer device constructed in accordance with the present invention. 
         FIG. 2  is a side, one quarter-sectional view of portions of an exemplary packer device constructed in accordance with the present invention, in an unset position. 
         FIG. 3  is a side, one quarter-sectional view of the portions of the packer device shown in  FIG. 2 , now in a set condition. 
         FIG. 4  is an isometric view of an exemplary swage and surrounding components with the packer element removed. 
         FIG. 5  is an isometric view of the swage and surrounding components shown in  FIG. 4 , now in an expanded diameter condition. 
         FIG. 6  is a cross-sectional view of an exemplary packer element that could be used with the packer device shown in  FIGS. 2-3 . 
         FIG. 7  is a cross-sectional view of an alternative exemplary packer element that could be used with the packer device shown in  FIGS. 2-3 . 
         FIG. 8  is a cross-sectional view of a further alternative exemplary packer element that could be used with the packer device shown in  FIGS. 2-3 . 
         FIG. 9  is a cross-sectional view of an exemplary packer element that could be used with the packer device shown in  FIGS. 2-3 , including outer corrugated ridges. 
         FIG. 9A  is a cross-sectional view of the packer element shown in  FIG. 9 , now in a radially expanded condition. 
         FIG. 10  is a cross-sectional view of a further exemplary packer element that could be used with the packer device of  FIGS. 2-3 , also including outer corrugated ridges. 
         FIG. 10A  is a cross-sectional view of the packer element shown in  FIG. 10 , now in a radially expanded condition. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates an exemplary wellbore  10  that has been formed in the earth  12 . The wellbore  10  is lined with metallic casing  14 . A running string  16  is shown disposed within the wellbore  10 . The running string  16  may be made up of a string of production tubing segments or by coiled tubing, or in other ways known in the art. 
     A packer device  18 , constructed in accordance with the present invention, is incorporated into the running string  16 . In  FIG. 1 , the packer device  18  is shown in an unset condition so that it does not form a seal against the surrounding tubular casing  14 . Dashed lines are used to depict the packer device  18  in a set position, so that a seal is formed against the casing  14 . 
       FIGS. 2 and 3  illustrate an exemplary hydraulically-set packer device  18  in one-quarter side cross-section. Several of the drawings illustrate the use of fluid seals, such as annular elastomeric O-ring seals and the like. Since the use of such seals is well known in the art, these will not be discussed in any detail. In  FIG. 2 , the packer device  18  is in an unset condition, while  FIG. 3  shows the packer device  18  set against the casing  14 . The exemplary packer device  18  includes, at its upper end, a gage ring  20  that is axially secured to the running string  16  by an upper snap ring  22 . The gage ring  20  is threadedly secured to a retainer ring  24 . The retainer ring  24  preferably includes a fluid bleed passage  26  having a one-way check valve  28  therein of a type known in the art. The upper end of packer element  30  is secured between the retainer ring  24  and upper seal ring  32 . In the embodiment shown in  FIGS. 2 and 3 , the packer element  30  is made up of an elastomeric membrane or sleeve  34  and supporting longitudinal ribs  36 . The lower end of the packer element  30  is secured between lower seal ring  38  and annular cylinder  40 . The cylinder  40  is threadedly affixed to cover ring  42 , which is axially secured to the running string  16  via snap ring  44 . The cylinder  40  surrounds the running string  16  and defines an enlarged-diameter interior chamber portion  46 . 
     It is noted that, in the depicted embodiment, the running string  16  defines a central fluid flowbore  48  along its length which permits hydraulic fluid to be pumped down from the surface to the packer device  18 . A fluid flow port  50  is provided through the running string  16  to permit fluid to be transmitted from the flowbore  48  into the interior chamber portion  46  of the cylinder  40 . 
     An axially moveable annular piston  52  is disposed within the interior portion  46  of the cylinder  40  and is initially secured to the running string  16  by a frangible shear screw  54 . In addition, the piston  52  is provided with a body lock ring assembly, generally shown at  56 , that ensures one-way ratchet-type movement of the piston  52  with respect to the running string  16 . Body lock ring assemblies are well known in the art. As depicted, the exemplary body lock ring assembly  56  includes a ratchet surface  58  that is formed on the outer radial surface of the running string  16  and a locking ring  60  that is loosely retained by the piston  52 . The locking ring  60  presents an inwardly-facing ratchet surface  62  that is generally complimentary to the surface  58  of the running string  16 . The body lock ring assembly  56  permits the piston  52  to be moved axially upwardly with respect to the running string  16 , but prevents reverse movement of the piston  52 . 
     A radially expandable swage assembly, generally shown at  64 , is located radially within the packer element  30  and radially outside of the running string  16 . An exemplary swage assembly  64  is shown in greater detail in  FIGS. 4 and 5 . It is noted that features and aspects of similar radially expandable swage devices are described in U.S. Pat. No. 7,549,469 issued to Garcia. The Garcia patent is owned by the assignee of the present application and is herein incorporated by reference in its entirety. The exemplary swage assembly  64  includes first and second annular rows of wedge-shaped arcuate segments  66 ,  68  which overlap each other and are axially movable with respect to each other. The first and second rows of segments  66 ,  68  are moveable between a first, offset configuration (shown in  FIGS. 2 and 4 ) and a second, generally aligned configuration ( FIGS. 3 and 5 ). In the first configuration, the segments  66 ,  68  present an annular formation having a reduced diameter. In the second configuration, the segments  66 ,  68  present an annular formation having an enlarged diameter.  FIG. 5  depicts the segments  66 ,  68  as being completely aligned with each other. However, those of skill in the art will understand that the segments  66 ,  68  may still be offset to some degree in the generally aligned position wherein the swage assembly  64  is set. Therefore, it is intended that, in the generally aligned configuration, the segments  66 ,  68  are more aligned than in the first, offset configuration, but need not be completely aligned. It is noted that the segments  66 ,  68  are each wedge shaped such that they present edge portions  70  that converge toward their distal ends  72 . In the depicted embodiment, a tongue-and-groove arrangement, generally indicated at  74 , is used to ensure that the segments  66 ,  68  remain slidably interconnected with one another. 
     In the embodiment depicted in  FIGS. 3 and 4 , the proximal ends  76  of the first row of segments  66  are mechanically interlocked with the retainer ring  24 . The proximal ends  78  of the second row of segments  68  are mechanically interlocked with the piston  52 . The interlocking connections between the segments  66  and  68  and the ring  24  and piston  52  are preferably such that the segments  66 ,  68  are free to move radially outwardly relative to the ring  24  and piston  52 . 
     In order to actuate the packer device  18 , fluid pressure is increased within the flowbore  48  of the running string  16 . Fluid flows into the chamber portion  46  via flow port  50 . Fluid pressure will bear upon the lower end of piston  52  and urge it axially upwardly with respect to the running string  16 , rupturing shear screw  54 . 
     As the piston  52  is moved axially upwardly with respect to the running string  16 , the swage assembly  64  is axially compressed between the retaining ring  24  and the piston  52 . As is known with regard to the operation of certain swages, the segments  66 ,  68  are moved into general axial alignment with each other, as depicted in  FIG. 5 , causing the segments  66 ,  68  to move radially outwardly with respect to the inner running string  16 . Radial outward movement of the segments  66 ,  68  will urge the surrounding packer element  30  into sealing engagement with the surrounding casing  14 , as depicted in  FIGS. 1 and 3 . 
       FIG. 6  is a cross-sectional view of an exemplary packer element  30  which might be used in the packer device  18 . The packer element  30  includes an inner elastomeric sleeve  80 . A layer of reinforcing ribs  38  radially surrounds the inner sleeve  80 . An outer elastomeric sleeve  34  radially surrounds the layer of ribs  38 . 
       FIG. 7  is a cross-sectional view of an alternative packer element  30 ′ which could also be used with the packer device  18 . The packer element  30 ′ includes a layer of reinforcing ribs  38  and a surrounding elastomeric sleeve  34 . 
       FIG. 8  is a cross-sectional view of a further alternative packer element  30 ″ which also might be used with the packer device  18 . In this embodiment, the packer element  30 ″ consists of a single elastomeric sleeve  34 . 
       FIG. 9  illustrates the outer surface of an alternative packer element  82 , in accordance with the present invention, which includes an inner elastomeric sleeve  84  and an outer elastomeric carcass  86 . The carcass  86  includes elastomer  88  that is molded onto a metallic sleeve  90 . The metallic sleeve  90  contains generally U-shaped annular corrugations that form annular ridges  92 . In one embodiment, the metallic sleeve  90  is a solid piece of cylindrical material which has corrugations machined into it. Alternatively, the corrugations could be formed in other ways known in the art. Voids  94  are located between the metallic sleeve  90  and the elastomeric sleeve  84 . During sealing by expansion of the swage  64 , the ridges  92  are expanded circumferentially and elastomer from the elastomeric sleeve  84  is urged into the voids  94 . When the swage assembly  64  expands outwardly and presses the ridges  92  of the corrugations outwardly, the voids  94  will be filled with elastomeric material from the sleeve  84 , as shown in  FIG. 9A  to provide resilient support for the ridges  92 . Also as depicted in  FIG. 9A , the elastomeric material  88  of the carcass  86  will thin. Also, the material making up the sleeve  90  may become thinner. 
       FIG. 10  depicts the outer surface of a further alternative packer element  96  which includes an inner elastomeric sleeve  98  and an outer metallic sleeve  100 . Generally V-shaped corrugations  102  are formed in the metallic sleeve  100 . An outer elastomeric sleeve  104  is bonded to the metallic sleeve  100 .  FIG. 10A  depicts the alternative packer element  96  in a set, radially expanded position. It can be seen that some or all of the end points of the corrugations  102  penetrate the outer elastomeric sleeve  104 . The interior elastomeric material of the inner sleeve  98  provides resilient support for the corrugations  102 . 
     In addition to its use in hydraulically-set packer devices, such as the packer device  18  described previously, packer devices constructed in accordance with the present invention may also be used within mechanically-set wireline-run assemblies, as are known in the art. In addition, packer devices constructed in accordance with the present invention may be incorporated into assemblies which also include one or more compression-set slip devices, of a type known in the art, to mechanically lock the packer device within a surrounding tubular member. 
     Those of skill in the art will understand that, while the exemplary packer device  30  is shown forming a seal with surrounding casing  14 , the devices and methods of the present invention may be used with a variety of other surrounding tubular members, including liners and tubing members. 
     The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to those skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope and the spirit of the invention.