Abstract:
A tubing anchor for anchoring and catching well equipment in a well conduit to arrest movement in both longitudinal directions and rotation in a first direction. A mandrel connected to the equipment has in one embodiment C or reverse C-shaped grooves when viewed in front elevation for slideably receiving respective pins from a drag body on the mandrel. A slip retainer on the mandrel houses slips for selectively engaging and disengaging the conduit. An initial pull of the mandrel causes the pins to move the drag body toward the slip retainer driving the slips outward to grip the conduit. Rotation of the mandrel in the first direction sets the anchor to arrest movement. Further pulling and a reversed turn of the mandrel maintains the set position. A spring biases the slips outward to maintain their set to catch the well equipment in the event of a break in the string above the anchor.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from Canadian Patent Application No. ______ filed Jun. 14, 2014 entitled Quarter Turn Torque Anchor and Catcher. This application is a continuation in-part of U.S. patent application Ser. No. 13/716,075 filed ______ and entitled Quarter Turn Tension Torque Anchor. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to tools for oil and gas wells generally, including wells accessing heavy crude, and in particular relates to a ¼ turn tension torque or tubing anchor (collectively herein a tubing anchor) and catcher for anchoring from rotation and linear movement, and catching well equipment, such as a progressive cavity or rod pump, and related tubing string in a well conduit. 
       BACKGROUND OF THE INVENTION 
       [0003]    Known tubing anchors, also referred to as anchor catchers, use either a combination of right and left hand threads, or are limited to one thread orientation. 
         [0004]    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, and the stop pins are vulnerable to breakage during use. 
         [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 breakage. 
         [0006]    However, there is a need for a tubing anchor that further improves on these prior designs. In particular, there is a need for a tubing anchor that avoids the prior art threads and helical bearings that require one or more full (i.e. 360 degree) rotations of the tubing anchor&#39;s mandrel to either set or unset the tubing anchor. The tubing anchor should not need to translate rotational movement into linear movement to engage the anchor slips with the well conduit, but rather should directly transfer a short longitudinal movement of the mandrel to extend the slips into gripping engagement with the well conduit. The tubing anchor should require only a limited rotation, such as a quarter turn, of the mandrel in a first direction to set the tubing anchor, and to help maintain the anchor in the set position by merely pulling tension on the mandrel via the tubing string. One or more tracks in the mandrel, each formed by a groove having joined longitudinal and transverse arms, should guide a corresponding drive pin to achieve the desired longitudinal and rotational movements. The groove&#39;s arms should be relatively short to reduce both manufacturing costs and the risk of debris entering the groove to interfere with proper operation. The tubing anchor should have a secondary unsetting capability where release is achieved by merely pulling the mandrel at a predetermined force to sever certain fasteners mounted to the mandrel. 
       SUMMARY OF THE PRESENT INVENTION 
       [0007]    A tubing anchor for anchoring well equipment in a well conduit to arrest movement in both longitudinal directions and rotation in a first direction includes:
       a mandrel connected to said well equipment;   a first cone element slidably mounted to said mandrel and having a first conical surface;   a drag body slidably mounted on said mandrel, housing a drag or a drag means for contacting said well conduit, and having a second cone element having a second conical surface;   a slip retainer mounted on said mandrel housing at least one slip, each slip having an inner surface, and an opposed outer surface for gripping said well conduit, and a biasing device or biasing means for urging said slip inwardly toward said mandrel and away from said well conduit;   at least one pin connected to said drag body and a portion of said pin protruding toward said mandrel; and,   said mandrel having at least one groove for slideably receiving said protruding portion of said pin in sliding relation on a corresponding groove;
 
and wherein said groove has at least one longitudinally extending portion and at least one lateraly extending portion contiguous with and extending laterally of said at least one longitudinally extending portion, wherein said at least one longitudinally extending portion extends along said mandrel and said at least one laterally extending portion extends at least partially around said mandrel,
   wherein said pulling of said mandrel translates said pin to an end of said at least one longitudinally extending portion of said groove so as to said cause said pin, and in turn said second conical surface of said drag body, to move toward said first cone element,
 
and further comprising at least one spring configured to resiliently urge said first cone element towards said second conical surface to thereby provide a catcher, wherein a release of said tension caused by a break in said well equipment drives said spring, and thereby said first cone element, so as to engage said inner surface of each said slip and to said drive each said slip outward to said grip the well conduit.
       
 
         [0015]    In the preferred embodiment the at least one longitudinally extending portion includes laterally spaced apart first and second longitudinally extending portions, and the at least one laterally extending portion includes longitudinally spaced apart first and second laterally extending portions interleaved with said first and second longitudinally extending portions, so as to provide a sequence in said groove of said first longitudinally extending portion, said first laterally extending portion, said second longitudinally extending portion, and said second laterally extending portion. Also in the preferred embodiment, the first and second laterally extending portions of said groove require, for said portion of said pin to follow along said groove, that said mandrel be turned in reverse first and second corresponding directions about said axis of rotation. By way of example, said at least one laterally extending portion extends at least substantially a quarter of a circumferential distance around said mandrel; that is, substantially a quarter turn of the mandrel. 
         [0016]    When said mandrel is viewed in vertical elevation, the groove is shaped as substantially a C-shape or a reversed C-shape depending on the vertical orientation of the mandrel when so viewed, and direction of turn of the pump in the string. Thus, if the pump in the string turns to the left, when viewed from above, the mandrel is turned clockwise to the right, then left to move the pin along the groove. Unset or release is then a right turn of the mandrel. If the pump turns to the right, the mandrel is turned left then right, that is, in mirror image, and the release is a turn to the left. 
         [0017]    In embodiments with a plurality of drive pins, a corresponding a plurality of said grooves are radially spaced around the circumference of said mandrel 
         [0018]    In one embodiment the, at least one pin is a drive pin adapted to shear off to provide a secondary release when said mandrel is pulled in tension in excess of a failure shear resistance of said at least one pin. In other embodiments, separate shear pins are provided as a secondary release. 
         [0019]    In a method of anchoring well equipment in a well conduit to arrest movement in both longitudinal directions and rotation in a first direction, and to allow rotation in an opposite second direction, using a tubing anchor and catcher having:
       a mandrel connected to said well equipment, said mandrel having a longitudinal axis of rotation;   a first cone element slidably mounted on said mandrel, said first cone element having a first conical surface;   a drag body slidably mounted on said mandrel, a drag coupled to said drag body and sized to drag against said well conduit, said drag body having a second cone element having a second conical surface;   a slip retainer mounted on said mandrel, said slip retainer housing at least one slip, each slip having an inner surface, and an opposed outer surface for gripping said well conduit, and a biasing device urging each slip inwardly toward said mandrel and away from said well conduit;   at least one pin connected to said drag body and having a portion of said pin protruding toward said mandrel; and,   said mandrel having at least one groove slideably receiving said protruding portion of said pin in sliding relation in said groove;   wherein a tension applied to said well equipment causes an initial pulling on said mandrel which causes said pin, and in turn said second cone element to move toward said first cone element so that said second conical surface of said drag body contacts said inner surface of each said slips and urges said inner surface of each said slip to contact said first conical surface of said first cone element so that said first and second conical surfaces drive each said slip outward so that said outer surfaces of each said slip grips said well conduit,
 
and wherein said groove has at least one longitudinally extending portion and at least one lateraly extending portion contiguous with and extending laterally of said at least one longitudinally extending portion, wherein said at least one longitudinally extending portion extends along said mandrel and said at least one laterally extending portion extends at least partially around said mandrel,
   wherein said pulling of said mandrel translates said pin to an end of said at least one longitudinally extending portion of said groove so as to said cause said pin, and in turn said second conical surface of said drag body, to move toward said first cone element,   and further comprising at least one spring configured to resiliently urge said first cone element towards said second conical surface to thereby provide a catcher, wherein, a release of said tension caused by a break in said well equipment drives said spring, and thereby said first cone element, so as to engage said inner surface of each said slip and drive each said slip outward to said grip said well conduit,
 
wherein said at least one longitudinally extending portion includes laterally spaced apart first and second longitudinally extending portions, and wherein said at least one laterally extending portion includes longitudinally spaced apart first and second laterally extending portions interleaved with said first and second longitudinally extending portions, so as to provide a sequence in said groove of said first longitudinally extending portion, said first laterally extending portion, said second longitudinally extending portion, and said second laterally extending portion,
 
wherein said first and second laterally extending portions of said groove require, for said portion of said pin to follow along said groove, that said mandrel be turned in reverse first and second reverse directions about said axis of rotation,
 
wherein said method comprises:
   exerting an initial pull on said mandrel to move said pin along said longitudinally extending portion of said groove to extend said slips to grip said well conduit; and,   then rotating said mandrel in said first direction to move said pin along said first laterally extending portion of said groove to set said tubing anchor, then exerting a further pull on the mandrel followed by a reverse turn of said mandrel, after said rotation, so as to move said pin along said second longitudinally extending portion and said second laterally extend portion respectively to maintain said tubing anchor in said set position.       
 
         [0031]    The unsetting of said tubing anchor comprises reversing the steps to extend said slips and set said anchor. A secondary unsetting of said tubing anchor comprises increasing said further pull on said mandrel until the failure shear resistance of said pins is exceeded. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0032]    Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: 
           [0033]      FIG. 1  is a side view of a tubing anchor according to a preferred embodiment of the present invention, shown in a run (unset) orientation; 
           [0034]      FIG. 2  is a perspective view, in isolation, of a mandrel of the tubing anchor of  FIG. 1   
           [0035]      FIG. 3  shows the tubing anchor of  FIG. 1  in a run position within a segment of well conduit shown in transparent view; 
           [0036]      FIG. 3   a  is a cross-sectional view of the tubing anchor and well conduit along line  3   a - 3   a  of  FIG. 3 ; 
           [0037]      FIG. 4  shows the tubing anchor and well conduit of FIG  3  with a partially transparent view of a drag body housing; 
           [0038]      FIG. 4   a  is a close up view of the circle area  4   a  of  FIG. 4 ; 
           [0039]      FIG. 5  is a longitudinal section through the tubing anchor and well conduit of  FIG. 3 , generally along the line  5 - 5 ; 
           [0040]      FIG. 6  shows a set position of the tubing anchor of FIG  3  in the conduit; 
           [0041]      FIG. 6   a  is a cross-sectional view of the tubing anchor and well conduit along line  6   a - 6   a  of  FIG. 6 ; 
           [0042]      FIG. 6   b  is a cross-sectional view of the tubing anchor and well conduit along line  6   b - 6   b  of  FIG. 6 ; 
           [0043]      FIG. 7  is a longitudinal section through the tubing anchor and well conduit of  FIG. 6 , generally along the line  7 - 7 ; 
           [0044]      FIG. 8  is an elevation view of the tubing anchor in a further embodiment providing a catcher and improved mandrel grooves, showing a slim-hole embodiment in it&#39;s run-in position with the slips retracted; 
           [0045]      FIG. 8   a  is, in cross-section, the tubing anchor and catcher of  FIG. 8 ; 
           [0046]      FIG. 8   b  is the sectional view of  FIG. 8   a  showing the anchor in its set position with the slips extended; 
           [0047]      FIG. 9  is, in perspective view, the mandrel of  FIG. 8  showing the improved mandrel grooves spaced around the mandrel; 
           [0048]      FIG. 9   a  is an enlarged view of the mandrel grooves of  FIG. 9 , showing a pin from the drag body engaged in one of the grooves, in the run-in position; 
           [0049]      FIG. 9   b  is the view of  FIG. 9   a  showing the pin in the anchor set and locked position; 
           [0050]      FIGS. 10   a  and  10   b  are section views of a heavy crude embodiment of the tubing anchor and catcher of  FIG. 8 , in the run-in and anchor set positions respectively; 
           [0051]      FIG. 11  is an elevation view of the tubing anchor and catcher in a further embodiment proving shear pins between the slip retainer and drag blocks; 
           [0052]      FIG. 11   a  is sectional view along the lines  11   a - 11   a  in  FIG. 11 ; and, 
           [0053]      FIG. 12  is, an exploded view, the tubing anchor and catchor of  FIG. 11 . 
           [0054]      FIG. 12   a  is an enlarged view of a portion of  FIG. 12 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0055]    Referring first to  FIGS. 1 to 5 , a preferred embodiment of a tubing anchor, generally indicated by reference numeral  10 , is shown inserted within a well conduit  12 , such as a wellbore casing. The tubing anchor is shown in an unset, or “run-in”, orientation in which it can be run inside the well conduit on a tubing string, along with other well equipment  14 , such as a safety sub, attached above and below. In particular, the well equipment is attached to a cylindrical mandrel  20  having attachment means, such as an inner threaded lower end  22  and an outer threaded upper end  24 . In this embodiment, the tubing anchor is run down the well conduit on the tubing string in the direction indicated by arrow  16 . It is noted, however, that terms such as “up”, “down”, “forward”, “backward” and the like used to identify certain features of the tubing anchor when placed in a well conduit is not intended to limit the tubing anchor&#39;s use or orientation. Further, when describing the invention, all terms not defined herein have their common art-recognized meaning. 
         [0056]    The tubing anchor has a tubular drag body  40  mounted over the mandrel  20  to house a drag means in the form of multiple drag blocks  42  for spacing the tubing anchor away from the inner wall  13  of the conduit  12 . In the preferred embodiment drag blocks  42 , for example, three or four drag blocks  42 , are generally evenly spaced circumferentially about the tubing anchor. Each drag block  42  has a drag spring  44  to urge the outer surface  46  of the drag block against the conduit&#39;s inner wall  13 . Upper and lower drag retaining rings  48 ,  50  keep the drag blocks  42  removably mounted within the drag body  40 . At least one lower cap screw  52  attaches the lower retaining ring  50  to the drag body  40 . For illustrative purposes,  FIG. 3   a  shows the use of three circumferentially staggered cap screws  52 . In addition to keeping the tubing anchor spaced from the conduit, the contact of the drag block surface  46  with the conduit&#39;s inner wall  13  causes friction that urges the drag body  40  to remain stationary while the mandrel  20  moves within. 
         [0057]    A tubular slip retainer  60 , or slip cage, mounted on the mandrel  20  adjacent the drag body  40  houses a plurality of radially movable slips  62 . In the drawings three slips  62  are shown generally evenly spaced about the drag body, although this is not intended to be limiting as the anchor described herein may conceivably be made to operate with only one slip  62 . Each slip has an outer surface  63  with teeth for gripping the conduit wall  13  upon contact, and an inner surface with opposed outwardly inclined edges  64 . 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 elongate slots  66  spaced circumferentially about the slip retainer, preferably between each slip. The cap screw  65  is adapted to contact the upper and lower shoulders  68   a,    68   b  at the ends of the slot, which form stop means to prevent the slip retainer  60 , and the drag body  40 , from moving off the mandrel  20 . 
         [0058]    A cone element  70  at an upper end of the slip retainer is mounted to the mandrel  20  by a plurality of circumferentially spaced fasteners in the form of shear screws  72 . Screws  72  also act as shear pins to release the tubing anchor from a set position upon exertion of sufficient tension on the well equipment, as will be discussed later. The edge of the cone  70  opposite the screws  72  forms a first conical surface  74  whose inclined surface wedges under the slips  62  when the tubing anchor is moved into a set position. Likewise, an upper edge of the drag body  40  forms a second conical surface  54  whose inclined surface concurrently wedges under the slips  62  when the tubing anchor is moved into a set position. However, the first and second conical surfaces  74 ,  54  should not actively contact the slips in the unset position, as shown in  FIG. 5 . A biaser in the form of a slip spring  76  urges each slip  62  radially inwardly into the slip retainer and away from the well conduit  12  in the unset position ( FIG. 5 ). 
         [0059]    At least one groove  80  is formed in the mandrel&#39;s outer cylindrical surface  26 , best seen in  FIG. 2 . The L-shaped groove has a first or upper arm  82  extending longitudinally with a shoulder  83  at its upper end forming a stop and an elbow  81  at its lower end. A second or lower arm  84  extends circumferentially from the elbow  81  at a generally right angle to the upper arm  82 . A terminal end  86  of the lower arm forms another stop and has opposed indents  86   a,    86   b  extending longitudinally upwardly and downwardly therefrom. The groove  80  is dimensioned (width, depth) to slidingly accommodate a protruding portion of a drive pin  88  extending therein threaded through a hole  56  in an lower part of the drag body  40  so as to slidably engage in groove  80  ( FIG. 5 ). The lower retaining ring  50  keeps the drive pin  88  within the drag body  40  and engaged within the groove  80 . In the  FIG. 3   a  embodiment, not intended to be limiting, three sets of grooves  80  and drive pins  88  are shown generally evenly radially spaced about the mandrel. 
         [0060]    The operation of the tubing anchor may now be described including  FIGS. 6 to 7  showing the tubing anchor in the set position in the well conduit  12 . In the embodiment of  FIGS. 1-7  there are generally two steps for moving the mandrel  20  in a “setting direction” to the set position, and a third step to help lock, fix or maintain that set position. The first step is to initially pull the mandrel upwardly by lifting, that is, tensioning the tubing string  14  in the direction of arrow  17 , so that each drive pin  88  travels downwardly along the first arm  82  of the respective groove to the elbow  81  ( FIG. 2 ). In this embodiment that travel is relatively short, approximately 2.5 mm (about 1.0 inch). The pull on the mandrel forces the drive pins  88  to push the drag body&#39;s second conical surface  54  toward the first conical surface  74  of the cone element  70 . As these two components converge, the conical surfaces contact the inner edges  64  of each slip  62  to drive the slips outwards, so that the slip&#39;s outer surface  63  contacts and bites into the well&#39;s inner wall  13 . As a result, the mandrel  20  and the attached well equipment are fixed such that they can not move longitudinally in the well either up or down. At this point the second step is to turn the tubing string to the right (i.e. clockwise when looking down the tubing string in the direction of arrow  16 , in this embodiment) approximately “a quarter turn” (i.e. about 90 degrees) so that each drive pin  88  travels along the lower arm  84  from the elbow  81  to the stop  86 . At this point the mandrel and tubing string should be rotationally fixed in this first, or clockwise, setting direction. And finally the third step is to maintain the tubing anchor in this set orientation by continuing to pull tension on the tubing string straight up in direction  17 , which should also engage the drive pin  88  with the lower indent  86   b  which secures the pin upon entry to aid in maintaining the set position. The drill string should be kept in tension as long as the set position is desired. This description is suited for the situation where the pump in the drill string is a rod pump. In embodiments where the pump turns to the right, for example in the case of a progressive cavity pump system, the mandrel locking movement would be reversed, that is, the mandrel is moved upwards then left and the corresponding groove shape would also be reversed, i.e., a J-shape as opposed to an L-shape, collectively referred to herein as an L-shape. 
         [0061]    The tubing anchor is released, or unset, by reversing the above described setting procedure. The first unsetting step requires release of tension by moving the tubing string, and hence the mandrel  20 , down somewhat, which should move the drive pins  88  out of the corresponding lower indents  86   b  to the upper indents  86   a  which temporarily “store” the pins on exit. The second step requires rotating the tubing string and mandrel in a second direction opposite to the setting rotation, namely turning to the left (i.e. counter-clockwise when looking down the tubing string in the direction of arrow  16 , in this embodiment) approximately “a quarter turn” so that each drive pin  88  travels from the upper indents  86   a  along the lower arm  84  to the elbow  81 . Finally, in a third step, the mandrel should be moved further down relative to the drag body so that the drive pin  88  travels up the upper arm  82  from the elbow  81  toward the stop  83 . After the pin reaches this stop, continuing this mandrel movement causes the drag body  40  to move downwards, and thereby the second conical surface  54  to move away from the inner edge  64  of each slip  62 . The springs  76  urge the respective slips  62  inwardly away from the well&#39;s inner wall  13 , thus releasing the tubing anchor for movement longitudinally (both up and down the well) and rotationally (in the unsetting direction). This allows the tubing anchor to be moved to a different position in the well conduit  12  and be set again, or to lift the tubing anchor and remove it from the well conduit. 
         [0062]    An alternate method of unsetting the tubing anchor is to pull tension on the tubing string to exert sufficient upward force on the mandrel  20  to shear the shear screws  72  by exceeding their maximum shear resistance. Once the shear screws  72  are sheared, the cone element  80  becomes detached from the mandrel  20  and is free to move away, namely upward, from the slips  62 , allowing the springs  76  to retract the slips away from the inner surface  13  of the conduit. The torque anchor is therefore freed for removal from the well conduit  12 . The maximum shear resistance may be “adjusted” by either changing the shear screws  72  to ones with a different shear value, or by altering the number of shear screws inserted into the cone element  80 . For instance, in one version of the tubing anchor, twelve brass screws  72  can be employed each with about 5000 pounds (2273 kg) resistance, and their maximum shear resistance does not exceed that of the drive pins  88  to avoid damaging the pins during such secondary release of the tubing anchor. 
         [0063]    The tubing anchor  10  is thus designed to anchor the tubing string from movement longitudinally along the well (in both directions, up and down the well) and from rotation (in the setting direction). The anchoring is achieved by simple setting and release procedures with relatively little movement of the tubing string. In this instance, setting is achieved by a small pull of the mandrel (via the tubing string) that is adequate for the drive pin  88  to travel the short distance along the longitudinal arm  82  to reach the elbow  81 , and then by a small “quarter” turn of the mandrel that is adequate for the drive pin  88  to travel the short distance along the circumferential arm  82  to reach the toe  85 , and finally by further pulling to engage the drive pin  88  with the lower indent  86   b.  The tubing anchor  10  avoids the more labourious and time consuming multiple full rotations of the mandrel that are currently required to set a tubing anchor. The relatively short L-shaped groove  80 , in comparison to the multiple twists of the long threads or helical groove of other mandrels, reduces the risk of foreign objects obstructing the drive pin&#39;s travel path, and thus should improve the tubing anchor function, reliability and wear. 
         [0064]    Also, since this anchoring is achieved by placing the tubing string in tension, there is an added benefit of ensuring that the tubing follows the rod string as closely as possible, which helps minimize rod wear. 
         [0065]    Some further benefits are set out below. 
         [0066]    The configuration of the tubing anchor, including the arrangement of the set screws with a given shear resistance below that of the drive pins  88 , provides a relatively fast and easy secondary unsetting of the tubing anchor in case of an emergency or should a problem be encountered with the primary means of setting and unsetting via the L-shaped groove  80 . 
         [0067]    Referring to  FIG. 6   b , the slips  62  are configured not only to centre the tubing anchor within the well conduit  12 , but radially protrude sufficiently from the slip retainer  60  to provide large by-pass spaces  78  between the tubing anchor and the conduit, creating high flow areas for fluids (eg. gas) and solids (eg. sand) to pass by the tubing anchor, and allowing coil tubing to more easily extend past the tubing anchor, than other tubing anchors. In the  FIG. 6   b  version, for instance, by-pass spaces  78  with 1.0 inch (25.4 mm) radial clearance are created between the 4.5 inch (114.3 mm) OD of the slip retainer  60  and the 6.5 inch (165.1 mm) ID of the well conduit  12 . 
         [0068]    The configuration of the tubing anchor  10  permits capillary cable to be carried downhole via the large by-pass spaces  78  created by this novel tubing anchor design. In particular, the fact that the tubing anchor  10  is set and unset by longitudinal motion and a limited, quarter turn, permits its use with the capillary cable since the anchor stays relatively straight during use, thus avoiding wrapping of the cable around the anchor. In contrast, prior art anchors that require multiple full (360 degree) rotations—between two to seven full rotations for setting and unsetting—cause an undesireable wrapping of the cable around the anchor, which damages 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 undesireable. 
         [0069]    The drag blocks  42  have been hardened, over prior art drag blocks, for longer life. The slips  62  are 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  is optionally coated with Teflon® for improved resistance to H 2 S and CO 2 , and to help maintain mandrel strength. 
         [0070]    In the alternative embodiments of  FIGS. 8-10   b , a version of anchor tool that also serves as a catcher is illustrated. The embodiment of  FIGS. 8-10   b  also illustrates an improved groove configuration that replaces the L-shaped groove  80  of  FIG. 2 . 
         [0071]    Applicant has determined that in some circumstances improved locking of the slips  62  in their set position is desirable, for example in circumstances where the pump is causing excessive vibration sufficient to potentially un-set the slip over time when using the L-shape groove embodiment of  FIGS. 1-7 . Consequently groove  180  best seen in  FIGS. 9   a ,  9   b  provides increased security for locking pin  88  in its set position. 
         [0072]    As seen in  FIG. 9   a , which is an enlarged view of groove  180  in  FIG. 9 , the portion  88   a  of pin  88  which protrudes into groove  180 , seats against shoulder  182  in its run-in (i.e. un-set) position. As mandrel  20  is pulled in direction  17 , pin  88   a  slides relatively to mandrel  20  in direction D so as to engage in shoulder  182 . Thereafter further pulling of mandrel  20  in direction  17  pulls drag body  40  in direction  17  so as to set slips  62  from slip retainer  60 . 
         [0073]    In the embodiment of  FIGS. 1-7 , as described above, once slips  62  are set, mandrel  20  is rotated about its longitudinal axis A a one-quarter turn in direction B, i.e., in the illustrated embodiment, not intending to be limiting, right or clock-wise when looking down mandrel  20  from its top end (end  24 ), so as to lock slips  62  in the set position (i.e., extended to grip the inner surface of casing  12 ). 
         [0074]    In the embodiment of  FIGS. 8 -10   b,  and as best seen in  FIGS. 9   a  and  9   b , pin  88  is moved as follows in groove  180  so as to position portion  88   a  of pin  88  against shoulder  184 :
       a) as already described, as mandrel  20  is first pulled upwardly in direction  17 , portion  88   a  of pin  88  slides in direction D until it engages against shoulder  182 ;   b) mandrel  20  is then pulled further in direction  17  to set slips  62  outwardly of slip  60  to engage against the casing wall;   c) mandrel  20  is then given a quarter turn to the right so as to move portion  88   a  of pin  88  in direction E laterally within groove  180 , i.e. laterally around mandrel  20  in direction E, until pin  88  abuts longitudinal wall  186 ;   d) continued upward tension on mandrel  20  then slides pin  88  longitudinally along longitudinal wall  186  in direction F;   e) once pin  88  reaches corner  188  in groove  180 , mandrel  20  is rotated to the left, i.e., back a quarter turn in direction G while pulling mandrel  20  in direction  17  (i.e. in tension upwardly) so that pin  88  follows laterally along inclined wall  190  until pin  88  is stopped against shoulder  184 .       
 
         [0080]    In this embodiment, when viewed in vertical elevation with the top of mandrel  20  upwards, groove  180  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. Thus in this embodiment the mandrel  20  is turned, while in tension, first right and then left, and requires a right turn to release or unset the slips. In embodiments for pumps which turn the right, for example in progressive cavity pump systems. groove  180  would be for example “C” shaped so that mandrel  20  is turned under tension first left then right, requiring a left turn to release the slips. This embodiment is not illustrated as it is a mirror image of the illustrated embodiment. 
         [0081]    Shoulder  184  forms a pocket in which portion  88   a  of pin  88  sits while mandrel  20  remains under tension in direction  17 . Because the pocket formed by shoulder  184  is at the bottom, that is, the lower end, of groove  180 , pin  88  and thus drag body  40  cannot move relative to mandrel  20  while mandrel  20  remains in tension in direction  17 . Slips  62  thus remain locked in their set position so long as mandrel  20  remains in tension in direction  17 . Movement of drag body  40  relative to mandrel  20  is prevented, and vibration of mandrel  20  cannot move pin  88  so as to unintentionally allow slips  62  to un-set. 
         [0082]    In the event of a break in the tubing string, etc, which allows the tubing string to fall down into the well (i.e., in direction  16 ), pin  88  slides in direction H until it is stopped and held within pocket  192 . As drag body  40  is thereby also urged in direction  16 , which would unset slips  62  where it not for the catcher function, instead, spring  194  maintains cone  70  in its position wedged under slips  62 , thereby maintaining slips  62  in their set position, even as conical surface  54  is slightly pulled away from under slips  62 . Spring  194  thus slides slip receiver  60  and slips  62  so as to maintain conical surface  54  on drag body  40  firmly wedged under slips  62 , along with cone  70 . The slips are thus maintained in their set position preventing the tubing string from sliding further down into the casing. 
         [0083]    Until the break is repaired, pin  88  remains locked in pocket  192  in groove  180 , preventing any turning movement of mandrel  20  relative to the drag body  40 . Once the break is repaired and the catcher function is no longer required, upward tension may then be re-applied to mandrel  20  in direction  17  to thereby again slide portion  88   a  of pin  88  down into shoulder  184  and lock slips  62  in their continued set position. 
         [0084]    When it is desired to unset slips  62 , the process of setting the slips is reversed, so that portion  88   a  of pin  88  is returned from shoulder  184  to run-in position  186 . To accomplish this, mandrel  20  is quarter-turned right or clockwise while lowering mandrel  20 , then quarter-turned left or counter-clockwise (again from the perspective of looking down mandrel  20  from its upper end). 
         [0085]    As before, if it is not possible to move pin  88  in groove  180  so as to unset slips  62 , for example due to packing of sand or the like into groove  180 , the slips  62  may be unset by applying a sufficient upward tension on the mandrel. In one embodiment the shearing tension and/or torque shears off the drive pins  88 , i.e. shears off the only pins connecting drag body  40  to mandrel  20 . In alternative embodiments, shear screws or pins may be provided as per in the embodiments of  FIGS. 1-7 . In the embodiments of  FIGS. 8 -10   b , cone  70  is not screwed or pinned to mandrel  20 , but rather the shear screws or pins may mount below the drag blocks  42  on the drag body  40 . 
         [0086]    In the further embodiments of  FIGS. 11-12 , shear pins  72  mount lower cone  41  to drag body  40 . Second conical surface  54  is formed on the upper end of cone  41 . Cone  41  slidably mounts onto mandrel  20  so that conical surface  54  in combination with first conical surface  74  on cone  70  compress together along mandrel  20  to force slip  62  into their set position as described above. As before, shear pins  72  provide a secondary release of slips  62  by the application of sufficient force to the drill string so as to shear the shear pins.