Abstract:
A bridge plug assembly having a mandrel and an annular flexible member that is selectively fashioned into a volute that extends radially outward from the mandrel for isolating a portion of a tubular. In an example, a web member is provided that runs between the flexible member and the mandrel, and exits an end of the flexible member. Pulling the web member inverts an end of the flexible member rolling the sidewall of the flexible member into a volute. In another embodiment, upper and lower series of collars circumscribe the mandrel that when pushed towards one another axially squeeze the flexible member therebetween to outwardly bulge the flexible member into contact with a tubular. Continued force applied to the collars causes the flexible member to roll into a volute.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Application No. 61/160,458, filed on Mar. 16, 2009, the full disclosure of which is hereby incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    1. Field of Invention 
         [0003]    The invention relates generally to the field of oil and gas production. More specifically, the present invention relates to a system and method for plugging tubing within a borehole. 
         [0004]    2. Description of Prior Art 
         [0005]    Downhole plugs are used to block flow through a wellbore tubular or downhole bore for isolating a portion of the tubular. Downhole plugs, also referred to as bridge plugs, can include a mandrel having a portion circumscribed by an expandable element. The elements are typically formed from an elastomeric member or coaxially stacked members. Downhole plugs can be selectively set into place by expanding the membrane or collapsing the stacked members to block the annular space between the mandrel and tubular or bore. Plug or packer setting can occur by axially compressing the mandrel or by filling the elastomeric member with a pressurized fluid. The tubulars can be casing or production tubing. Example bridge plugs can be permanently set into a downhole tubular, or removable for later retrieval. 
       SUMMARY OF INVENTION 
       [0006]    Disclosed herein is a bridge plug assembly that can be set to block flow in a tubular, or to block flow in an annulus between two tubulars. In one example, the bridge plug assembly is made up of a mandrel circumscribed by an annular flexible member. The flexible member can have first and second ends and between the first and second ends is a portion where the sidewall of the flexible member has been rolled into an annular volute that projects radially outward into the annular space between the mandrel and the tubular. The bridge plug assembly can include an elongated continuous web member used for rolling the sidewall into a volute. In this example a portion of the web member is disposed between the flexible member and the mandrel. The web member exits the flexible member at the first end of the flexible member and projects into a space outside the flexible member and between the first and second ends of the flexible member. By pulling on the web member in a direction away from the first end the flexible member is turned inside out to form the volute. Optionally included with the embodiment of the bridge plug assembly is a ring like lip formed on the first end of the flexible member. An annular neck portion may be included adjacent the lip that is defined where the thickness of the flexible member is reduced. Additional elongated continuous web members may optionally be included and wherein free ends of the web members opposite the ends along the mandrel can be joined together to form a web harness. Example embodiments exist where the web harness connects to a downhole device. The web member can, in an example embodiment, be substantially planar with first and second planar surfaces, and wherein the first surface faces the mandrel in the portion of the web member that is between the flexible member and the mandrel and wherein the first surface faces away from the mandrel in the outer portion of the web member. Additional example embodiments exist having a cable head attached to an end of the mandrel for attachment to a wireline. 
         [0007]    In another example embodiment, included are first and second annular flange members inserted respectively into first and second ends of the flexible member. The flange members can be slidable along the mandrel. In one embodiment, further included is a collar around the mandrel that is made up of planar leaf members that project from a middle section of the collar. The leaf members can pivot from an orientation that is substantially parallel with an axis of the mandrel radially outward from the mandrel. When pivoted outward, the leaf members can form a support for the volute that resists forces directed axial to the mandrel. Example embodiments exist having a plurality of collars on opposing sides of the volute An annular sleeve may be included that slides over the mandrel and selectively contacts the collars and provide a force for outwardly pivoting the leaf members to support the volute. Operation of the sleeve can also produce outward bulging of the sleeve. In an embodiment the flexible member is attached to one of the flange members along a greater axial length than the other flange member. 
         [0008]    Also disclosed herein is a method of setting a bridge plug in a wellbore tubular In an example the method includes inserting a bridge plug assembly into a downhole tubular where the bridge plug assembly includes a mandrel and a flexible member circumscribing a portion of the mandrel. In the example method the annular flexible member is converted into a volute having a rolled up portion that fills some of the annular space between the mandrel and the wellbore tubular. The volute can be created by inverting an end of the flexible member. In an example embodiment, the flexible member is inverted by pulling on a web member that loops from within to outside of the flexible member. Optionally, the volute can be formed by axially compressing the flexible member so the flexible member bulges outward to contacts the tubular to generate a fold in the sidewall of the flexible member. Annular flanges can be inserted into opposing first and second ends of the flexible member. In another alternative, the length of contact between one of the flanges and the flexible member can be greater than the length of contact between the other flange and the flexible member. In yet another example embodiment, the thickness of the flexible member can vary along the axis of the flexible member so that when the flexible member is compressed the volute is formed that comprises at least two rolls of the sidewall of the flexible member. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]    Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
           [0010]      FIG. 1  is a sectional side view of an example of a bridge plug assembly as described herein in a non-deployed configuration. 
           [0011]      FIG. 2  is a perspective view of an example of the bridge plug assembly of  FIG. 1  in a deployed configuration. 
           [0012]      FIG. 3  is a side sectional view of the bridge plug assembly of  FIG. 2 . 
           [0013]      FIGS. 4-5  are side sectional views of an example embodiment of an alternative bridge plug assembly in a non-deployed configuration and disposed in a tubular in accordance with the present disclosure. 
           [0014]      FIG. 6  is a side sectional view of the alternative bridge plug assembly of  FIGS. 4 and 5  deployed in a tubular. 
           [0015]      FIG. 6A  is a side schematic view of a formation step of the bridge plug assembly of  FIG. 6 . 
           [0016]      FIG. 7  is a perspective view of the alternative bridge plug assembly of  FIGS. 4 and 5  deployed in a tubular. 
           [0017]      FIG. 8  is a perspective view of the alternative bridge plug assembly of  FIG. 7  in a deployed configuration. 
           [0018]      FIG. 9  is an example of a flexible membrane deployed as a single roll. 
           [0019]      FIG. 10  depicts an example of a flexible membrane deployed as a double roll. 
       
    
    
       [0020]    While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF INVENTION 
       [0021]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. For the convenience in referring to the accompanying figures, directional terms are used for reference and illustration only. For example, the directional terms such as “upper”, “lower”, “above”, “below”, and the like are being used to illustrate a relational location. 
         [0022]    It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, the invention is therefore to be limited only by the scope of the appended claims. 
         [0023]      FIG. 1  illustrates a sectional view of an example of a bridge plug assembly  18  shown made up of an elongate annular member  22  shown circumscribing a mandrel  20 . The annular member  22  may be formed from flexible material such as an elastomer or other polymeric material. An opening  27  is on an upper end  24  of the annular member  22  in which the mandrel  20  is inserted. At the opening  27 , the annular member  22  approximates a ring like structure to define a lip  28 . The thickness of the flexible member  22  reduces adjacent to the lip  28  to form a neck portion  26  that extends along the annular member  22  a distance directed away from the open end  27 . The neck portion  26  extends between the lip  28  and a transition  29  where the thickness of the annular member  22  is shown increasing. The thickness of the annular member  22  is shown linearly increasing along the transition  29 , however embodiments exist having non-linear, including exponential, thickness changes. 
         [0024]    A web harness  30  is provided having web members  31  shown wrapped around the upper end  24  of the annular member  22 . The web members  31  extend generally lengthwise on the inner and outer surfaces of the annular member  22 . The web members  31  of  FIG. 1  are shown between the annular member  22  and the mandrel  20 , wrapped transverse around the lip  28  between the inner and outer surface of the annular member  22 , and projecting along at least a portion of the outer surface of the annular member  22  substantially parallel with the portion of the web member  31  set inside the annular member  22 . The web members  31  of  FIG. 1  are substantially elongate planar strips. Example materials used in the web materials include ductile metals, woven fibers, where the fibers can be made of natural materials such as cotton, aramid, polymers, and combinations thereof. 
         [0025]    Referring now to  FIG. 2 , the bridge plug assembly  18 A is shown in a deployed configuration where, starting at the opening  27  of the upper end  24 , the annular member  22  is rolled over itself and reshaped into an annular volute  22 A. As described in detail below, the annular volute  22 A is formed by pulling the web members  31  on the outer surface of the annular member  22  in a direction away from the opening  27 . The free ends of the web members  31  on the outer surface of the annular member  22  are joined together by a link  33 . In the embodiment of  FIG. 2 , the link  33  is shown at an end of the web harness  30  distal from where the web members  31  loop over the lip  28  ( FIG. 1 ). The ends of the web members  31  on the inner surface of the annular member  22  are joined to the mandrel  20 . When in use in a borehole (not shown), the orientation of the bridge plug assembly  18  can be downward facing with the link  33  disposed farther downhole than the mandrel  20 . Alternatively, the bridge plug assembly  18  can be upward facing so that the link  33  is disposed farther uphole than the mandrel  20 . The link  33  can be secured to a downhole device  19  to provide a holding force represented by the direction of the arrow A W . The downhole device  19  can be an anchor (not shown) that couples to a tubular, a perforating gun, a packer device, a plug device, acoustic and/or nuclear interrogation devices, as well as combinations thereof. 
         [0026]    Illustrated in  FIG. 2  is an example of how the bridge plug assembly  18  is changed into a deployed configuration that can block flow within a tubular. In this example a force is applied in the direction of arrow Aw while another force, illustrated by arrow A T , is applied to the mandrel  20 . The forces represented by arrows A W , A T  pull the web members  31  on the outer surface of the annular member  22  in a direction parallel to A W . Since one of the ends of the web members  31  are joined to the mandrel  20 , the portions of the web members  31  between the annular member  22  and mandrel  20  are “peeled” away from the mandrel  20 . The peeling action puts the web members  31  in a curling motion that rolls the lip  28  along the axis A X  of the mandrel  20 . The decreased thickness of the neck portion  26  promotes rolling of the ring  28 . In an alternative, a wireline  25  may be attached to the mandrel  20  via a cablehead  21  for deploying the bridge plug assembly  18  within the borehole. 
         [0027]    As shown in the cross sectional embodiment of  FIG. 3 , the volute  22 A is made up of layers  23  of the annular member  22 . Rolling the lip  28  as described above encapsulates the lip  28  within the annular member  22  thereby forming an annular laminate. Thus continued urging of the web member  31  in direction of arrow A W  perpetuates rotation of the lip  28  further adding layers  23  to the volute  22 A and increasing the outer circumference of the volute  22 A. Optionally, an upward pull on the mandrel  20 , represented by arrow A T , such as from a wire line or slick line (not shown), can form the volute  22 A. In an example of use, the bridge plug assembly  18  is deployed within a tubular  32 , where the bridge plug assembly  18  can be upward or downward facing. The tubular  32  can be wellbore tubing, casing, or a production pipeline. An axial force, such as represented by A T , A W , or both, is applied to the bridge plug assembly  18  thereby peeling the web members  31  from the mandrel  20 . As described above, the peeling action creates a volute  22 A that increases in diameter with continued applied force. The applied force can be removed when the volute  22 A has a desired diameter. In the example embodiment illustrated in  FIG. 3 , the volute  22 A has an outer diameter that is about at least as great as the diameter of the annulus within the tubular  32  thereby providing a blocking bridge plug in the tubular  32 . Alternatively, the outer diameter of the volute  22 A may be less than the inner diameter of the annulus in the tubular  32 , thereby regulating flow through the tubular  32 . In this example, the amount of flow regulation can depend on the outer diameter of the volute  22 A. In yet another alternative, the force or forces can be continue to be applied to the bridge plug assembly  18 ,  18 A after the outer diameter of the volute  22 A grows to match or exceed the inner diameter of the annulus in the tubular  32 . Depending on the amount or duration of applied force, the volute  22 A can become wedged in the annular space between the mandrel  20  and tubular  32  so that a substantial force is required to dislodge the volute  22 A from within the tubular  32 . In an example embodiment, the deployed bridge plug assembly  18 A may be dislodged from within the tubular  32  by applying an axial force to the mandrel  20  in a direction opposite A T . 
         [0028]    Referring now to  FIGS. 4 and 5 , a side sectional view of an alternative embodiment of a bridge plug assembly  34  is illustrated. In this embodiment, the bridge plug  34  is depicted being disposed within a tubular  32 , which can be production tubing as well as casing. The bridge plug assembly  34  of this embodiment includes an upper and lower series of collars  35 ,  37  coaxially disposed around an annular mandrel  36 . It should be pointed out, however, that the position of the upper and lower series of collars  35 ,  37  is chosen for reference and may be reversed within a particular application. The series of collars  35 ,  37  each include individual annularly shaped collars  44 , that as shown in the initial configuration, are made up of leaf members  45 . 
         [0029]    The embodiment of the bridge plug assembly  34  depicted in  FIGS. 4 and 5  are shown in a non-blocking configuration to allow for insertion of the bridge plug assembly  34  within the tubular  32 . In the non-blocking configuration, the leaf members  45  ( FIG. 5 ) are generally planar and elongate shown disposed parallel with an axis A BP  of the assembly  34 . Flared ends  47  are provided on the detached or free end of each of the leaf members  45 . Each flared end  47  is oriented at an angle with respect to the remaining portion of each leaf member  45  so that when the leaf members  45  are disposed generally parallel with the mandrel  36  the flared ends  47  project away from the mandrel  36 . 
         [0030]    An annularly shaped flexible member  38  circumscribes the mandrel  36  in an axial space between the upper series of collars  35  and the lower series of collars  37 . Flange members  48  are illustrated set within opposing ends of the flexible member  38 . The flange members  48  each include a tubular portion shown inserted within the openings on each end of the flexible member  38 . A shoulder projects radially outward from an end of the tubular portion. The flange members  48  are disposed so that the shoulder is set against the ends of the flexible member  38 . The side of each shoulder opposite from the elastic member  38  contacts with the collar  44  closest to the flexible member  38 . 
         [0031]    The assembly  38  further includes a cylindrically shaped bottom end  50  shown formed on an end of the mandrel  36  and having a diameter greater than the diameters of the collars  44 . The bottom end  50  is provided on the end of the lower series of collars  37  opposite where the series of collars  37  contact one of the flange members  48 . A sliding sleeve  46  is provided on the end of the assembly  38  opposite the bottom end  50 . The sleeve  46  is annularly shaped and receives the upper end of the mandrel  36  within its annulus. 
         [0032]    A side perspective view of the upper series of collars  35  and flexible member  38  is provided in  FIG. 7 . In this embodiment, slits  49  are shown extending along a portion of the length of the collars  44  thereby defining the lateral periphery of the leaf members  45 . Additionally, an opening  43  in formed through the collar  44  for receiving the tubular  36  axially therethrough and to slide thereon. The collars  44  are shown arranged so that the slits  49  on adjacent collars  44  are at different circumferential locations around the mandrel  36 . 
         [0033]    A deployed configuration of the assembly  34  is provided in a perspective view in  FIG. 8 . As shown, the sleeve  46  has been urged over the tubular  36  and moved towards the bottom end  50  thereby coaxially sliding the collars  44  over one another to form a stacking configuration. Stacking the collars  44  outwardly pivots the leaf members  45  from the mandrel  36  forming a backstop that sets against the opposing ends of the flexible member  38 . By stacking the collars  44  as shown in  FIG. 8 , the outer periphery of the collars  44  is increased, thereby supporting the . flexible member  38  from buckling in this vicinity. Compressing the flexible member  38  bulges the midsection outward and into sealing contact with the inner surface of the tubular  32 . 
         [0034]    With reference now to  FIG. 6 , a side sectional view of the assembly  34  is shown in a deployed configuration where the flexible member  38  has been formed into a volute  38 A. Manipulating the flexible member  38  into a volute  38 A provides a more dense material between the mandrel  36  and outer tubular  32 . The higher density volute  38 A has an increased resistance to pressure differential than an inflated plug, and thus can operate in higher pressure environments. Optionally, the sleeve  46  may include a piston  40  attached on an upper end that slides within the tubular  36  as the sleeve  46  is urged against the collars  44 . 
         [0035]    In one example of use, the flexible member  38  is strategically mounted within the assembly  34  so that during deployment the flexible member  38  takes on the shape of the volute  38 A. For example, with reference to  FIG. 6 , the portion of the flexible member  38  attached to the flange member  48  proximate the piston  40  is longer than the portion of the flexible member attached to the flange member  48  distal the piston.  FIG. 6A  is a schematic representation illustrating an example of axially compressing the flexible member  38  causing it to bulge radially outward. As shown, additional axial compression of the flexible member  38  generates a fold  53  in the sidewall of the flexible member  38 . An upper attachment length L U  and lower attachment length L L  are shown respectively at ends of the flexible member  38  that schematically represent attachment lengths between the flexible member  38  and flange members  48 . Although in the embodiments of  FIG. 6  and  FIG. 6A  the upper attachment length L U  is greater than the lower attachment length L L , embodiments exist having the lower attachment length L L  being the longer of the two. Having unequal attachment lengths along opposing ends of the flexible member  38  locates the bulge between the mid-point of the flexible member  38  and the end having the shorter attachment length. Moving the flange member  48  distal from the bulge further compresses and outwardly bulges the flexible member  38  so that the tip of the bulge contacts the inner surface of the tubular  32 . Friction between the wall of the tubular  32  and flexible member  38 , coupled with the force directed to the flexible member  38  by the flange members  48 , generates a torque in the sidewall of the flexible member  38  causing the initial fold  53 . Further inward movement of the flange member  48  towards the opposing flange member  48  spirals the fold  53  within the wall of the flexible member  38  thereby forming the volute  38 A of  FIG. 6 . Optionally, the flexible member  38  can have a varying thickness to induce formation of the fold  53 . 
         [0036]    In  FIG. 9 , a sectional view is depicted of the flexible member  38  having a portion manipulated into a volute  38 A. In  FIG. 10 , an alternative flexible member  54  is shown in a sectional view having a volute  54 A made up of first and second rolls  51 ,  52 . In this example, the flexible member  54  has first and second openings  41 ,  42  at opposing ends and where the thickness of the flexible member  54  varies from adjacent the first opening  41  and the second opening  42 . By strategically adjusting the thickness of the flexible member  54  in this fashion, initial folds (not shown) can be formed to produce the first and second rolls  51 ,  52  as shown. 
         [0037]    The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims. In an example embodiment, disclosed is a bridge plug assembly for use in a tubular comprising, a mandrel, an annular flexible member circumscribing a portion of the mandrel and having first and second ends, an elongated continuous web member having a portion disposed between the flexible member and the mandrel that exits the flexible member at the first end of the flexible member, and an outer portion disposed in a space past an outer diameter of the flexible member and between the first and second ends of the flexible member, so that when the bridge plug assembly is inserted within a tubular and the outer portion is pulled in a direction away from the first end, the flexible member is inverted at the first end to form a volute that projects radially outward into the annular space between the mandrel and the tubular.