Abstract:
A torque anchor for anchoring well equipment in a well conduit to arrest movement in both longitudinal directions and rotation in a first direction, but not rotation in an opposed second direction. A mandrel connected to the equipment has one or more grooves for slideably receiving respective pins from a drag body on the mandrel. A slip cage on the mandrel houses slips for selectively engaging and disengaging the conduit. Manipulation of the mandrel at surface causes the pins to move within the one or more grooves on the mandrel and the drag body to move toward the slip retainer driving the slips outward to grip the conduit. Further pulling at surface maintains the set position. The anchor is unseta surface by releasing the pull, rotating the mandrel in the second direction, and pushing the mandrel to disengage the slips.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from Canadian Patent Application No. 2,854,409 filed Jun. 14, 2014 entitled Quarter Turn Torque Anchor and Catcher. This application is also a continuation-in-part of United States patent application Ser. No. 14/311,322 filed Jun. 22, 2014 and entitled Quarter Turn Torque Anchor and Catcher, which is itself a continuation-in-part of U.S. patent application Ser. No. 13/716,075 filed on Dec. 14, 2012 and entitled Quarter Turn Tension Torque Anchor. The entire disclosures of these priority documents and all related applications or patents are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to tools for petroleum wells generally, including wells accessing heavy crude. In particular, the present invention relates to a tubing anchor catcher and its use in a system for reducing movement, which may be caused by a downhole pump, within in a well conduit. 
       BACKGROUND OF THE INVENTION 
       [0003]    A tubing string is used within a petroleum well to position downhole tools proximal to one or more underground geological formations that contain petroleum fluids of interest. The tubing string may also be referred to as production tubing or a production string. The tubing string is made up of sections of individual pipe joints that are typically threadedly connected to each other. The tubing string extends within a bore of the well. The well bore is typically completed with casing or liners. The completed well bore may also be referred to as a well conduit. The tubing string can carry various downhole tools into the well conduit. For example, downhole tools can be used for various purposes including anchoring the tubing string within the wellbore at a desired location and to limit movement of the tubing string. Downhole tools can also be used to stimulate and capture production of petroleum fluids. The tubing string is also the primary conduit for conducting the petroleum fluids to the surface. 
         [0004]    Known tubing anchors use either a combination of right and left hand threads, or are limited to one thread orientation. Examples of such tubing anchors are shown in U.S. Pat. No. 3,077,933 to Bigelow and in Canadian patent no. 933,089 to Conrad. Disadvantages of such tubing anchors include the expense of manufacturing the threaded portions, the threads may be susceptible to corrosion and the threads may be difficult to, or unable to, unset if they become filled with sand or corroded. With the new technology of fracing, the industry has adopted a heavier weight casing to be able to handle the bends and ‘S’ curves that are drilled today. A heavier weight casing wall makes the interior diameter of the casing smaller. This change in diameter, combined with the wells drilled with deviations and horizontal applications, makes the setting of the older design (multiple revolutions) tubing anchor catchers and packers hard to set as it is hard to feel, or detect, at surface when the tools is set due to the friction on the side walls and having to workout the tubing twist going around bends in the well bore. 
         [0005]    Another type of tubing anchor shown in U.S. Pat. No. 5,771,969 and corresponding Canadian patent no. 2,160,647 to Garay avoids the aforementioned threads and instead uses a helical bearing to transform rotational movement into linear movement for setting and unsetting the tubing anchor. The helical bearing also accommodates shear pins for secondary unsetting if required. The use of one component, namely the helical bearing, to perform several functions has the advantage over the previous prior art of being less expensive to manufacture and less susceptible to seizing. 
       SUMMARY OF THE PRESENT INVENTION 
       [0006]    The present invention provides a tubing anchor catcher that acts to reduce or stop movement of a tubing string within a wellbore. The tubing anchor catcher may also catch the tubing string and hold the tubing string in place if a part of the tubing string disconnects or fails above tubing anchor catcher. 
         [0007]    One example embodiment of the present invention provides a tubing anchor catcher tool that is positionable within a well conduit for preventing movement of a tubing string. The tool comprises: a mandrel that is connectible at either end to the tubing string, the mandrel comprising a groove; a first cone element that is slidably mountable on to the mandrel, the first cone element comprising a first conical surface; a drag body that is slidably mountable on the mandrel, the drag body comprising a drag member that is sized for frictionally engaging an inner surface of the well conduit, a pin for engaging the groove, and a second conical surface; a biasing member that is slidably mountable on the mandrel adjacent the drag body for engaging the first cone element when the biasing member is compressed; and a slip cage that is slidably mountable on the mandrel, the slip cage comprising a slip that is adapted for engaging the inner surface of the well conduit when the mandrel is rotated a quarter turn relative to the drag body and the conical surface is disposed underneath the slip. Wherein when the second cone element is engaged, the second cone element is slidably moveable underneath the slip. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0008]    Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: 
           [0009]      FIG. 1  is an elevation side view of an example embodiment of a tubing anchor catcher; 
           [0010]      FIG. 2  is a mid-line cross-sectional view taken along line  2 - 2  in  FIG. 1 ; 
           [0011]      FIG. 3  is a mid-line cross-sectional view of  FIG. 1  showing the tubing anchor catcher with its slips extended; 
           [0012]      FIG. 4  is a perspective view of an example embodiment of a mandrel for use as part of the tubing anchor catcher of  FIG. 1 ; 
           [0013]      FIG. 5  is an enlarged view of an example embodiment of a groove that forms part of the mandrel of  FIG. 4 , showing a pin from the tubing anchor catcher engaged in the groove, in a run-in position; 
           [0014]      FIG. 6  is the view of  FIG. 5  showing the pin in a set position; 
           [0015]      FIG. 7  is a mid-line cross-sectional view of an example embodiment of a tubing anchor catcher, in the run-in position; 
           [0016]      FIG. 8  is a mid-line cross-sectional view of the tubing anchor catcher of  FIG. 7 , in the set position; 
           [0017]      FIG. 9  is a side elevation view of an example embodiment of a tubing anchor catcher; 
           [0018]      FIG. 10  is a mid-line, sectional view of the tubing anchor catcher of  FIG. 9 ; and, 
           [0019]      FIG. 11  is an exploded isometric view of the tubing anchor catcher of  FIG. 9 . 
           [0020]      FIG. 12  is an enlarged view of a portion of  FIG. 12 . 
           [0021]      FIG. 13  is a side elevation view of an example embodiment of a tubing anchor catcher positioned within a well bore. 
           [0022]      FIG. 14  is a cross-sectional view taken along line  14 - 14  in  FIG. 13 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0023]      FIGS. 1 to 8  depict one example embodiment of a tubing anchor catcher  10 . The tubing anchor catcher  10  may be inserted within a well conduit  12  (see  FIGS. 13 and 14 ), such as a wellbore casing.  FIGS. 1 and 2  depict the tubing anchor catcher  10  in an unset, or “run-in”, orientation in which it can be run inside the well conduit  12  on a tubing string. Safety subs  14 A, B may be attached to a mandrel  20  of the tubing anchor catcher  10  having attachment means, such as an inner threaded lower end  22  and an outer threaded upper end  24 . In this embodiment, the tubing anchor catcher  10  may be run down the well conduit  12  while being threadedly connected within the tubing string in the downhole direction indicated by arrow  16 . Arrow  17  indicates the opposite direction within the well conduit  12 , namely the up-hole direction. It is noted, however, that terms such as “up”, “down”, “forward”, “backward” and the like are used to identify certain features of the tubing anchor catcher  10  when placed in a well conduit. These terms are not intended to limit the tubing anchor catcher&#39;s use or orientation. Further, when describing the invention, all terms not defined herein have their common art-recognized meaning. 
         [0024]    The tubing anchor catcher  10  has an upper end  10 A and a lower end  10 B. The tubing anchor catcher  10  may comprise of a drag body  40 , a slip cage  60  and a biasing member  94 , all of which are mounted about the external surface of the mandrel  20 . The drag body  40  houses a drag means, in the form of one or more drag blocks  42 , for spacing the tubing anchor catcher  10  away from the inner wall  13  of the conduit  12 . The drag blocks  42 , for example three or four drag blocks  42 , may be generally evenly spaced circumferentially about the tubing anchor catcher  10 . Each drag block  42  has a drag spring to urge the outer surface  46  of the drag block against the well conduit&#39;s inner wall. Upper and lower drag retaining rings  48 ,  50  keep the drag blocks  42  removably mounted within the drag body  40 . In addition to keeping the tubing anchor catcher  10  spaced from the well conduit  12 , the contact of the drag block surface  46  the well conduit&#39;s  12  inner wall or surface  13  causes friction that urges the drag body  40  to remain stationary while the mandrel  20  moves within the rest of the tubing anchor catcher  10 . 
         [0025]    As will be discussed further, the drag body  40  is connected to the mandrel  20  by one or more pins  88  that extends inwardly from the drag body&#39;s  40  inner surface to engage an externally facing groove  80  that is on the outer surface of the mandrel  20 . As described further below, in one example embodiment, the pins  88  are made from a shearable material. 
         [0026]    The slip cage  60 , which may also be referred to as a slip retainer, is also mounted on the mandrel  20  adjacent the drag body  40 . In particular, the slip cage  60  is mounted on the mandrel  20  above the drag body  40  (i.e. in direction  17 ). The slip cage  60  may house one or more radially, movable slips  62 . For example, three slips  62  are depicted as being evenly spaced about the slip cage  60 , although this is not intended to be limiting as the tubing anchor catcher  10  described herein may operate with one or more slips  62 . Each slip  62  has an outer surface with teeth  63  for gripping the inner wall  13  upon contact. The teeth  63  may comprise upward gripping teeth  63 B and downward gripping teeth  63 A. The slip  62  may also have an inner surface with opposed, outwardly inclined edges with an upper edge  64 A and a lower edge  64 B. A fastener in the form of a socket head cap screw  65  is fastened to the drag body  40  and is located within each of a plurality of associated elongate slots  66  that are defined by the slip cage  60  and spaced circumferentially thereabout, preferably between each slip  62 . The cap screw  65  is adapted to contact upper and lower shoulders  68 A, B at each end of the associated slots  66 , which forms a stop means to prevent the slip cage  60 , and the drag body  40 , from longitudinally separating. 
         [0027]    A cone element  70  is mounted about the mandrel  20  at an upper end of the slip cage  60 . The cone element  70  comprises an upper edge  70 A and a lower edge  70 B. The lower edge  70 B forms a first conical surface whose inclined surface wedges under the slips  62  when the tubing anchor catcher  10  is moved into a set position. Likewise, an upper edge of the drag body  40  forms a second conical surface  54  whose inclined surface also wedges under the slips  62  when the tubing anchor catcher  10  is moved into a set position. However, the first and second conical surfaces  70 B,  54  may not actively contact the slips in the unset position. A slip spring  76  urges each slip  62  radially inwardly into the slip cage  60  and away from the well conduit  12  while in the unset position ( FIG. 2 ). 
         [0028]      FIG. 3  depicts the tubing anchor catcher  10  in the set position with the slips  62  extended outwardly from the slip cage  60  for engaging the inner surface  13  of the well conduit  12 . The slips  62  are extended due to either or both of the conical surfaces  70 B,  54  moving underneath the slips  62 . For example, when the conical surface  54  moves underneath the slip  62 , the spring  94  may be compressed, from below due to the movement of the mandrel and the tension in the tubing string, and force the first conical surface  70 B underneath the slip  62 . 
         [0029]      FIG. 4  depicts the mandrel  20  as including an upper end  20 A and a lower end  20 B. As described above, the upper and lower ends  20 A, B may each comprise threaded connections for connecting the mandrel  20  to the tubing string. As shown in  FIG. 2 , the upper end  20 A comprises a box threading and the lower end  20 B comprises a pin threading. At least one groove  80  is formed on the mandrel&#39;s outer surface  26 , as best seen in  FIGS. 4 to 6 . The groove  80  is dimensioned (width, depth) to slidingly accommodate a protruding portion of the pin  88  that extends therein threaded through a hole  56  in the drag body  40 . The lower retaining ring  50  retains the drag blocks  42  within the drag body  40 . The tubing anchor catcher  10  may comprise one or more sets of grooves  80  and pins  88 . For example, the tubing anchor catcher  10  may have three sets of grooves  80  and three sets of associated pins  88  that are generally evenly radially spaced about the mandrel  20 . 
         [0030]    As depicted in  FIGS. 5 and 6 , the groove  80  may comprise a C-shape with shoulders  82  and  86  defining a first arm  80 A of the groove  80  and shoulders  84  and  92  defining a second arm  80 B of the groove  80 . The two arms  80 A, B of the groove  80  are connected by central portion  80 C that is defined by walls  86 ,  87 ,  89  and  90 . Wall  90  separates the first and second arms  80 A, B. 
         [0031]    As seen in  FIGS. 5 and 6 , which is an enlarged view of groove  80 , a portion  88   a  of the pin  88  protudes into the groove  80  and is seated against the shoulder  92  in the run-in (i.e. un-set) position with the slips  62  retracted within the sip cage  60 . To move the pin  88  to the set position at shoulder  82 , the tubing string can be manipulated at surface so as to move axially, i.e. by pulling or pushing, and rotationally, i.e. by turning, so as to similarly manipulate the mandrel  20 . The manipulation at surface may articulate the tubing anchor catcher  10  between the run-in position and a set position. Due to the drag blocks  42  frictionally engaging the inner surface  13  of the well conduit  12 , the drag body  40  and the slip cage  60  remain relatively fixed as the mandrel  20  and the rest of the tubing string, are manipulated from surface. As manderel  20  is pulled, for example about one inch, in direction  17 , the pin  88  slides relative to mandrel  20  in direction A so as to engage the shoulder  84 . Thereafter, the mandrel  20  can be lowered, for example about 6 to 7 inches, and turned, for example, a quarter turn to the left (i.e. about 90 degrees). The turning is about the longitudinal axis of the tubing string and, therefore, the tubing anchor catcher  10 . This manipulation causes the pin  88  to move from shoulder  84 , generally along walls  89 ,  87  and  86  to rest in shoulder  86  of the first arm  80 A. When the pin  88  is in shoulder  86 , the tubing anchor catcher  10  is in a pre-set position. The tubing string, and the mandrel  20  can be turned freely to the left. Pulling the tubing string and, therefore, the mandrel  20  upwards, at least about an inch, in direction  17  will cause the pin  88  to move into shoulder  82 . When the pin  88  is in shoulder  82 , at least the conical surface  54  has moved under the slips  62  and the tubing anchor catcher  10  is set with the slips  62  extending outwards from the slip cage  60  to engage the inner surface  13  of the well conduit  12 . 
         [0032]    In this embodiment, when viewed in vertical elevation with the top of mandrel  20  upwards, groove  80  is in the shape of a reverse “C”, although this is not intended to be a literal graphical description of shapes that will work, as other shapes will work other than exact C-shapes as may mirror images of the groove  80 . 
         [0033]    To release the slips  62 , the tubing string and, therefore, the mandrel  20  can be manipulated at surface. For example, the mandrel  20  can be moved relative to the rest of the tubing anchor catcher  10 , so that the pin  88  moves out of shoulder  82 . As shown in  FIG. 6 , the mandrel  20  can be pushed down so that the pin  88  moves along line F. With a quarter turn to the left the pin will move along line H and then a straight pulling up of the tubing string and mandrel  20  will cause the mandrel  20  to move so that the pin  88  ends up in shoulder  84 . When the pin  88  has moved out of the first arm  80 A of the groove  80 , the conical surface  54  moves out from under the slips  62  and the spring  76  will cause the slips  62  to retract back into the slip cage  60 . 
         [0034]    When the tubing anchor catcher  10  is in the set position and in the event of a break in the tubing string, etc, which may cause the tubing string to fall down into the well (i.e., in direction  16 ), the tension in the tubing string is lost. This causes the weight of the tubing string to bear on the upper safety sub  14 A, which will bear on the biasing member  94 . The biasing member  94  will compress, from the weight of the tubing string above, and act against the upper edge  70 A of the cone  70 . This action causes the upper teeth  64 A to more directly engage and bite into the inner surface  13  of the well conduit  12 . For example, the greater the amount of tubing string weight that compresses the spring  94 , the harder, or more directly, the upper teeth  64 A will engage the inner surface  13  of the well conduit  12 . When the downwardly gripper teeth  64 A are more directly engaged into the inner surface  13  of the well conduit  12 , the upper teeth  64 A can hold the weight of the tubing string above the tubing anchor catcher  10 , for example, until such time that the tubing string can be recovered at surface. 
         [0035]    If it is not possible to move pin  88  in the groove  80  so as to unset slips  62 , for example due to packing of sand or other materials into the groove  80 , the slips  62  may be unset by applying a sufficient upward tension on the tubing string and the mandrel  20 . In one embodiment, the upward tension is of a sufficient amplitude to shear the pins  88 , which form the primary connection between the drag body  40  and the mandrel  20 . Then the mandrel  20  may move upward (i.e. in the direction of arrow  17 ), relative to the drag body  40 , which causes the second conical surface  54  of the drag body  40  to move out from under the slips  62 . This allows the slips  62  to retract from contacting the inner surface of the well conduit. When the slips  62  are retracted, the tubing anchor catcher  10  may be pulled out of the well conduit  12 . For example, the pin  65  may engage the lower shoulder  68 B of the slot  66  so that the slip cage  60 , and the drag body  40  do not separate. Alternatively, or additionally, the lower edge of the catcher body  40  may engage the lower safety sub  14   b  as the tubing string is pulled upwards towards the surface (i.e. in direction  17 ). 
         [0036]      FIGS. 9 to 12  depict an alternative embodiment of a tubing anchor catcher  100  with an upper end  100 A and a lower end  100   b . The tubing anchor catcher  100  may comprise many of the same features as tubing anchor catcher  10 . For example, one difference between the two tubing anchor catchers  10 ,  100  is that the pin  88  of the tubing anchor catcher  10  may be sheared as a secondary release mechanism, as described above. In contrast, the tubing anchor catcher  100  may comprise a pin  188  that is not designed to shear as a secondary release mechanism. The tubing anchor catcher  100  may comprise one or more shear pins  72  that are mounted on the lower cone  41  to drag body  40 . The shear pins  72  are made of a material that will shear in response to a lower shearing force than the shear force required to shear the pin  188 . The second conical surface  54  is formed on the upper end of cone  41  (see  FIG. 12 ). Cone  41  slidably mounts about the external surface of the mandrel  20  so that conical surface  54  in combination with conical surface  70 B on cone  70  compress together along mandrel  20  to force slip  62  into the set position, as described above. The shear pins  72  provide a secondary release of slips  62  by the application of a sufficient pulling force to the tubing string so as to shear the shear pins  72 . When the shear pins  72  are sheared, the conical surface  54  can move from under the slips  62  and the slips  62  can retract away from the inner surface  13  of the well conduit  12 . 
         [0037]    The tubing anchor catchers  10 ,  100  are thus designed to anchor the tubing string from movement longitudinally along the well (in both directions, up and down the well) and from rotating. The anchoring is achieved by simple setting and release procedures that require relatively little movement of the tubing string. In this instance, setting is achieved by a small pull and left hand rotation of the mandrel  20  (via the tubing string) that is adequate for the pins  88 ,  188  to travel the short distances within the groove  80 . Further, both tubing anchor catchers  10 ,  100  can prevent a broken tubing string from falling into the well bore by the compression of the spring  94  causing the downward gripping teeth  63 A to grip the inner surface  13  of the well conduit  12 , as described above. 
         [0038]    In one optional embodiment of the present invention, the slips  62  may be configured to center either or both of the tubing anchor catchers  10 ,  100  within the well conduit  12  by radially extending from the slip cage  60  (see  FIGS. 13 and 14 ). This may provide one or more by-pass spaces  78  between the tubing anchor catchers  10 ,  100  and the inner surface  13  of the well conduit  12 , which may create high flow areas for fluids (e.g. gas) and solids (e.g. sand) to pass by the tubing anchor catchers  10 ,  100 . The by-pass spaces  78  may also allow coil tubing to extend more easily past the tubing anchor catcher  10 ,  100 . In the  FIG. 14 , which is provided by way of example only, depicts by-pass spaces  78  with 1.0 inch (25.4 mm) radial clearance that are created between the 4.5 inch (114.3 mm) OD of the slip cage  60  and the 6.5 inch (165.1 mm) ID of the well conduit  12 . 
         [0039]    This optional embodiment of the tubing anchor catchers  10 ,  100  may permit capillary cable to be carried downhole via the large by-pass spaces  78 . In particular, the fact that the tubing anchor catchers  10 ,  100  is set and unset by longitudinal motion and a limited, quarter turn, permits its use with the capillary cable since the tubing anchor catchers  10 ,  100  may avoid wrapping of the cable around the tubing anchor catchers  10 ,  100 . In contrast, prior art anchors that require multiple full (360 degree) rotations—between two to nine full rotations for setting and unsetting—cause an undesirable wrapping of the cable around the anchor, which can damage the cable. Alternately, the cables must be pre-wrapped when inserted with these prior art anchors, so that they unwrap as the anchor is twisted during setting, which is tedious and undesirable. 
         [0040]    Optionally, the drag blocks  42  may be hardened, in comparison to prior art drag blocks, for a longer operational life. The slips  62  may optionally be made of solid high strength metal for superior durability and grip on the well conduit wall  13 , and Inconel™ type springs  76  are employed for improved resistance to H 2 S and CO 2 . Further, the surface of the mandrel  20  may optionally be coated with Teflon® for improved resistance to H 2 S and CO 2 , and to help maintain mandrel strength. 
         [0041]    While the above disclosure describes certain examples of the present invention, various modifications to the described examples will also be apparent to those skilled in the art. The scope of the claims should not be limited by the examples provided above; rather, the scope of the claims should be given the broadest interpretation that is consistent with the disclosure as a whole.