Abstract:
The invention discloses a patch for placement in a wellbore and associated methods. The patch has a longitudinal member and an anchor that is radially expanded to engage the wall of the borehole to secure the patch against axial and radial movement. The anchor is set using a running tool that radially expands the anchor and the longitudinal body. The anchor may include one or more elements that can be securely engaged within the wellbore. The longitudinal member and/or the anchor may include a sealing element to provide a seal between the wellbore inside and the earth formation surrounding the wellbore.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from U.S. Provisional Application Ser. No. 60/590,596 filed on Jul. 23, 2004, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates generally to devices and methods for securing a patch within a wellbore.  
         [0004]     2. Description of the Related Art  
         [0005]     Patches are used in uncased wellbores and wellbore sections to prevent collapse of the wellbore and/or preclude unintended fluid flow into or out of the wellbore. A patch is usually a tubular sleeve that is secured to the wall of the wellbore. The patch may be any desired length. The patch provides structural support and fluid sealing. There are two primary scenarios in which it is often desired to use a wellbore patch.  
         [0006]     The first scenario occurs during drilling of a wellbore, particularly through unconsolidated earth. Because the wellbore is not yet lined with a casing, drilling mud and other fluids may undesirably flow into the surrounding earth formations from the wellbore. This not only results in the loss of fluids, but might contaminate production formations. In such an instance, a patch would provide the fluid sealing needed to prevent this fluid loss.  
         [0007]     The second scenario occurs during production from an “open hole” wellbore, which lacks casing. In this situation, there is the danger that undesirable fluids, such as water, will migrate from the surrounding earth formation into the borehole. A patch could be placed along the wellbore in the area where fluid ingress occurs to block it.  
         [0008]     In order to function correctly, a patch is secured against axial and rotary movement within the wellbore. Running of a drill string, for example, into the wellbore and through the patch will result in torsional and axial forces being imparted to the patch. The patch might be cemented into place. However, this operation is time consuming as the cement needs to be given time to set and later cure. Also, a cleaning tool is assembled and run into the wellbore to clean the excess cement from the patched area once the cement has been placed in the wellbore.  
         [0009]     Currently there is not a relatively easy and acceptable method of securing a patch within a wellbore. The present invention addresses some of the above-noted problems of the prior art.  
       SUMMARY OF THE INVENTION  
       [0010]     The invention provides improved devices and methods for securing a patch within an open hole wellbore. The patch is provided with one of a number of types of anchors that is radially expanded to engage the wall of the borehole to secure the patch against axial and radial movement. The anchors are set using a swaging tool that radially expands anchor and the patch. The action of radially expanding the patch actuates the anchor.  
         [0011]     In one aspect, a patch for use within a wellbore comprises a generally cylindrical patch body that is radially expandable from a first, reduced diameter condition to a second, enlarged diameter condition, and an anchor portion that is radially expandable to bitingly engage the wellbore.  
         [0012]     In another aspect, a method of placing a patch in a wellbore having an internal dimension comprises positioning the patch at a selected location in the wellbore. The patch has a longitudinal body that is radially expandable and an associated anchor that is engageable to a wellbore wall. The anchor is engaged with the wellbore wall in a manner that enables the longitudinal body of the patch to remain at the selected location.  
         [0013]     The patch may be made from any suitable material and in any desired form. It may be a solid metallic member, a metallic longitudinal mesh, or a member made from a composite or hybrid material. The anchor may include one or more radially expandable member which can securely engage with the wellbore wall. The anchor is engaged with the borehole wall in a manner that will cause the longitudinal section to remain in the desired location in the wellbore. The longitudinal member and/or the anchor may be made from a suitable material, such as a rubber or another elastomeric material to provide seal between the wellbore well and the longitudinal member to prevent fluid flow between the formation and the earth formation surrounding the wellbore.  
         [0014]     Examples of the more important features of the invention have been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The advantages and further aspects of the invention will be 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:  
         [0016]      FIG. 1  is a side, cross-sectional view of an exemplary wellbore during drilling;  
         [0017]      FIG. 2  depicts the wellbore shown in  FIG. 1  subsequently being underreamed;  
         [0018]      FIG. 3  shows the wellbore of  FIGS. 1 and 2  now with a wellbore patch having been disposed therein by a running and setting tool;  
         [0019]      FIG. 4  shows the wellbore of  FIGS. 1-3  after the patch has been set within the wellbore;  
         [0020]      FIG. 5  illustrates subsequent running of a drilling string into the wellbore;  
         [0021]      FIG. 6  is side, cross-sectional view of a production wellbore showing a patch being set by a running and setting tool;  
         [0022]      FIG. 7  is a partial side cross-sectional view of a first, exemplary anchor portion, in accordance with the present invention, shown before setting;  
         [0023]      FIG. 8  is a partial, side cross-sectional view of the anchor portion shown in  FIG. 7 , now in a set position;  
         [0024]      FIG. 9  is an end view of the anchor portion shown in  FIGS. 7 and 8 ;  
         [0025]      FIG. 10  is a partial, side cross-sectional view of an alternative exemplary anchor portion before setting;  
         [0026]      FIG. 11  is a partial, side cross-sectional view of the anchor portion shown in  FIG. 10  after setting;  
         [0027]      FIG. 12  is a partial, side cross-sectional view of a further alternative anchor portion in an unset condition;  
         [0028]      FIG. 13  depicts the anchor portion of  FIG. 12  now in a set condition;  
         [0029]      FIG. 14  is an axial cross-section of the anchor portion shown in  FIGS. 12 and 13 ;  
         [0030]      FIG. 15  is a partial, side cross-sectional view of a further alternative anchor portion in an unset position;  
         [0031]      FIG. 16  shows the anchor portion of  FIG. 15  now in a set position;  
         [0032]      FIG. 17  is a partial, side cross-sectional view of a further alternative anchor portion in an unset position; and  
         [0033]      FIG. 18  shows the anchor portion of  FIG. 15  in a set position.  
         [0034]      FIG. 19  shows a cone or swaging tool that is for use in enlarging the patch in retracted position.  
         [0035]      FIG. 20  shows the swaging tool of  FIG. 19  after activation in an enlarged position.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]      FIGS. 1-5  depict an exemplary wellbore  10  that has been drilled through the earth  12 . The wellbore  10  is an open hole wellbore that lacks casing. The surrounding earth  12  contains a permeable zone  16  into which drilling fluids might flow during the drilling operations. It is desired to seal the zone  16  off from fluid communication with the wellbore  10 .  FIG. 1  depicts a drill string  18  disposed within the wellbore  10  for initial drilling of the wellbore  10 . The drill string  18  includes a tubing that may be made of interconnected drill pipe members  20 , and a drill bit  22  at the lower end. As those of skill in the art understand, during drilling, drilling mud (not shown) is pumped down the string of drill pipe members  20 , flows out of the drill bit  22  and returns up the annulus  23  to the surface of the wellbore  10 . In this situation, it is desired to prevent the drilling mud from escaping into the permeable zone  16  by setting a patch within the wellbore  10 . To accomplish this, an underreaming tool  24 , of a type known in the art, is deployed, as shown in  FIG. 2 , to radially enlarge the section of wellbore proximate the permeable zone  16 . The underreamer  24  cuts a radially enlarged wellbore portion  26 .  
         [0037]     Once underreaming has been done, the drill string  18  is withdrawn from the wellbore  10 , and a patch  30  is disposed into the wellbore  10 , as  FIG. 3  illustrates. In  FIG. 3 , the patch  30  is in a radially reduced configuration. The patch  30  itself has a patch body  31  that includes a tubular section of radially expandable metal or other material. The patch body may be a solid tubular or a mesh. The patch body  31  is typically fashioned of a highly ductile material, such as annealed steel, but may be made for any suitable alloy or a non-metallic or by hybrid material. As noted previously, the patch  30  may be made to any suitable length. In this case, the length of the patch  30  is chosen to ensure complete coverage and fluid sealing across the permeable zone  16 . The patch  30  includes an associated anchor or anchor portion, shown schematically at  34 . Various configurations for the anchor portion  34  are described in detail later. The anchor portion  34  is shown to be located proximate the upper axial end  36  of the patch  30 . Alternatively, it should be understood that the anchor portion might, in fact, be located at any point along the axial length of the patch  30 . If desired, additional anchor portions  38  may also be incorporated into the patch  30 . The purpose of the anchor portions  34 , and  38  is to engage the uncased wall of the wellbore  10  and to secure the patch against axial and radial movement with respect to the wellbore  10 .  
         [0038]     The patch  30  is run into the wellbore  10  by a running and setting tool  40 . The exemplary running and setting tool  40  shown in  FIGS. 3 and 4  is suspended by coiled tubing  42 , but may be run into the wellbore  10  using a drill pipe or other suitable conveying member known in the art. The running and setting tool  40  includes an engagement shoe  44  at its lower end, upon which the patch  30  rests. Piston  46  and expansion swaging tool  48  are driven by a hydraulic pump  50 . Hydraulic fluid may be supplied to the pump  50  from the surface through tubing  42 . The running and setting tool  40  may comprise a catEXX™ brand tool, which is available commercially from Baker Oil Tools of Houston, Tex. To set the patch  30  within the wellbore  10 , the piston  46  and swaging tool  48  are driven downwardly through the patch  30 , radially enlarging it and bringing the anchor portions  34 , 38  into engaging contact with the wall of the wellbore  10 .  
         [0039]      FIG. 4  illustrates the patch  30  after it has been expanded radially, forcing the anchor portions  34  and  38  to engage the wall, thus securing the patch  30  to the wall of the wellbore  10 . With the patch  30  set, the running and setting tool  40  maybe withdrawn from the wellbore  10 . Subsequently, as  FIG. 5  illustrates, a drill string  18  may be reintroduced to the wellbore  10  and the wellbore drilled to a greater depth.  
         [0040]     It should be noted that the inside dimensions or the internal diameter of the patch body may be expanded to any desired dimension. The internal diameter may be the same less than or greater than the diameter of the wellbore  10  above or below the enlarged section  20 .  
         [0041]      FIG. 6  illustrates the setting of a patch  30  in a producing wellbore  60 . The wellbore  60  has been partially lined with casing  62  and has an uncased portion  64 . A water layer  66  is present in the surrounding earth  68 , and water from the layer  66  is undesirably entering the wellbore  60 . In  FIG. 6 , the production assembly (not shown) has been removed from the wellbore  60  so that a patch  30  may be set within. The patch  30  has been lowered into the wellbore  60  on a running and setting tool  40 , and is shown during the setting process. Once expanded and set, member  34  of the patch  30  creates a fluid seal at  31 , as described later, within the wellbore  60  so that an undesirable fluid, such as water from the layer  66  no longer enters the wellbore  60 . Following setting of the patch  30 , the running and setting tool  40  is removed from the wellbore  60  and the production assembly (not shown) can be reintroduced to the wellbore  60  to continue production.  
         [0042]     Turning now to  FIGS. 7-9 , there is illustrated a first exemplary anchor assembly  70  which may be used as the anchor portion  34  or  38  on patch  30 . The anchor assembly  70  includes a generally cylindrical body member  72  fashioned of a deformable metal or other material. The body member  72  may actually be a portion of the body of the patch  30 . A radially reduced channel  74  is formed into the member  72 . A plurality of engagement teeth  76  are affixed to the member  72  within the channel  74 . Preferably, the teeth  76  are radially spaced about the circumference of the member  72 , as shown in  FIG. 9 .  
         [0043]     During running in, the anchor portion  70  is in the position shown in  FIG. 7 . When set by the running and setting tool  30 , the swaging tool  48  deforms the channel  74  outwardly, so that the body member  72  assumes the shape shown in  FIG. 8 . Deformation of the channel  74  also urges the teeth  76  into biting engagement with the wall of the surrounding wellbore  10 , 60 . This biting engagement secures the patch  30  within the wellbore against axial and rotational movement. If desired, the channel  74  may be omitted altogether, and the teeth  76  brought into biting engagement with the wall of the wellbore  10 ,  60  merely by radial expansion of the body member  72  via the swaging tool  48 .  
         [0044]      FIGS. 10-11  depict an alternative anchor portion  80  which includes a tubular body member  82  with a plurality of malleable engagement strips  84  secured thereto. Preferably, the engagement strips  84  are disposed in a circumferentially spaced arrangement about the body member  82  in same manner as teeth  76  were. Each of the engagement strips  84  has a pair of axial ends  86 ,  88  that are welded or otherwise securely affixed to the outer surface of the member  82 . Each strip also features a central portion  90  that is unaffixed to the member  82 . In the unset position, shown in  FIG. 10 , the strips  84  are in a substantially linear, unbent condition.  
         [0045]     Setting of the anchor portion  80  relies upon the fact that the patch  30 , and anchor portion  80 , become axially shorter as it is expanded radially. When the swaging tool  48  is urged through the anchor portion  80 , the axial shortening of the body member  82  causes the ends  86 ,  88  of each engagement strip  84  to be moved closer together resulting in the strips  84  bowing outwardly as  FIG. 11  depicts. This outward bowing, together with the radial enlargement of the diameter of anchor portion  80  brings the engagement strips  84  into biting engagement with the wall of the wellbore  10 ,  60 .  
         [0046]      FIGS. 12-14  illustrate a further alternative exemplary anchor portion  92  that features a generally cylindrical body member  94  which has a number of longitudinal slots  96  cut therein. As the cross-sectional view of  FIG. 14  illustrates, the slots  96  define a set of body strips  98  therebetween.  FIGS. 12 and 14  depict the anchor portion  92  prior to its being set. When the swaging tool  48  is run through the patch  30 , axial shortening of the body member  94  will cause the strips  98  to bow outwardly, as  FIG. 13  shows, thereby bringing them into biting engagement with the wall of the wellbore  10 ,  60 .  
         [0047]      FIGS. 15-16  illustrate yet a further alternative anchor portion  100 . The anchor portion  100  has a body member  102  with an upper slotted portion  104 . The slotted portion  104  includes a plurality of longitudinal slots  106  that define engagement fingers  108  therebetween. Each of the fingers  108  preferably includes an outwardly projecting engagement lip  110 . In the unset position, shown in  FIG. 15 , the fingers  108  extend in the axial direction. However, the swaging tool  48  causes the fingers  108  to bend outwardly, as depicted in  FIG. 16  so that they are brought into engagement with the wall of the wellbore  10 ,  60 .  
         [0048]      FIGS. 17 and 18  depict still a further alternative anchor portion  120 . Anchor portion  120  includes a generally cylindrical body member  122  that features an outwardly protruding stop ledge  124 . A C-ring  126  surrounds the body member  122  and is located above the stop ledge  124 . A sloped face  128  also projects outwardly from the body member  122  and is located above the C-ring  126 .  FIG. 17  shows the anchor portion  120  in an unset position. In this position, the sloped face  128  is just above the C-ring  126 . When the swaging tool  48  is pushed through the anchor portion  120 , the body member  122  becomes axially shortened, causing the sloped face  128  to be moved closer to the stop ledge  124 . The sloped face  128  then urges the C-ring radially outwardly, as shown in  FIG. 18 , and into engagement with the wall of the borehole  10 ,  60 .  
         [0049]     The anchor also may be made wherein one member moves linearly to cause another member to move out radially to engage the wellbore. The linearly moveable member may be hydraulically operated as noted above or may be mechanically operated or by a combination thereof.  
         [0050]     It is noted that the anchor portions described above might be made from or coated or covered with rubbery elastomer, alloy or another sealing material, to provide a fluid sealing capability as well as biting engagement of the wall of the wellbore  10 ,  60 . Additionally, components making up the anchor portions might be fashioned from shape memory material, either metal or composite, the material making up the anchor portion might be initially formed into the set position. The memory effect provided by the material would increase the anchoring effect.  
         [0051]      FIG. 19  shows a retrievable tool  140  for use in enlarging the patch. The tool  140  includes a mandrel  150  that can be run into the wellbore. A radially expandable swage  150  is disposed around the mandrel  150  between a shoulder member  152  and a linearly movable member  156  to radially enlarge or expand the swage  152 , the member  156  is moved linearly toward the swage which moves a force application member  158  toward the swage, causing the swage  152  to move radially outwards as shown in  FIG. 20 . The member  156  may be moved hydraulically or mechanically or by any other suitable mechanism to retrieve the tool  140  from the wellbore. The member  156  is moved away from the swage  152  which allows the swage  152  to retract. The linear motion of the member  156  controls the rate and the extent of the radial movement of the member  152 .  
         [0052]     For the sake of clarity and brevity, descriptions of most threaded connections between tubular elements, elastomeric seals, such as o-rings, and other well-understood techniques are omitted in the above description. 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 one 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.