Abstract:
An apparatus and methods for manipulating and driving casing. The apparatus includes mechanically responsive elements for gripping an interior of a casing joint, and hydraulically responsive elements for gripping an interior of the casing joint responsive to pressure of drilling fluid flowing through the apparatus. One method comprises manipulating a casing joint by mechanically gripping an interior thereof, hydraulically gripping the interior of the casing joint responsive to drilling fluid pressure, and rotating the casing joint. Another method comprises driving casing by applying weight and torque thereto through engagement with an interior thereof.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 12/869,479 filed on Aug. 26, 2010, which claims the benefit of U.S. Provisional Patent Application No. 61/237,572 entitled “METHODS AND APPARATUS FOR MANIPULATING AND DRIVING CASING,” filed Aug. 27, 2009, the disclosure of which is incorporated herein in its entirety by this reference. 
     
    
     TECHNICAL FIELD 
       [0002]    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 
       [0003]    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. 
         [0004]    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. 
         [0005]    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. 
       BRIEF SUMMARY 
       [0006]    In one embodiment, the present invention comprises a casing assembly having a longitudinal passage therethrough in communication with a plurality of circumferentially spaced, radially movable pistons and extending to at least one outlet of the lower end of the assembly, a plurality of selectively mechanically actuable, radially movable slips, a plurality of spring-biased friction blocks longitudinally spaced from the slips, a downward-facing packer cup positioned between the slips and the at least one outlet, and a tapered stabilizer guide below the downward-facing packer cup. 
         [0007]    In another embodiment, the present invention comprises a method of manipulating casing comprising inserting an assembly into an upper end of a casing joint, gripping the casing joint by an interior thereof with the assembly responsive to longitudinal movement of one portion of the assembly with respect to another portion of the assembly, pumping drilling fluid through the assembly to cause the assembly to grip the interior of the casing joint responsive to hydraulic pressure of the drilling fluid, preventing drilling fluid from exiting the upper end of the casing joint, and rotating the casing joint. 
         [0008]    Another embodiment comprises a method of driving casing, including engaging an uppermost casing joint of a casing string having a device with a cutting structure thereon at a lower end thereof substantially only on an interior of the uppermost casing joint, rotating the casing string by application of torque to the interior of the uppermost casing joint and applying weight to the casing string during rotation thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1A  is a partial sectional elevation of a casing drive assembly according to an embodiment of the present invention. 
           [0010]      FIG. 1B  is a detail view of  FIG. 1A  showing a hydraulic anchor of the casing drive assembly. 
           [0011]      FIG. 1C  is a detail view  FIG. 1A  showing a mechanical spacing spear of the casing drive assembly. 
           [0012]      FIG. 1D  is a detail view of  FIG. 1A  showing a cup type packer and a tapered stabilizer of the casing drive assembly. 
           [0013]      FIG. 2  is a schematic of a casing drive assembly, such as shown in  FIG. 1A , disposed within a casing joint of a casing string above another casing joint. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    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. 
         [0015]    While embodiments of the present invention 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 invention. 
         [0016]    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. 
         [0017]    Referring to  FIG. 1A  of the drawings, an embodiment of a casing drive assembly  10  according to the present invention comprises, from an upper to a lower end thereof, a hydraulic anchor  100 , a mechanical casing spear  200 , a cup type packer  300 , and a tapered stabilizer  400 . 
         [0018]    As shown in  FIG. 1B , the hydraulic anchor  100  comprises a housing  102  having a circumferential stop collar  106  about the upper end thereof for limiting insertion of the casing drive assembly  10  into a casing joint. The housing  102  includes a longitudinal passage  104  extending therethrough from top to bottom, in communication with lateral passages  108  extending to the interiors of spring-loaded, inwardly biased pistons  110  in two longitudinally separated groups, each group comprising a plurality of pistons  110  (in this instance, four) equally circumferentially spaced in pockets  112  in the housing  102 . Seals (not shown) enable fluid-tight movement of the pistons  110  in the pockets  112  responsive to a drilling fluid pressure within the longitudinal passage  104 . The pistons  110  comprise gripping structures  114  on exterior surfaces  116  thereof, as is conventional in the art. Such gripping structures  114  may comprise, by way of non-limiting example, machined teeth, 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, gripping structures comprise carbide inserts configured with teeth. 
         [0019]    Secured to the lower end of the hydraulic anchor  100  is the casing spear  200 , which may be configured substantially as a Baker Oil Tools (Tri-State) Type “D” Casing Spear. As shown in  FIG. 1C , the casing spear  200  comprises a mandrel  202  having a longitudinal passage  204  extending therethrough and in communication with the longitudinal passage  104  of the hydraulic anchor  100 . An outer housing  206  is longitudinally slidably and rotationally disposed over the mandrel  202 , longitudinal movement of the outer housing  206  being constrained by engagement of a lug  208  protruding radially from the mandrel  202  through a J-slot  210  having a longitudinally extending segment L and a laterally extending segment LA, the lug  208  extending through the wall of outer housing  206 . A plurality of slips  212  is disposed in a like plurality of slots  214  extending through the outer housing  206 . The slips  212  include lips  216  at longitudinally upper and lower ends thereof to retain the slips  212  within the slots  214 . The interior of the slips  212  comprise a plurality of stepped wedge elements  218  having concave, partial frustoconical radially inner surfaces  220 . The outer surfaces  222  of the slips  212  comprise gripping structures  224 , as is conventional in the art. Such gripping structures  224  may comprise, by way of non-limiting example, machined teeth, 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, gripping structures comprise tungsten carbide inserts in the form of buttons having four projecting, pyramidal points. Two longitudinally extending groups of eight to ten buttons per slip  212  may be employed. 
         [0020]    Inner surfaces  220  of stepped wedge elements  218  are sized and configured to cooperate with stepped convex, frustoconical wedge surfaces  226  on an exterior surface of the mandrel  202  to move the slips  212  radially outwardly responsive to upward movement of the mandrel  202  within the outer housing  206 . A plurality of circumferentially spaced stabilizer friction blocks  228  are radially outwardly biased by springs  230  and are disposed within slots  232  in outer housing  206  and retained therein against the outward spring biased by lips  234  at upper and lower ends of the stabilizer friction blocks  228 . A lower housing  236  is secured to the lower end of the mandrel  202 . 
         [0021]    Secured to the lower housing  236  of the casing spear  200  at the lower end thereof is a packer mandrel  302  of the cup-type packer  300 , as shown in  FIG. 1D , the cup-type packer  300  having a longitudinal passage  304  therethrough in communication with the longitudinal passage  204  of casing spear  200 . A downward-facing, elastomeric, wire mesh-reinforced annular packer cup  308  is disposed over the upper mandrel  302  and retained thereon between an annular support wedge  310  abutting a downward-facing annular shoulder  312  and the upper end of a guide sleeve  314 , from which an annular, radially projecting casing guide  316  projects. The casing guide  316  comprises frustoconical upper and lower surfaces  318 ,  320  longitudinally separated by a cylindrical guide surface  322 , circumferentially spaced, longitudinally extending slots  324  communicating between the upper and lower surfaces  318 ,  320 . 
         [0022]    As further shown in  FIG. 1D , the tapered stabilizer  400  is secured at its upper end  402  to the lower end of the packer mandrel  302 , and includes a longitudinal passage  404  in communication with the longitudinal passage  304  of the cup-type packer  300 . The longitudinal passage  404  extends to, and communicates with, outlet slots  406  extending through an outer surface of a frustoconical, tapered stabilizer guide  408  terminating at a nose  410 . 
         [0023]    In use, and with reference to drawing  FIGS. 1A ,  1 B,  1 C,  1 D and  2 , wherein a casing joint  500  is shown disposed above another casing joint  502 , a single joint of casing  500  is picked up using the rig elevators, as is conventional, and stabbed up into an existing casing joint  502  (if a casing string has already been started). The casing drive assembly  10  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  500  from the top thereof. The elevators stay latched and ride down the casing joint  500  during this operation. Once the casing drive assembly  10  has entered casing joint  500  sufficiently so that stop collar  104  arrests further travel of casing drive assembly  10  into the casing joint  500 , casing joint  500  is rotated to engage casing joint  502 . The casing joint  500  may be run up with the rig tongs or casing drive assembly  10  may be used to transmit rotation to the casing joint  500  once it is fully engaged with casing joint  500 , after engagement with the interior of casing joint  500 , as described below. The tapered stabilizer guide  408 , the casing guide  316  and the spring-biased friction blocks  228  aid insertion and centering of the casing drive assembly  10  into and within the casing joint. 
         [0024]    If the casing joint  500  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 drive assembly  10 . Non-limiting examples of such devices are, for drilling, the EZ Case™ casing bit and, for reaming, the EZ Ream™ shoe. Otherwise, such a device  504  is already secured to the distal end of the lowermost casing joint in the casing string. To initially engage the casing drive assembly  10  with the interior of casing joint  500 , the casing spear  200  is manipulated, as by right-hand (clockwise, looking downward) rotation of the casing drive assembly  10  to move the lug  208  within the laterally extending segment LA of the J-slot  210  and align the lug  208  with the longitudinal segment L of the J-slot  210 , followed by application of an upward force to the casing drive assembly  10 . The spring-biased friction blocks  228  provide sufficient, initial frictional drag against the interior of the casing joint  500  to maintain the outer housing  206  of the casing spear  200  stationary within the casing joint  500  until the gripping structures  224  on the outer surfaces  222  of the slips  212  engage the interior of the casing joint  500  as the stepped convex, frustoconical wedges surfaces  226  of the mandrel  202  move upwardly with respect to the stepped wedge elements  218  on the interior surfaces  220  of the slips  212  and force the slips  212  radially outwardly to securely grip the interior of the casing joint. 
         [0025]    The engaged casing joint  500  is then lifted using the top drive to permit slips of a holding device at the rig floor, commonly termed a “spider,” which are employed to suspend the existing casing string below the rig floor, as is conventional. 
         [0026]    The rig pump may then be engaged and circulation of drilling fluid established through the casing drive assembly  10  through the longitudinal passages  104 ,  204 ,  304  and  404  and out into the interior of the casing joint  500  through the outlet slots  406 . Upward circulation of drilling fluid within the casing joint  500  is precluded by the packer cup  308 , which expands against and seals with the interior of the casing joint  500  under drilling fluid pressure, a prompt and fluid-tight seal being facilitated by the presence of the slots  324  of the casing guide  316 . Drilling fluid pressure is increased until sufficient pressure is observed to cause the pistons  110  of the hydraulic anchor  100  to grip the interior of the casing joint  500 . 
         [0027]    The casing drive assembly  10 , with the casing joint  500  secured thereto by the hydraulic anchor pistons  110 , is then rotated by the top drive to rotate the casing joint  500  and any others therebelow (if any) in the casing string, the top drive also providing weight, and drilling or reaming commences. Notably, both torque and weight are applied to the casing joint  500  via engagement of the casing drive assembly  10  substantially only with the interior of the casing joint  500 . 
         [0028]    The rig elevators remain attached as the casing joint  500  descends until a point just above the rig floor, where they can be reached and released for picking up the next casing joint. When the upper end of the casing joint  500 , engaged by the casing drive assembly  10 , approaches the rig floor, the slips of the spider are then employed to grip the casing joint  500 , drilling fluid circulation ceases, releasing the pistons  110  of the hydraulic anchor  100  from the casing joint under their inward spring-loading, the casing drive assembly  10  is lowered sufficiently to release the slips  210  of the casing spear  200  from the casing joint and rotated slightly to the left (counterclockwise, looking downward) to maintain the release of the slips  212 , and the casing drive assembly  10  is withdrawn from the casing joint  500  for subsequent insertion into another casing joint picked up by the rig elevators, the above-described process then being repeated. 
         [0029]    A significant advantage of the use of a casing drive assembly according to an embodiment of the present invention is reduced casing thread wear, due to the lack of a threaded connection between the casing drive assembly and the casing joint engaged thereby. 
         [0030]    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.