Abstract:
A system for use in a wellbore is disclosed. The system may include a tube, a swell packer surrounding a portion of the tube, a first pair of plates coupled to an outer surface of the tube and positioned at a first end of the swell packer, each of the first pair of plates having a plurality of slots extending inwardly from an outer edge of the plate, the regions between slots defining petals, wherein at least one of the slots of one of the first pair of plates overlaps with at least one of the petals of the second of the first pair of plates, and a second pair of plates coupled to the outer surface of the tube and positioned at a second end of the swell packer, each of the second pair of plates having a plurality of slots extending inwardly from an outer edge of the plate, the regions between slots defining petals wherein at least one of the slots of one of the second pair of plates overlaps with at least one of the petals of the second of the second pair of plates.

Description:
BACKGROUND 
       [0001]    Hydrocarbon fluids such as oil and gas are found in subterranean portions of geological formations or reservoirs. Wells are drilled into these formations for extracting the hydrocarbon fluids. Wells may be completed in a variety of ways including open hole and cased hole configurations. The processes involved in completing well bores and producing hydrocarbons from them often require isolation of one or more zones from another. For example, the well bore may pass through multiple production zones. In these applications, it may be desireable to isolate the non-productive regions located between the production zones. In particular, the annular region on a well bore disposed between the well bore wall (or casing) and the string may need to be isolated. 
         [0002]    A variety of packers have been developed to isolate such regions. For example, mechanical, inflatable, chemical and pneumatic packers may be used. Such packers may respond to hydraulic pressure by expanding to fill the annulus. Swell rubber packers have been used that rely on an elastomeric material such as rubber and its tendancy to swell in presence of hydrocarbons. Such packers have been disclosed in U.S. Pat. Publication No. 2007/0151723 by Freyer. These packers expand to fill an annulus when comes in contact with the wellbore fluids and have the advantage of not relying on separate actuation means or moving parts. 
         [0003]    When the elastomer comprising the swell packer expands, the mechanical properties of the elastomer deteriorate and the packer weakens. As a result, the elastomer becomes prone to failure when exposed to high differential pressures. This may result in extrusion of the elastomer along the pressure gradient and the loss of the annular seal. 
         [0004]    Accordingly, some packers have been provided with rigid, solid collars or rings placed at either end of the swell packer. Such devices may not reliably prevent extrusion as the variable diameter of a well bore may leave room between the collar and the wellbore wall that could allow for a portion of the elastomer to be extruded into the anular region above or below the packer. Also, such solid collars limit the ability to deploy intelligent completions devices such as fiber optic lines, wirelines, communications devices, sensors, and other such devices as the solid collar does not allow for deployment of such devices through the annular region. 
         [0005]    Accordingly, there is a need for an anti-extrusion device for a swell packer that may reliably fill the annular region and prevent or limit extrusion under relatively high differrential pressures. There is also a need for an anti extrusion device that is capable of use while deploying intelligent well completions devices in conjunction with a swell packer. 
       SUMMARY 
       [0006]    Some embodiments relate to a system for use in a wellbore. The system may comprise a tube, a swell packer surrounding a portion of the tube, a first pair of plates coupled to an outer surface of the tube and positioned at a first end of the swell packer, each of the first pair of plates having a plurality of slots extending inwardly from an outer edge of the plate, the regions between slots defining petals, wherein at least one of the slots of one of the first pair of plates overlaps with at least one of the petals of the second of the first pair of plates, and a second pair of plates coupled to the outer surface of the tube and positioned at a second end of the swell packer, each of the second pair of plates having a plurality of slots extending inwardly from an outer edge of the plate, the regions between slots defining petals wherein at least one of the slots of one of the second pair of plates overlaps with at least one of the petals of the second of the second pair of plates. 
         [0007]    Other embodiments relate to a system for use in a wellbore comprising a tube, a swell packer surrounding a portion of the tube, a first pair of plates coupled to an outer surface of the tube and positioned at a first end of the swell packer, each of the first pair of plates having a plurality of slots extending inwardly from an outer edge of the plate, the regions between slots defining petals, wherein at least one of the slots of one of the first pair of plates overlaps with at least one of the petals of the second of the first pair of plates, and a second pair of plates coupled to the outer surface of the tube and positioned at a second end of the swell packer, each of the second pair of plates having a plurality of slots extending inwardly from an outer edge of the plate, the regions between slots defining petals wherein at least one of the slots of one of the second pair of plates overlaps with at least one of the petals of the second of the second pair of plates. A passage through the first pair of plates, the second pair of plates, and the swell packer may be provided, and a second tube disposed within the channel. 
         [0008]    Yet other embodiments relate to a system for use in a well bore comprising a tube, and a swell packer surrounding a portion of the tube. A first anti-extrusion device may be disposed at a first end of the swell packer and a second anti-extrusion device disposed at a second end of the swell packer. A passage through the first anti-extrusion device, the swell packer and the second anti extrusion device may be provided and a communication line disposed within the passage. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a cross sectional view of a system for use in a wellbore. 
           [0010]      FIG. 2  is an end view of plates for use in the wellbore system of  FIG. 1  taken along line  2 - 2 . 
           [0011]      FIG. 3  is a cross sectional view of a system for use in a wellbore. 
           [0012]      FIG. 4  is an end view of plates for use in the wellbore system of  FIG. 3  taken along line  4 - 4 . 
           [0013]      FIG. 5  is a cross sectional view of a system for use in a wellbore. 
           [0014]      FIG. 6  is an elevation view of plates for use in the wellbore system of  FIG. 5  taken along line  6 - 6   
           [0015]      FIG. 7  is a cross sectional view of a system for use in a wellbore. 
           [0016]      FIG. 8  is a cross sectional view of a system for use in a wellbore. 
           [0017]      FIG. 9  is an elevation view of plates for use in the wellbore system of  FIG. 8  taken along line  9 - 9 . 
           [0018]      FIG. 10  is a cross sectional view of a system for use in a wellbore. 
           [0019]      FIG. 11  is an elevation view of plates for use in the wellbore system of  FIG. 10  taken along line  11 - 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Referring to  FIGS. 1 and 2 , a system  10  comprises a string  12 , shown as a production tube, swell packer  14 , and plates  16 . Swell packer  14  may comprise an elastomeric material that will expand in the presence of hydrocarbons or specific fluid. Swell packer  14  is positioned along an outer surface of string  12  such that packer  14  is disposed between string  12  and a wall  18  to provide a flow region  20  and an annular region  22 . When placed in or near a production zone, a portion of the hydrocarbons therein may be absorbed and cause swell packer  14  to expand and seal the annular region. Wall  18  may be a cement or other casing or may be the wall of an open hole. Coupler  24  may be used in conjunction with plates  16 . Coupler  24  extends through a first set of plates, through the swell packer  14  and through the second set of plates. The coupler may be a rod and may be secured at a first end with a head  26  and at a second end with a fastener  28 . Coupler  24  may be tensioned to resist movement of plates  16  along string  12  as packer  14  swells. 
         [0021]      FIG. 2  shows two types of plates  16   a  and  16   b  that may be used to provide an extrusion barrier. Each of plates  16   a  and  16   b  include a plurality of petals  30 . Each petal is positioned adjacent two slots  32 . The petals are angled towards swell packer  14  from a deflection point  34 . Seals  36  may be provided in apertures  38  to prevent extrusion between plates  16  and couplers  24 . The position of apertures  38  relative to petals  30  may be varied such that the petals of plate  16   a  overlap the slots  32  of plate  16   b  and vice versa. The overlapping petals prevent extrusion of the elastomeric material through the slots  32 . When positioned down hole, swell packer  14  will contact hydrocarbons and expand to fill the annular region. Unlike rigid collars that have been used to bound the lateral expansion of the packer, petals  30  of plates  16  may be deflected outward towards wall  18 . This allows provides for a tight seal of the annular region and further restricts the extrusion of the elatomeric material. At least one of plates  16   a  and one of plates  16   b  are used at each end of swell packer  14 . In other embodiments additional plates may be used depending on the pressures that will be encountered. 
         [0022]    Referring to  FIGS. 3 and 4 , a system  110  comprises a string  112 , shown as a production tube, swell packer  114 , and plates  116 . Swell packer  114  may comprise an elastomeric material that will expand in the presence of hydrocarbons. Swell packer  114  is positioned along an outer surface of string  112  such that packer  114  is disposed between string  112  and a wall  118  to provide a flow region  120  and an annular region  122 . When placed in or near a production zone, a portion of the hydrocarbons therein may be absorbed and cause swell packer  114  to expand and seal the annular region. Wall  118  may be a cement or other casing or may be the wall of an open hole. Coupler  124  may be used in conjunction with plates  116 . Coupler  124  extends through a first set of plates, through the swell packer  114  and through the second set of plates. The coupler may be a rod and may be secured at a first end with a head  126  and at a second end with a fastener  128 . Coupler  124  may be tensioned to resist movement of plates  116  along string  112  as packer  114  swells. 
         [0023]      FIG. 4  shows two types of plates  116   a  and  116   b  that may be used to provide an extrusion barrier. Each of plates  116   a  and  116   b  include a plurality of petals  130 . Each petal is positioned adjacent two slots  132 . The petals are angled towards swell packer  114  from a deflection point  134 . Seals  136  may be provided in apertures  138  to prevent extrusion between plates  116  and couplers  124 . The position of apertures  138  relative to petals  130  may be varied such that the petals of plate  116   a  overlap the slots  132  of plate  116   b  and vice versa. The overlapping petals prevent extrusion of the elastomeric material through the slots  132 . When positioned down hole, swell packer  114  will contact hydrocarbons and expand to fill the annular region. Unlike rigid collars that have been used to bound the lateral expansion of the packer, petals  130  of plates  16  may be deflected outward towards wall  118 . This allows provides for a tight seal of the annular region and further restricts the extrusion of the elatomeric material. 
         [0024]    In each of plates  16 , a slot  140  is provided. In each of plates  16   a , a slot  140  is positioned where on e of slots  132  would normally be positioned. In some embodiments slot  140   a  may be the same size and shape as slots  130 . In other embodiments, as shown, slot  140   a  may be larger than one of slots  130 . In each of plates  16   b , slot  140   b  may be centered on a petal  130  relative to the arc of the petal, such that slots  140   a  and  140  line up to provide a passage  142  through the anti extrusion device. Tube  144  may be run through passage  142  to accommodate a communication line or other device. Cover  146  may be used to hold tube  144  in place relative to plate  16 . Cover  146  may comprise the same swelling elastomeric material as packer  114  thus providing a passage along the whole length of swell packer  114 . Alternatively, apertures may be provided in plates  16   a  and  16   b  to provide a passage. 
         [0025]    Referring to  FIGS. 5 and 6 , a system  210  comprises a string  212 , shown as a production tube, swell packer  214 , and plates  216 . Swell packer  214  may comprise an elastomeric material that will expand in the presence of hydrocarbons. Swell packer  214  is positioned along an outer surface of string  212  such that packer  14  is disposed between string  212  and a wall  218  to provide a flow region  220  and an annular region  222 . When placed in or near a production zone, a portion of the hydrocarbons therein may be absorbed and cause swell packer  214  to expand and seal the annular region. Wall  218  may be a cement or other casing or may be the wall of an open hole. Plates  216  may be positioned between swell packer  214  and couplers  248 . Couplers  248  are configured to resist lateral movement of pates  216  relative to mandrel  212   a . Couplers  248  may be threaded to mandrel  212   a  and tubing  212 .  FIG. 6  shows plate  216  that may be used to provide an extrusion barrier. Each of plates  216  include a plurality of petals  230 . Each petal is positioned adjacent two slots  232 . The petals are angled towards swell packer  214  from a deflection point  234 . Alternating plates  216  may be positioned such that the petals  230  of one plate  216  overlap with the slots  232  of the adjacent plate  216 . The overlapping petals prevent extrusion of the elastomeric material through the slots  232 . When positioned down hole, swell packer  214  will contact hydrocarbons and expand to fill the annular region. Unlike rigid collars that have been used to bound the lateral expansion of the packer, petals  230  of plates  216  may be deflected outward towards wall  218 . Alternately, a passageway and tube can be provided with same arrangement as shown in  FIG. 3 . 
         [0026]    Referring to  FIG. 7 , a system  310  comprises a string  312 , shown as a production tube, swell packer  314 , and plates  316 . Swell packer  314  may comprise an elastomeric material that will expand in the presence of hydrocarbons. Swell packer  314  is positioned along an outer surface of string  312  such that packer  314  is disposed between string  312  and a wall  318  to provide a flow region  320  and an annular region  322 . When placed in or near a production zone, a portion of the hydrocarbons therein may be absorbed and cause swell packer  314  to expand and seal the annular region. Wall  318  may be a cement or other casing or may be the wall of an open hole. Plates  316  may be positioned between swell packer  314  and couplers  348 . Couplers  348  are configured to resist lateral movement of pates  316  relative to mandrel  312   a . Couplers  350  may be threaded to mandrel  312   a  and tubing  312 . One or more of plates  316  positioned closes to swell packer  314  may be provided with extensions  356  which extend roughly parallel to tube  312  and extend from a deflection point  358 . Extensions  356  may serve to further reduce extrusion of the elastomer material past plates  316 . 
         [0027]    Referring to  FIGS. 8 and 9 , a system  410  comprises a string  412 , shown as a production tube, swell packer  414 , and plates  416 . Swell packer  414  may comprise an elastomeric material that will expand in the presence of hydrocarbons. Swell packer  414  is positioned along an outer surface of string  412  such that packer  414  is disposed between string  412  and a wall  418  to provide a flow region  420  and an annular region  422 . When placed in or near a production zone, a portion of the hydrocarbons therein may be absorbed and cause swell packer  414  to expand and seal the annular region. Wall  418  may be a cement or other casing or may be the wall of an open hole. Plates  216  may be positioned between swell packer  414  and couplers  460 . Couplers  460  are configured to resist lateral movement of pates  416  relative to tube  412 . An inner surface of couplers  46  contacts an outer surface of tube  412  at a region  462 . The region  462  may be knurled or otherwise textured to provide increased friction between couplers  460  and tube  412 . Couplers  460  comprise first half  460   a  and a second half  460   b . Second half  460   b  may be provided with recesses  462  to accommodate bolts  464  which may be used to secure first half  460   a  to second half  460   b . Alternatively, a single recess may be positioned on each half in which case the halves  460   a  and  460   b  could be identical. 
         [0028]    One or more of plates  416  positioned closes to swell packer  414  may be provided with extensions  456  which extend roughly parallel to tube  412  and extend from a deflection point  458 . Extensions  456  may serve to further reduce extrusion of the elastoomer material past plates  416 . 
         [0029]    Referring to  FIGS. 10 and 11 , a system  510  comprises a string  512 , shown as a production tube, swell packer  514 , and plates  516  and  517 . Swell packer  514  may comprise an elastomeric material that will expand in the presence of hydrocarbons. Swell packer  14  is positioned along an outer surface of string  512  such that packer  514  is disposed between string  512  and a wall  518  to provide a flow region  520  and an annular region  522 . When placed in or near a production zone, a portion of the hydrocarbons therein may be absorbed and cause swell packer  514  to expand and seal the annular region. Wall  518  may be a cement or other casing or may be the wall of an open hole. Plates  517  may be joined to plates  516  at a point near deflection point  534  of plate  516 . Plates  517  may be positioned on the side of plate  516  adjacent to the elastomer material. 
         [0030]    Plates  516  may include an extension  566  extending parallel to tube  512  and may be coupled to tube  512  by fastener  568 . Alternatively, plate  516  may be welded or otherwise coupled to tube  512 . Plate  516  also includes a lateral extension  556  which extends from a deflection point  558 . Plate  517  may extend roughly parallel to portion  570  of plate  516  and comprise an extension  557  that extends roughly parallel to extension  556  from deflection point  559 . Plate  516  includes petals  530  separated by slots  532 . Likewise, plate  517  includes petals  531  separated by slots  533 . Plates  516  and  517  are configured such that the petals of one plate overlap the slots of the other. 
         [0031]    Although the foregoing has been described with reference to exemplary embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope thereof. For example, although different example embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example embodiments or in other alternative embodiments. The present subject matter described with reference to the example embodiments and set forth in the following claims is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the claims reciting a single particular element also encompass a plurality of such particular elements. Many other changes and modifications may be made to the present invention without departing from the spirit thereof. The scope of these and other changes will become apparent from the appended claims. The steps of the methods described herein may be varied, and carried out in different sequences.