Patent Abstract:
A casing spear may comprise a mandrel, and a slip assembly comprising at least one slip. The at least one slip may comprise a generally wedge-shaped surface positioned and configured to cause the at least one slip to move radially outwards relative to the mandrel in response to a rotation of the mandrel and a torque acting on the slip assembly, the torque opposing the rotation of the mandrel. Additionally, a method of operating a casing spear may comprise inserting a casing spear into a casing, rotating a mandrel of the casing spear, applying a torque to a slip assembly of the casing spear with the casing, opposing the rotation of the mandrel, and applying a force in a radial direction to at least one slip of a slip assembly of the casing spear in response to the torque.

Full Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is claims priority from U.S. Provisional Patent Application Ser. No. 61/411,195 for “Casing Spears and Related Systems and Methods, filed on Nov. 8, 2010, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the present invention relate to manipulating casing for subterranean well bores. More particularly, embodiments of the present invention relate to methods and apparatus for gripping and rotating casing by the interior thereof from the earth&#39;s surface, which methods and apparatus may be employed to drill or ream with casing. 
     BACKGROUND OF THE INVENTION 
     It is known in the art of subterranean drilling to use a so-called “top drive” to connect a section, also known as a “joint,” of well bore casing above a drilling rig floor to the upper end of a casing string substantially disposed in the well bore. Such casing strings, commonly termed “surface casing,” may be set into the well bore as much as 3,000 feet (914.4 meters), and typically about 1,500 feet (457.2 meters), from the surface. 
     Examples of methods and apparatus for making casing joint connections to a casing string are disclosed in U.S. Pat. Nos. 6,742,584 and 7,137,454, the disclosure of each of which patents is incorporated herein by this reference. 
     It is known in the art of subterranean drilling to drill and ream with casing, using a drilling or reaming shoe including a cutting structure thereon to drill a well bore, or to ream an existing well bore to a larger diameter, to remove irregularities in the well bore, or both. It would be highly desirable for the subterranean drilling industry to employ a top drive to apply weight on the casing in combination with casing rotation to drill or ream with casing using a drilling or reaming device at the distal end of the casing string. Additionally, improved casing spears for such applications would be desirable. 
     SUMMARY OF THE INVENTION 
     In one embodiment, a casing spear may comprise a mandrel, and a slip assembly comprising at least one slip. The at least one slip may comprise a generally wedge-shaped surface positioned and configured to cause the at least one slip to move radially outwards relative to the mandrel in response to a rotation of the mandrel and a torque acting on the slip assembly, the torque opposing the rotation of the mandrel. 
     In another embodiment, a method of operating a casing spear may comprise inserting a casing spear into a casing, rotating a mandrel of the casing spear, applying a torque to a slip assembly of the casing spear with the casing, opposing the rotation of the mandrel, and applying a force in a radial direction to at least one slip of a slip assembly of the casing spear in response to the torque. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an elevation of a casing spear, according to an embodiment of the present invention, in a run-in position. 
         FIG. 1B  is a cross-sectional view of the casing spear of  FIG. 1A , in the run in position. 
         FIG. 1C  is an elevation of the casing spear of  FIG. 1A  in a set position. 
         FIG. 1D  is a cross-sectional view of the casing spear of  FIG. 1A , in the set position. 
         FIG. 2  is an isometric view of a slip for a casing spear, such as shown in  FIG. 1A . 
         FIG. 3  is a schematic of a casing spear, such as shown in  FIG. 1A , disposed within a casing joint of a casing string above another casing joint. 
         FIG. 4A  is an elevation of a casing spear, according to an additional embodiment of the present invention, in a run-in position. 
         FIG. 4B  is a cross-sectional view of the casing spear of  FIG. 4A , in the run in position. 
         FIG. 4C  is an elevation of the casing spear of  FIG. 4A  in a set position. 
         FIG. 4D  is a cross-sectional view of the casing spear of  FIG. 4A , in the set position. 
         FIG. 5  is an isometric view of a slip for a casing spear, such as shown in  FIG. 4A , including carbide inserts. 
         FIG. 6  is an isometric view of a slip for a casing spear, such as shown in  FIG. 4A , including wickers. 
         FIG. 7  is an isometric view of a slip for a casing spear, such as shown in  FIG. 4A , including wickers in an additional configuration. 
         FIG. 8A  is an elevation of a casing spear, according to an additional embodiment of the present invention, in a run-in position. 
         FIG. 8B  is a cross-sectional view of the casing spear of  FIG. 8A , in the run in position. 
         FIG. 8C  is a cross-sectional detail view of the casing spear of  FIG. 8A , in a set position. 
         FIG. 9A  is an elevation of a casing spear, according to an additional embodiment of the present invention, in a run-in position. 
         FIG. 9B  is a cross-sectional view of the casing spear of  FIG. 9A , in the run in position. 
         FIG. 9C  is a cross-sectional detail view of the casing spear of  FIG. 9A , in a set position. 
         FIG. 10  is an isometric view of a slip for a casing spear, such as shown in  FIG. 9A . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The illustrations presented herein are not actual views of any particular drilling system, assembly, or device, but are merely idealized representations which are employed to describe embodiments of the present invention. 
     While embodiments of the present disclosure are described herein with respect to manipulation of, and drilling with, casing, it is also contemplated that an appropriately sized drive assembly may be used to engage, rotate, and apply weight for drilling with any suitable tubular goods having sufficient longitudinal compressive and torsional (shear) strength to withstand application of longitudinal force and torque for drilling. Accordingly, as used herein, the term “casing” means and includes not only convention casing joints but also liner joints, drill pipe joints, and drill collar joints. In addition, multiple joint assemblies, termed “stands,” of any and all of the foregoing tubular goods may be used with, and manipulated by, embodiments of the apparatus of the present disclosure and in accordance with methods of the present disclosure. 
     As used herein, the terms “upper,” “lower,” “above,” and “below,” are used for the sake of clarity in a relative sense as an embodiment of the casing drive assembly is oriented during use to manipulate and drive a casing joint or string. 
     In some embodiments, such as is shown in the preferred embodiment of  FIGS. 1A-1D , a casing spear  10  may comprise a mandrel  12 , a circumferential stop collar  14 , a slip assembly  16 , and a drag block assembly  18 . Additionally, the casing spear  10  may include a cup type packer, such as cup type packer  120  shown in  FIGS. 4A-4D . The mandrel  12  may include a longitudinal fluid passage  20  ( FIGS. 1B and 1D ) extending therethrough and include a retention ring  22  ( FIGS. 1B and 1D ) extending radially outward. The circumferential stop collar  14  may be coupled to a spacing sleeve  24  and the spacing sleeve  24  may be coupled to an upper sub  26  of the slip assembly  16 , such as by interlocking threads. The upper sub  26  and the spacing sleeve  24  may be positioned on either side of the retention ring  22  of the mandrel  12 , such that the retention ring  22  may prevent the longitudinal movement of the upper sub  26  and the spacing sleeve  24  relative to the mandrel  12 . Likewise, the spacing sleeve  24  may prevent the longitudinal movement of the circumferential stop collar  14  relative to the mandrel  12 . 
     The slip assembly  16  may include a plurality of slips  28 , the upper sub  26  and a lower sub  30 . Each of the upper sub  26  and the lower sub  30  may include slots  32  ( FIGS. 1A and 1C ) configured to receive a tail piece  34  of a corresponding slip  28 . The tail piece  34  of each slip  28  may be inserted into a slot  32  of one of the upper sub  26  and lower sub  30  and slidably coupled thereto. 
     Each slip  28  (as shown in isometric view in  FIG. 2 ) may also include interlocking features  36  to slidably couple each slip  28  to slips  28  circumferentially adjacent thereto. In view of this, each slip  28  may be slidable in a radial direction relative to the upper sub  26  and the lower sub  30 , and the slips  28  coupled to the lower sub  30  may be slidable in an axial direction relative to the slips  28  coupled to the upper sub  26 . Each slip  28  may also have a general wedge shape in the region of the interlocking features  36  wherein the slips  28  are slidably coupled to adjacent slips  28 , such that as the tail pieces  34  of the slips  28  are moved closer together, the slips  28  may be urged radially outwards. The outer surfaces  38  of the slips  28  may comprise gripping structures. Such gripping structures may comprise, by way of example, machined teeth, wickers (such as are shown in  FIGS. 6 and 7 ), crushed tungsten carbide, tungsten carbide inserts in the form of bricks, buttons or discs (such as are shown in  FIG. 5 ) inserted into pockets  40 , superabrasive elements such as natural or polycrystalline diamond, or a combination thereof. In one embodiment, such as shown in  FIG. 5 , the gripping structures comprise tungsten carbide inserts in the form of buttons having four projecting, pyramidal points. In additional embodiments, the gripping structures may be wickers, such as shown in  FIGS. 6 and 7 , which may be oriented in an axial direction, a circumferential direction, another direction or a combination thereof. 
     As shown in  FIGS. 1B and 1D , the lower sub  30  may include a threaded region  42  mated with corresponding threads on the outer surface of the mandrel  12 . Additionally, the lower sub  30  may be fixedly coupled to the drag block assembly  18 . The drag block assembly  18  may include a plurality of drag blocks  44  circumferentially distributed within a frame  46 , and the drag blocks  44  may be biased radially outward, such as by helical compression springs. 
     In use, and with reference to drawing  FIG. 3 , wherein a casing joint  50  is shown disposed above another casing joint  52 , a single joint of casing is picked up using rig elevators, as is conventional, and stabbed up into an existing casing joint (if a casing string has already been started). A casing spear  10  in a run-in position, such as shown in  FIGS. 1A and 1B , is made up with and suspended from a top drive via a slack joint, and lowered by the top drive into the bore of the casing joint  50  from the top thereof. The elevators stay latched and ride down the casing joint  50  during this operation. 
     If a casing joint is the first joint in the casing string, a cutting structure, such as a drilling or reaming device, is made up with the lower end thereof prior to insertion of casing spear  10 . Examples of such devices are, for drilling, the EZ Case™ casing bit and, for reaming, the EZ Ream™ shoe, each of which is commercially available from the assignee of the present disclosure. Otherwise, such a device  54  is already secured to the distal end of the lowermost casing joint  52  in the casing string  56 . 
     Upon insertion of the casing spear  10  into the casing joint  50 , one or more pumps associated with the drilling rig may be engaged, and circulation of drilling fluid, also known as “mud,” established through the casing drive assembly  10  through the longitudinal passage  20  of the mandrel  12  and out into the interior of the casing joint  50 . Upward circulation of drilling fluid within the casing joint  50  may be precluded by a packer cup (such as packer cup  120  shown in  FIGS. 4A-4D ), which expands against and seals with the interior of the casing joint  50  under drilling fluid pressure. 
     The casing spear  10  may then be rotated, such as in a right-hand direction (i.e., clockwise looking down into the borehole). Friction between the drag blocks  44  and an inner surface of the casing  50  may be used to apply a torque to the drag block assembly  18 . The torque acting on the drag block assembly  18  will also act on the lower sub  30 , which is coupled to the drag block assembly  18 . The torque on the lower sub  30  will cause the lower sub to rotate relative to the mandrel  12  at the threaded connection therebetween. Upon rotation, the threads will guide the lower sub  30  upwards, toward the upper sub  26 . Optionally the upper sub  26  can be driven toward or away from lower sub  30  with an opposite hand threaded connection to the mandrel  12 . 
     As the lower sub  30  is moved closer to the upper sub  26 , the slips  28  will intermesh and each slip  28  will slide axially toward the slips  28  adjacent thereto. The general wedge shape of the slips  28  will cause the slips  28  to be urged radially outwards as the lower sub  30  moves upwards, toward the upper sub  26 . When the slips  28  have been urged sufficiently radially outwards to a set position, such as shown in  FIGS. 1C and 1D , the gripping structures of the slips  28  may grip the inner surface of the casing joint  50 , and the torsion applied to the mandrel  12  may be applied to the casing through the slips. 
     The casing spear  10 , with the casing joint  50  secured thereto, is then rotated by the top drive (the top drive also being used to provide an axial force, which is commonly termed “weight”) to rotate the casing joint  50  and any others therebelow (if any) in the casing string and drilling, reaming, or another downhole operation commences. Notably, both torque and weight are applied to the casing joint  50  via engagement of the casing spear  10  substantially only with the interior of the casing joint  50 . 
     The rig elevators remain attached as the casing joint  50  descends until a point just above the rig floor. To remove the casing spear  10 , the mandrel  12  may be rotated in the opposite direction, such as in a left-hand direction (i.e., counter-clockwise looking down into the borehole), which may cause the lower sub  30  to be forced axially downward, away from the upper sub  26 . As the lower sub  30  is moved axially away from the upper sub  30 , the slips  28  may retract axially toward the mandrel  12  and returned to the run-in position, as shown in  FIGS. 1A and 1B . Then, the casing spear  10  may be removed from the casing  50  for subsequent insertion into another casing joint  50  picked up by the rig elevators, and the above-described process may then be repeated. 
     In an additional embodiment, as shown in  FIGS. 4A-4D , a casing spear  100  may comprise a mandrel  112 , a circumferential stop collar  114 , a slip assembly  116 , a drag block assembly  118  and a cup type packer  120 . The mandrel may include a longitudinal fluid passage  122  ( FIGS. 4B and 4D ) extending therethrough and may be coupled to an assembly that includes the loosely mounted cup type packer  120 , such as by a threaded connection. Additionally, the circumferential stop collar  114  may be coupled to the mandrel  112  such that the stop collar  114  may be prevented from axial movement relative to the mandrel  112 . 
     The slip assembly  116  may include a plurality of slips  124 , an outer housing  126 , an upper wedge  128  and a lower wedge  130  ( FIGS. 4B and 4D ). The outer housing  126  may be rotatably coupled to the mandrel  112  and each of the slips  124  may be positioned within the outer housing  126  and portions of the slips  124  may extend through apertures in the outer housing  126 . The upper wedge  128  and the lower wedge  130  may be positioned radially between the mandrel  112  and the outer housing  126 . The upper wedge  128  may be positioned axially above the slips  124  and the lower wedge  130  may be positioned axially below the slips  124 . The slips  124  may include surfaces that are angled (e.g., at an acute angle) relative to a longitudinal axis of the mandrel  112  and the upper and lower wedges  128  and  130  may include angled surfaces adjacent respective angled surfaces of the slips  124  and oriented at a supplemental angle thereto. The outer surfaces  132  of the slips comprise gripping structures. Such gripping structures may comprise, by way of non-limiting example, machined teeth, wickers, crushed tungsten carbide, tungsten carbide inserts  134  in the form of bricks, buttons or discs, superabrasive elements such as natural or polycrystalline diamond, or a combination thereof. In one embodiment, such as shown in  FIG. 5 , the gripping structures comprise tungsten carbide inserts  134  in the form of buttons having four projecting, pyramidal points. In additional embodiments, the gripping structures may be wickers  135 ,  137 , such as shown in  FIGS. 6 and 7 , which may be oriented in an axial direction ( FIG. 6 ), a circumferential direction, another direction or a combination thereof ( FIG. 7 ). 
     A linear slide  136  ( FIGS. 4A and 4C ) may prevent or limit circumferential movement of the outer housing  126  relative to each of the upper wedge  128  and the lower wedge  130 . The linear slide  136  may allow relative linear motion between the outer housing  126  and each of the upper wedge  128  and the lower wedge  130  in an axial direction. For example, the outer housing  126  may include slots positioned over each of the upper wedge  128  and the lower wedge  130 , and corresponding pins (e.g., cap screws) may extend into the slots, respectively. The pins may be coupled to the upper wedge  128  and the lower wedge  130 , respectively, and limit the respective range of motion of the upper wedge  128  and the lower wedge  130 . 
     Each of the upper wedge  128  and the lower wedge  130  may include a threaded region  138  mated with corresponding threads on the outer surface of the mandrel  112 . Additionally, the outer housing  126  may be fixedly coupled to the drag block assembly  118 . The drag block assembly  118  may include a plurality of drag blocks  140  circumferentially distributed within a frame  142 , and the drag blocks  140  may be biased radially outward, such as by helical compression springs. 
     In a run-in position, such as shown in  FIGS. 4A and 4B , the casing spear  100  may be inserted into a casing joint  50 , which may be made up with another casing joint  52  already positioned in a well bore similarly as to described with reference to  FIG. 3 , and the casing spear  100  may be rotated, such as in a right-hand direction (i.e., clockwise looking down into the borehole). Friction between the drag blocks  140  and an interior surface of the casing may be used to apply torque to the drag block assembly  118 . The torque acting on the drag block assembly  118  will also act on outer housing  126 , which is coupled to the drag block assembly  118 , as well as the slips  124 , the upper wedge  128  and the lower wedge  130 . The torque on the upper wedge  128  and the lower wedge  138  will cause the upper wedge  128  and the lower wedge  130  to rotate relative to the mandrel  112  at the threaded connections therebetween. Upon rotation, the threads will guide the upper wedge  128  downward, toward the lower wedge  130 , and will guide the lower wedge  130  upwards, toward the upper wedge  128 . 
     As the upper wedge  128  and the lower wedge  130  are urged together, the angled surfaces of the upper wedge  128  and the lower wedge  130  will be forced against the angled surfaces of the slips  124 . The general wedge-like shapes of the slips  124  and upper and lower wedges  128  and  130  will cause the slips  124  to be urged radially outwards through the apertures in the outer housing  126  as the upper wedge  128  and the lower wedge  130  are urged together. When the slips  124  have been urged sufficiently radially outwards to a set position, such as shown in  FIGS. 4C and 4D , the gripping structures of the slips  124  may grip the inner surface of the casing, and the torsion applied to the mandrel  112  may be applied to the casing through the slips  124 . Additionally, upon the slips  124  contacting the inner surface of the casing, the torsion applied to the slips  124  may cause the slip assembly  116  to rotate relative to the mandrel  112 , or at least provide torsion between the slip assembly  116  and the mandrel  112 , which will provide additional force to urge the upper and lower wedges  128  and  130  together as the mandrel  112  is rotated. In view of this, as the torque applied to the slips  124  is increased, the axial force applied by the slips  124  to the inner surface of the casing may be increased. 
     To remove the casing spear  100 , the mandrel  112  may be rotated in the opposite direction, such as in a left-hand direction (i.e., counter-clockwise looking down into the borehole), which may cause the lower wedge  130  to be forced downward, away from the upper wedge  128 . As the lower wedge  130  is moved longitudinally away from the upper wedge  128 , the slips  124  may retract axially toward the mandrel  112  and the casing spear  100  may be removed from the casing. 
     In additional embodiments, the upper wedge  128  may be fixed relative to the mandrel  112  and the lower wedge  130  and the slips  124  may be urged toward the upper wedge  128  upon rotation of the mandrel  112  and the lower wedge  130  and the slips  124  may be urged away from the upper wedge  128  upon reverse rotation of the mandrel  112 . In yet further embodiments, the lower wedge  130  may be fixed relative to the mandrel  112  and the upper wedge  128  and the slips  124  may be urged toward the lower wedge  130  upon rotation of the mandrel  112  and the upper wedge  128  and the slips  124  may be urged away from the lower wedge  130  upon reverse rotation of the mandrel  112 . 
     In an additional embodiment, such as shown in  FIGS. 8A-8C , a casing spear  200  may comprise a mandrel  212 , a circumferential stop collar  214 , a slip assembly  216 , and a cup type packer  218 . The mandrel  212  may include a longitudinal fluid passage  220  ( FIGS. 8B and 8C ) extending therethrough and the mandrel  212  may be coupled to the cup type packer  218 , as shown. Optionally, the mandrel  212  may be coupled to an assembly that includes a cup type packer, such as by a threaded connection, as shown in  FIG. 3 . Additionally the circumferential stop collar  214  may be coupled to the mandrel  212  such that the stop collar  214  may be prevented from axial movement relative to the mandrel  212 . 
     The slip assembly  216  may include a plurality of slips  222 , an outer housing  224 , an upper wedge  226 , a lower wedge  228  ( FIGS. 8B and 8C ), and a lock ring  230 . The outer housing  224  may be rotatably coupled to the mandrel  212  and each of the slips  222  may be positioned within the outer housing  224  and portions of the slips  222  may extend through apertures in the outer housing  224 . The upper wedge  226  and the lower wedge  228  may be positioned radially between the mandrel  212  and the outer housing  224 . The upper wedge  226  may be positioned axially above the slips  222  and the lower wedge  228  may be positioned axially below the slips  222 . The slips  222  may include surfaces that are angled relative to the longitudinal axis of the mandrel  212  and the upper and lower wedges  226  and  228  may include angled surfaces adjacent respective angled surfaces of the slips  222  and oriented at a supplemental angle thereto. The outer surfaces of the slips  222  may comprise gripping structures. Such gripping structures may comprise, by way of non-limiting example, machined teeth, wickers, crushed tungsten carbide, tungsten carbide inserts in the form of bricks, buttons or discs, superabrasive elements such as natural or polycrystalline diamond, or a combination thereof. In one embodiment, such as shown in  FIG. 5 , the gripping structures comprise tungsten carbide inserts in the form of buttons having four projecting, pyramidal points. In additional embodiments, the gripping structures may be wickers, such as shown in  FIGS. 6 and 7 , which may be oriented in an axial direction, a circumferential direction, another direction or a combination thereof. 
     A helical compression spring  232  ( FIGS. 8B and 8C ) may be positioned between the upper wedge  226  and the lower wedge  228 , and the lock ring  230  may be positioned below the lower wedge  228 . The lock ring  230  may include a threaded region  234  mated with corresponding threads on the outer surface of the mandrel  212 . One or more fluid paths  236  may provide fluid communication between the longitudinal fluid passage  220  of the mandrel  212  and a fluid space  238  between the lock ring  230  and the lower wedge  228 . 
     In a run-in position, such as shown in  FIGS. 8A and 8B , the casing spear  200  may be inserted into a casing joint  50 , which may be made up with another casing joint  52  positioned in a well bore similarly as to described with reference to  FIG. 3 . Via the longitudinal passage  220  of the mandrel  212  drilling fluid may be directed through the one or more fluid paths  236  into the fluid space  238  between the lock ring  230  and the lower wedge  228 , which may cause the lower wedge  228  to be pushed longitudinally upward, toward the slips  222  and the upper wedge  226 . 
     As the lower wedge  228  is urged upward, toward the upper wedge  226 , the angled surfaces of the upper wedge  226  and the lower wedge  228  will be forced against the angled surfaces of the slips  222 . The general wedge-shapes of the slips  222  and upper and lower wedges  226  and  228  will cause the slips  222  to be urged radially outwards as the lower wedge  228  moves upwards, toward the upper wedge  226 . When the slips  222  have been urged sufficiently radially outwards to a set position, as shown in  FIG. 8C , the gripping structures of the slips  222  may grip the inner surface of the casing, and the rotational force applied to the mandrel  212  may be applied to the casing through the slips  222 . 
     Initially, the slip assembly  216  may rotate relative to the mandrel  212  as the slips  222  grip the inner surface of the casing and the mandrel  212  is rotated, such as in a right hand direction (i.e., clockwise looking down into the borehole). As the slip assembly  216  rotates relative to the mandrel  212 , the locking ring  230  may also rotate relative to the mandrel  212  and the threaded interface between the locking ring  230  and the mandrel  212  may cause the locking ring  230  to move longitudinally upwards, toward the lower wedge  228 . As the locking ring  230  is forced longitudinally upward, toward the lower wedge  228 , the fluid space  238  between the locking ring  230  and the lower wedge  228  may become smaller and the fluid may be expelled from the fluid space  238  as the locking ring  230  contacts the lower wedge  228 . Upon being directed toward and contacting the lower wedge  228 , the locking ring  230  will provide additional force to the lower wedge  228  as torque is applied to the slips  222  by the casing as the mandrel  212  is rotated and will also prevent the slip assembly  216  from rotating relative to the mandrel  212 . In view of this, as torque applied to the slips  222  is increased, the axial force applied by the slips  222  to the inner surface of the casing may be increased and the casing spear  200  may effectively rotate the casing. 
     To remove the casing spear  200 , the mandrel  212  may be rotated in the opposite direction, such as in a left-hand direction (i.e., counter-clockwise looking down into the borehole), which may cause the locking ring  230  to rotate relative to the mandrel  212  and be forced axially downward, away from the slips  222 . Additionally, the pumping of drilling fluid may be ceased, or the pressure reduced, and the helical compression spring  232  may force the lower wedge  228  axially downward, toward the locking ring  230  and away from the upper wedge  226  and the slips  222 . As the lower wedge  228  is moved axially away from the upper wedge  226 , the slips  222  may retract axially toward the mandrel  212  to the run-in position, and the casing spear  200  may be removed from the casing. 
     In an additional embodiment, such as shown in  FIGS. 9A-9C , a casing spear  300  may comprise a mandrel  312 , a circumferential stop collar  314 , a slip assembly  316 , and a cup type packer  318 . The mandrel  312  may include a longitudinal fluid passage  320  ( FIGS. 9B and 9C ) extending therethrough and the mandrel  312  may be coupled to the cup type packer  318 , as shown. Additionally, the mandrel  312  may include a stop ring  322  ( FIGS. 9B and 9C ) extending radially outward therefrom. 
     The circumferential stop collar  314  may be coupled to the slip assembly  316 , which may include a plurality of slips  324 , an outer housing  326 , a locking ring  328 , a biasing member  330  ( FIGS. 9B and 9C ) and a retaining ring  332 . The outer housing  326  may be positioned on the mandrel  312 , over the stop ring  322  and each of the slips  324  may be positioned within the outer housing  326  and portions of the slips  324  may extend through corresponding apertures in the outer housing  326 . Each of the slips  324  may include an end surface  334  abutting the stop ring  322  of the mandrel  312  and an opposing wedged end  336  overlying an angled surface  338  (i.e., at an acute angle relative to the longitudinal axis of the mandrel) of the outer housing  326 . Each slip  324  may additionally include a set of protrusions  340  ( FIG. 10 ) corresponding to tracks  342  in the outer housing  326 , which may limit movement of the slips  324  relative to the outer housing  326  to a substantially linear motion. The outer surfaces  344  of the slips may comprise gripping structures. Such gripping structures may comprise, by way of non-limiting example, machined teeth, wickers, crushed tungsten carbide, tungsten carbide inserts in the form of bricks, buttons or discs (which may be inserted into pockets  346 ), superabrasive elements such as natural or polycrystalline diamond, or a combination thereof. 
     The locking ring  328  may be positioned within the outer housing  326 , between the outer housing  326  and the mandrel  312 . The locking ring  328  may include a threaded region  348  mating with a corresponding threaded region of the mandrel  312 . A linear slide  350  may limit motion of the locking ring  328  relative to the outer housing  326  to linear motion in an axial direction. For example, the outer housing  326  may include slots positioned over the locking ring  328 , and corresponding pins (e.g., cap screws), or other axially protruding features, coupled to the locking ring  328  may extend into the slots, respectively. 
     The biasing member  330 , such as a helical compression spring, as shown, may be contained within the outer housing  326  and held against the slips  324  by the retaining ring  332 , which may be coupled to the outer housing  326 . In view of this, the biasing member  330  may bias the slips  324  towards the stop ring  322  of the mandrel  312 . 
     In a run-in position, such as shown in  FIGS. 9A and 9B , the casing spear  300  may be inserted into a casing, which may be made up with another casing positioned in a well bore similarly as described with reference to  FIG. 3 , and the top of the casing may come into contact with the circumferential stop collar  314 . As set down weight is applied to the casing, the casing may apply an opposing upward force on the circumferential stop collar  314  and prevent the circumferential stop collar  314 , and attached outer housing  326  of the slip assembly  316 , from moving axially downward as the mandrel  312  continues to move axially downward relative to the circumferential stop collar  314 , the outer housing  326  of the slip assembly  316 , and the casing. The stop ring  322  of the mandrel  312  may apply an axially downward force to the slips  324 , which may compress the biasing member  330  and may cause the slips  324  to move axially downward relative to the outer housing  326  of the slip assembly  316 . As the slips  324  are moved axially downward relative to the outer housing  326  the protrusions  340  of the slips  324  may move linearly along the tracks  342  of the outer housing  326  and the wedged ends  336  of the slips  324  may move along the angled surfaces  338  of the outer housing  326 , which will cause the slips  324  to be urged radially outward to a set position, as shown in  FIG. 9C , and into contact with an inner surface of the casing. The mandrel  312  may then be rotated, such as in a right hand direction (i.e., clockwise looking down into the borehole), and the contact between the slips  324  and the inner surface of the casing may cause the mandrel  312  to rotate relative to the slip assembly  316  (optionally the mandrel  312  may also be rotated prior to the slips  324  contacting the inner surface of the casing). As the mandrel  312  rotates relative to the slip assembly  316 , the threaded connection between the locking ring  328  and the mandrel  312  may cause the locking ring  328  to be urged axially upward relative to the mandrel  312 , and the outer housing  316  and circumferential stop  314  of the slip assembly  316 . As the locking ring  328  moves axially upward it may contact either the outer housing  326  and/or the circumferential stop ring  314  and apply an axially upward force on the outer housing  326 . After the locking ring  328  is moved axially upward and applies a force to the outer housing  326 , the outer housing  326  may be prevented from any substantial rotation relative to the mandrel  312 . In view of this, the torsion applied to the slips  324  by the casing (countering the rotational force applied by the mandrel  312 ) may cause the locking ring  328  to apply additional force to the outer housing  326 , which may, in turn, apply additional force to urge the slips  324  radially outward to grip the casing. In view of this, as torque applied to the slips  324  is increased, the axial force applied by the slips  324  to the inner surface of the casing may be increased and the casing spear  300  may effectively rotate the casing. 
     To remove the casing spear  300  from the casing, at least a portion of the set down weight may be taken off of the casing spear  300  and the mandrel  312  may be rotated in the opposite direction, such as in a left hand direction (i.e., counter-clockwise looking down into the borehole). The reverse rotation of the mandrel  312  may cause the slip assembly  316 , including the locking ring  328  to rotate in the opposite direction relative to the mandrel  312 . The threaded connection between the locking ring  328  and the mandrel  312  may cause the locking ring  328  to be urged axially downward. As the locking ring  328  is urged downward, the force holding the outer housing  326  may be alleviated and the outer housing may move axially downward relative to the mandrel  312 . Meanwhile, the biasing member  330  may continue to urge the slips  324  against the stop ring  322  as the outer housing  326  moves axially downward and the slips  324  may be urged axially inward, away from the inner surface of the casing to the run-in position. After the slips  324  have retracted axially toward the mandrel  312 , away from the inner surface of the casing, the casing spear  300  may be removed from the casing. 
     While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention only be limited in terms of the appended claims and their legal equivalents.

Technology Classification (CPC): 4