Abstract:
A packer that is usable with a well includes a resilient seal element and a support member. The resilient seal element is adapted to radially expand in response to the longitudinal compression of the element. The support member is at least partially surrounded by the seal element and is adapted to radially expand with the seal element to support the element. The support sleeve is substantially harder than the seal element.

Description:
[0001]     This application claims the benefit pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 60/595,997 entitled, “PACKER ELEMENT WITH SUPPORT,” filed on Aug. 23, 2005, which is hereby incorporated in reference in its entirety. 
     
    
     BACKGROUND  
       [0002]     The invention generally relates to a packer.  
         [0003]     Hydrocarbon fluids, such as oil and natural gas, are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids. After the well has been completed, production of oil and gas can begin.  
         [0004]     In such well completion operations, packers are used to prevent fluid flow through an annulus formed by a tubing within the well and the wall of the wellbore or a casing. The packer is generally integrally connected to the tubing, using, for example, means such as a threaded connection, a ratch-latch assembly, or a J-latch, all of which are well known in the art. The tubing/packer connection generally establishes the seal for the inner radius of the annulus. The seal for the outer radius of the annulus is generally established by a deformable element such as rubber or an elastomer. A compressive force is generally applied to the deformable element, causing it to extrude radially outward. The element extends from the outer portion of the packer to the wellbore wall or casing and seals between those structures.  
       SUMMARY  
       [0005]     In an embodiment of the invention, a packer that is usable with a well includes a resilient seal element and a support member. The resilient seal element is adapted to radially expand in response to the longitudinal compression of the element. The support member is at least partially surrounded by the seal element and is adapted to radially expand with the seal element to support the element. The support sleeve is substantially harder than the seal element.  
         [0006]     In another embodiment of the invention, a technique that is usable with a well includes compressing a resilient seal element to cause the seal element to radially expand. The technique includes in concert with the radial expansion of the seal element, deforming a material that is substantially harder than the seal element to support the seal element.  
         [0007]     Advantages and other features of the invention will become apparent from the following drawing, description and claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0008]      FIG. 1  is a schematic diagram of a well according to an embodiment of the invention.  
         [0009]      FIG. 2  is a schematic diagram depicting a seal assembly of the packer of  FIG. 1  according to an embodiment of the invention.  
         [0010]      FIG. 3  depicts the seal assembly when the packer is set according to an embodiment of the invention.  
         [0011]      FIGS. 4, 5 ,  6  and  7  depict seal assemblies according to other embodiments of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0012]     A packer is a device that is used in an oilfield well to form a seal for purposes of controlling production, injection or treatment. The packer is lowered downhole into the well in an unset state, and once in the appropriate position downhole, the packer is set, which means a seal of the packer radially expands to seal off an annular space. As an example, for a mechanically-set packer, a tubular string that extends from the surface to the packer may be moved pursuant to a predefined pattern to set the packer. For a hydraulically-set packer, fluid inside the tubular string may be pressurized from the surface, to create a tubing pressure differential to set the packer.  
         [0013]     In its set state, the packer anchors itself to the casing wall of the well (or to the wellbore wall in an uncased or open well) and forms a seal in the annular region between the packer and the interior surface of the casing wall. This seal subdivides the annular region to form an upper annular region above the packer that is sealed off from a lower annular region below the packer. The packer also forms a seal for conduits that are inserted through the packer between the upper and lower annular regions. As examples, one of these conduits may communicate production fluid from a production zone that is located below the packer, one of the conduits may communicate control fluid through the packer, one of the conduits may house electrical wiring for a submersible pump, allow production or injection through two different reservoir zones, and so forth.  
         [0014]      FIG. 1  depicts a well  10  (a subterranean or subsea well) that includes a packer  20  in accordance with an embodiment of the invention. The packer  20  may be connected to a tubular string  16  that extends downhole into the well. The packer  20  forms an annulus seal with the interior surface of a wall of a casing string  12  that circumscribes the packer  20  and lines a wellbore  11 . The wellbore  11  may be uncased in some embodiments of the invention. Additionally, the wellbore  11  may be a vertical or a lateral wellbore, depending on the particular embodiment of the invention.  
         [0015]     The packer  20  includes at least one seal assembly  24  to form the annular seal and at least one set of slips  22  to anchor the packer  20  to the casing string  12 . In this manner, when run into the well, the seal assembly  24  and the slips  22  are radially retracted to allow passage of the packer  20  through the central passageway of the casing string  12 . However, when the packer  20  is in the appropriate downhole position, the packer  20  is set to place the packer  20  in a state in which the seal assembly  24  and slips  22  are radially expanded. When radially expanded, the slips  22  grip the interior surface of the wall of the casing string  12  to physically anchor the packer  20  in position inside the well. The radial expansion of the seal assembly  24 , in turn, seals off the annular space between the string  16  and the casing string  12  to form a sealed annular region above the seal assembly  24  and a sealed annular region below the seal assembly  24 .  
         [0016]     In some embodiments of the invention, the packer  20  may be hydraulically-actuated for purposes of controlling the packer  20  from the surface of the well to set the packer  20 . This means that pressure may be communicated through fluid inside the string  16  to the packer  20 . In response to this pressure reaching a predefined threshold level, pistons (not shown in  FIG. 1 ) move to radially expand the slips  22  and apply compressive forces on the seal assembly  24  to radially expand the assembly  24 . A retention mechanism of the packer  20  serves to hold the packer  20  in the set state when the pressure that is used to set the packer  20  is released.  
         [0017]     One or more mandrels  21 , or tubular members, may extend through the packer  20  for purposes of providing communicating paths through the packer  20 . Depending on the particular application of the packer  20 , a particular mandrel  21  may contain one or more communication paths, such as paths to communicate production fluid, electrical lines, or control fluid through the packer  20 . For example, in a particular application, a single mandrel  21  may extend through the packer  20  for purposes of communicating production fluid from a tubular string  23  located below the packer  20  to the string  16  located above the packer  20 . However, in other applications, more than one mandrel  21  may be extended through the packer  20 . Thus, one mandrel  21  may be used for purposes of communicating electrical or hydraulic lines, for example, and another mandrel  21  may be used for purposes of communicating production fluid through the packer  20 .  
         [0018]     The packer  20  may be retrievable, and thus may include a release mechanism that when engaged, releases the retention mechanism of the packer  20  to radially retract the slips  22  and seal assembly  24  to permit retrieval of the packer  20  to the surface of the well.  
         [0019]     The packer  20  establishes two general seals: an interior seal between the interior of the packer  20  and the exterior of the one or more mandrels  21  that are extended through the packer  20  and an exterior seal between the exterior of the packer  20  and the interior surface of the wall of the casing string  12  (or the wellbore wall in alternative embodiments). The seal assembly  24  includes a resilient seal element (such as one or more elastomer or rubber sleeves, or rings) for establishing the seal between the packer exterior and the casing  12  (or wellbore wall).  
         [0020]     In general, as the requirements for packer designs tend towards larger and larger inner diameters through the packer, the annular seal element of the packer is forced to become thinner and thinner. Additionally, there may also desire to cover multiple casing weights with one size of packer, leading to larger gaps that must be bridged off by the annular seal element. Bridging off a large gap with a thin element may be very difficult, unless the rubber is supported. Embodiments of the invention that are described herein include a packer that has a resilient seal element, which has a support that is fabricated from a hardened material.  
         [0021]     In the context of this application, a “hardened material” means a material that has a substantially greater resistance to deformation relative to the seal element of the packer. For example, in some embodiments of the invention, the hardened material may be a metal that has substantially more resistance to deformation than an elastomer or rubber material that forms the seal element. Alternatively, in accordance with other embodiments of the invention, the hardened material may be a composite or plastic material, which has substantially more resistance to deformation that an elastomer or rubber material that forms the seal element. Furthermore, in accordance with other embodiments of the invention, the hardened material may be a combination of the above-mentioned materials. Thus, many variations are contemplated and are within the scope of the appended claims.  
         [0022]     As a more specific example, for some embodiments of the invention, the hardened material is a soft metal, such as low carbon steel or copper, in accordance with some embodiments of the invention. However, in accordance with other embodiments of the invention, the hardened material may be a relatively resilient material. For example, in accordance with some embodiments of the invention, the hardened material may be a metallic spring material. Thus, many variations are possible and are within the scope of the appended claims.  
         [0023]      FIG. 2  depicts a more detailed section  50  (see  FIG. 1 ) of the packer  20  in accordance with some embodiments of the invention. As shown in  FIG. 2 , the packer  20  includes sleeves, or gages  54  and  55  (also called “thimbles”), which are designed to longitudinally compress the seal assembly  24  (which is disposed in between) to radially expand the assembly  24  when the packer  20  is set. It is noted that  FIG. 2  depicts the packer  20  in its unset state.  
         [0024]     In general, the seal assembly  24  includes a resilient seal element that may be formed from multiple seal sleeves, or rings, such as upper  56 , middle  60  and lower  64  seal rings. The seal rings  56 ,  60  and  64  generally circumscribe the inner mandrel  16  of the packer  20  and may be formed from a rubber or an elastomer material (as examples). It is noted that the seal assembly  24  may include fewer or more seal rings, depending on the particular embodiment of the invention.  
         [0025]     As also depicted in  FIG. 2 , the seal assembly  24  may include upper  88  and lower  90  metallic shoes for purposes of minimizing the longitudinal extrusion of the seal element  24  when the packer  20  is set. In the packer&#39;s unset state, the upper shoe  88  generally conforms to the upper edge of the seal ring  56  and is located between the upper edge of the seal ring  56  and the upper gage  54 ; and the lower shoe  90  generally conforms to the lower edge of the lower seal ring  64  and is located between this lower edge and the lower gage  55 .  
         [0026]     In addition to the resilient seal element, the seal assembly  24  includes a hardened (relative to the seal rings  56 ,  60  and  64 ) support sleeve  80  that is located between the resilient seal element and the mandrel  16 . As a more specific example, as depicted in  FIG. 2 , in some embodiments of the invention, the support sleeve  80  may be located (as an example) between the middle seal ring  60  and the outer surface of the mandrel  16 . The support sleeve  80 , which may have a substantially thinner radial thickness than the middle seal ring  60  (before the packer  20  is set), is designed to be radially expanded (and deformed) with the seal rings  56 ,  60  and  64  so that the sleeve  80  supports the seal rings  56 ,  60  and  64  in their radially-expanded states. Although  FIG. 2  depicts the support sleeve  80  as being located radially inside the middle seal ring  60 , in accordance with other embodiments of the invention, the support sleeve  80  may longitudinally extend inside all or part of the upper  56  and lower  64  seal rings (as another example). Therefore, many variations are possible and are within the scope of the appended claims.  
         [0027]     The support sleeve  80  may or may not be bonded to the middle seal ring  60 , depending on the particular embodiment of the invention. For embodiments of the invention in which the support sleeve  80  is bonded to the middle seal ring  60 , all or only part of the outer surface of the support sleeve  80  may be bonded to the inner surface of the middle seal ring  60 . It is noted that depending on the particular embodiment of the invention, the support sleeve  80  may be bonded to all, part or none of the upper  56  and lower  64  seal rings.  
         [0028]     In some embodiments of the invention, the support sleeve  80  includes an annular crimped section  82  at its longitudinal midpoint, which radially extends away from the outer surface of the mandrel  16 . The crimped section  82  configures the support sleeve  80  to bend at the section  82  during the radial expansion of the seal assembly  24 , as depicted in  FIG. 3 , which shows a section  95  of  FIG. 2  when the packer  20  is set. Referring to  FIG. 3 , in the radially expanded state of the seal assembly  24 , the seal rings  56 ,  60  and  64  are radially expanded and deformed to at least partially contact the inner surface of the casing  12 . As also shown in  FIG. 3 , the support sleeve  80  is also radially expanded and deformed to support the seal rings  56 ,  60  and  64 . The shoes  88  and  90  minimize longitudinal extrusion of the seal element, in this state of the packer  20 .  
         [0029]     Referring back to  FIG. 2 , in accordance with some embodiments of the invention, the region between the inner surface of the crimped section  82  and the outer surface of the mandrel  16  may be a void space. However, in accordance with other embodiments of the invention, this space may be filled with a seal element that partially or totaling conforms to the boundaries of the space before the packer  20  is set.  
         [0030]      FIG. 4  depicts an exemplary section  100  of another packer in accordance with another embodiment of the invention. The section  100  is to be compared to the corresponding section  95  of the packer  20 . In general, the packer has the same overall design as the packer  20 , except the seal assembly of this packer includes a single seal ring  124  (made from elastomer or rubber, for example) and an inner o-ring  110  behind a support sleeve  112  (made from a hardened material relative to the seal ring  124 ). The support sleeve  112  extends over the entire inner surface of the seal ring  124 . The support ring  112  also includes a crimped section  114  that, in the unset state of the packer  20 , radially extends away from the outer surface of the mandrel  16 . The crimped section  114  creates a void  116  that receives the o-ring seal  110 . Other seals may be located inside the space  116 , in accordance with other embodiments of the invention.  
         [0031]     Referring to  FIG. 5 , in accordance with other embodiments of the invention, another packer, which is illustrated by an exemplary section  150  (to be compared to sections  95  and  100 ), includes expandable rings  160  and  178  that are located between the gages and a single seal ring  190 . More specifically, an upper expandable ring  160  is located between an upper gage  154  and an upper edge of the seal ring  190 . The upper gage  154  may include a sloped, or beveled, surface  156  for purposes of slidably engaging with the upper expandable seal ring  160 . Likewise, a lower expandable seal ring  178  may be located between a lower gage  164  and the lower surface of the seal ring  190 . Similar to the upper gage  154 , the lower gage  164  includes a sloped, or beveled, surface  166  for purposes of slidably engaging the lower expandable ring  178 .  
         [0032]     As also shown in  FIG. 5 , the packer includes a support sleeve  180  (made from a hardened material) that extends over the entire surface of the seal ring  190  for purposes of providing support to the ring  190  for the set state of the packer. The seal ring  180  includes a crimped section  182  that is predisposed to cause the support ring  180  to radially expand at the section  182  during the setting of the packer, similar to the support rings  80  and  112  that are described above.  
         [0033]     As yet another variation,  FIG. 6  depicts an exemplary section  200  of a packer in accordance with another embodiment of the invention. As shown, the packer includes garter springs that are located between the gages and the seal assembly. More specifically, an upper garter spring  210  is located between an upper gage  202  and the upper edge of a seal ring  230 . A lower garter spring  212  is located between the upper edge of a lower gage  220  and the lower edge of the seal element  230 . Additionally, the packer includes a support sleeve  232  (made from a hardened material) that is located over the entire inner surface of the seal ring  230  between the seal ring  230  and the outer surface of the mandrel  16 ; and the sleeve  232  includes a crimped portion  234  to predispose the sleeve  232  to radially expand at the section  234  during the setting of the packer.  
         [0034]     As yet another example,  FIG. 7  depicts an exemplary section  250  of a packer in accordance with another embodiment of the invention. The section  250  is similar to the section  50  (see  FIG. 2 ) (with like reference numerals being used), with the following differences. In particular, the packer includes support rings  260  and  270  that are located at the ends of the seal assembly  24  for purposes of minimizing longitudinal extrusion of the packer&#39;s seal element. The support ring  260  is located between the upper shoe  88  and the upper gage  54 ; and the lower ring  270  is located between the lower gage  55  and the shoe  90 .  
         [0035]     Each of the rings  260  and  270  has a V-shaped cross-section and provides support to minimize longitudinal extrusion of the seal element (seal rings  56 ,  60  and  64 ) when the packer is set. More specifically, when the packer is set, the V-shaped rings  260  and  270  each flatten to be substantially horizontal and rise above the gauge diameter, thereby minimizing the extrusion gap and supporting the seal element.  
         [0036]     While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.