Patent Publication Number: US-8528650-B1

Title: Mandrel casing hanger and running tool system

Description:
RELATED APPLICATION 
     This Application claims the benefit, and priority benefit, of U.S. Patent Application Ser. No. 61/307,736, filed Feb. 24, 2010, entitled “Mandrel Casing Hanger and Running Tool System”. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a mandrel casing hanger and running tool system for use with a casing string in casing operations in a borehole of a well for producing hydrocarbons. 
     2. Description of the Related Art 
     Various mandrel casing hangers and running tools have been previously used in casing operations. When a casing string is run into a well, or borehole, the casing string movement is generally limited to only vertical reciprocation movement. Rotation of the casing string to the right is limited due to concerns about applying too much torque to the connections in the casing string. Rotation of the casing string to the left is limited due to concerns about over backing off, or unthreading, connections in the casing string. 
     SUMMARY OF THE INVENTION 
     In accordance with the illustrative embodiments hereinafter described, the present mandrel casing hanger and running tool system may include: a mandrel casing hanger, a running tool therefor, and a selectively engageable connection between the mandrel casing hanger and the running tool, whereby the mandrel casing hanger and running tool may be rotated in a clockwise direction, or to the right, without any substantial tightening of a threaded connection between the mandrel casing hanger and the running tool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The present mandrel casing hanger and running tool system may be understood by reference to the following description taken in conjunction with the accompanying drawing, in which: 
         FIG. 1  is a perspective view of an illustrative embodiment of the present system; 
         FIG. 2  is a perspective view of an embodiment of the casing mandrel casing hanger of the present system of  FIG. 1 ; 
         FIG. 3  is a perspective view of an embodiment of the running tool of the present system of  FIG. 1 ; 
         FIG. 4  is a top view of the system of  FIG. 1 ; 
         FIG. 5  is a bottom view of the system of  FIG. 1 , with two retaining screws removed; 
         FIG. 6  is a partial cross-sectional view of an embodiment of the present system of  FIG. 1 , taken along line  6 - 6  of  FIG. 5 , with two retaining screws removed; 
         FIG. 7  is a partial cross-sectional view of the present system of  FIG. 1 , taken along line  7 - 7  of  FIG. 5 ; and 
         FIG. 8  is a partial cross-sectional view of the present system of  FIG. 1 , similar to 
         FIG. 6 , which includes a retaining screw. 
     
    
    
     While certain embodiments of the present mandrel casing hanger and running tool system will be described in connection with the preferred illustrative embodiments shown herein, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. In the drawing figures, which are not to scale, the same reference numerals are used throughout the description and in the drawing figures for components and elements having the same structure, and primed reference numerals are used for components and elements having a similar function and construction to those components and elements having the same unprimed reference numerals. 
     DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS 
     With reference to  FIGS. 1-8 , an illustrative embodiment of a mandrel casing hanger and running tool system  100  is illustrated, which is intended for use in casing operations in a borehole, or well, for the production of hydrocarbons, and generally includes a running tool  200  and a mandrel casing hanger  300 . The running tool  200  includes an internal, right-handed set of threads  210  ( FIG. 3 ), which are threadedly engageable with a mating external right-handed set of threads  310  ( FIG. 2 ) on, or associated with, the mandrel casing hanger, or casing hanger,  300 . Mandrel casing hanger preferably includes a set of internal threads  330  ( FIG. 7 ) adjacent its lower end for receiving the externally threaded end, or male threaded end, of a length of conventional casing (not shown), which is part of a casing string, or string of casing, suspended from the casing hanger  300 . The running tool  200  is releaseably attached, or threadeadly connected, to the casing hanger  300  by the threaded engagement of threads  210  and  310  ( FIGS. 2 and 3 ), upon casing hanger  300  being received within running tool  200 , and relative rotational movement being provided between casing hanger  300  and running tool  200 . 
     Running tool generally includes a generally cylindrical shaped body member  201  having an annular shaped housing  202  disposed at the lower end of body member  201 , as seen in  FIGS. 1 ,  3 , and  6 - 8 . Casing hanger  300  generally includes a generally cylindrical shaped body member  301  having an annular shaped flange member, or flange,  302  disposed adjacent the lower end of the body member  301 , as shown in  FIG. 2 . As shown in  FIGS. 1 and 7 , body member  201  of running tool  200  generally receives body member  301  of casing hanger  300 , with flange  302  of casing hanger  300  abutting the lower end of annular housing  202  of running tool  200 . 
     At least four, and preferably a plurality of, milled slots, or slots,  320  are formed in the flange face  321  of flange  302  of the casing hanger  300  ( FIG. 2 ). The plurality of slots are radially spaced about flange  302 , and preferably are equidistantly spaced from each other. For illustrative purposes, eight slots  302  are shown, although a larger or smaller number may be used. Each of the milled slots  320  includes a vertically extending wall surface  322  and an angled, or beveled, wall surface  323 , as shown in  FIGS. 2 and 8 . Wall surfaces  322  are generally disposed in a coplanar relationship with the longitudinal axis of the system  100 , and wall surfaces  323  are generally disposed in an angular, non-coplanar disposition with respect to the longitudinal axis of system  100 . The running tool  200  has at least one, and preferably at least two, retractable, spring loaded, or spring biased, dog members, or dogs,  220  (FIGS.  3  and  6 - 8 ) with associated springs  221  ( FIGS. 6-8 ) disposed within housing  202 . If desired, a greater number of dogs  220  may be used. The dogs  220  are initially fixed within running tool  200  in their retracted configuration, with the springs  221  compressed, by use of retaining screws  230 , as shown in  FIGS. 2 ,  4  and  8 . Upon the removal of the retaining screws  230 , the springs  221  expand and the dogs  220  move downwardly and outwardly of housing  202  into their expanded, slot-engaging configuration shown in  FIGS. 6 and 7 , with dogs  220  engaging slots  320  of casing hanger  300 . A guide pin  235  ( FIGS. 6 and 8 ) may be used to align and guide the movement of each of the dogs  220 . 
     As shown in  FIGS. 3 and 6 , each of the dogs  220  has a vertically extending wall surface  222  which may be disposed adjacent, or abut, wall surface  322  of slots  320  in casing hanger  300 , when dogs  220  are in their expanded, slot-engaging configuration of  FIGS. 6 and 7 . Each of the dogs  220  also have an angled, or beveled wall surface  223  which may be disposed adjacent to, and generally conforms to the shape of, the angled, or beveled wall surface  323  of the slots  320  in casing hanger  300 . Wall surfaces  222  are generally disposed in a coplanar relationship with the longitudinal axis of the system  100  and the wall surfaces  223  are generally disposed in an angular, non-coplanar disposition with respect to the longitudinal axis of system  100 . The running tool  200  and casing hanger may be provided with a plurality of mating fluid bypass passageways  400 ,  400 ′ ( FIGS. 2-4 ). 
     As will be hereinafter described in greater detail, the running tool  200  may be attached to the casing hanger  300  with the right handed sets of threads  210 ,  310 . Any torque generated from rotating the casing string (not shown) while running the casing hanger  300  is transmitted through the retractable, spring loaded dogs  220  in the bottom of the running tool  200  to the vertical extending wall surface  322  of the milled slots  320  in the flange face  321  of the casing hanger  300 . 
     To attach the running tool  200  to the casing hanger  300 , the dogs  220  are initially retracted up into the bottom of the running tool  200  and held in place with the retaining screws  230 . The running tool  200  is then screwed onto the casing hanger  300  using the right hand Acme running threads  210 ,  310  until the running tool  200  and casing hanger  300  are brought to a positive stop. The dog retaining screws  230  are then removed and the running tool is turned to the left, or counter-clockwise when viewed from the top of system  100 , until the dogs  220  spring downwardly into, or in engagement with, the milled slots  320  in the flange face  321  of the casing hanger  300 . 
     The mandrel casing hanger and running tool system  100  is then made up into the casing string (not shown), as by threading an end of the casing string into the set of threads  330  of casing hanger  300  The system  100  and casing string is then run through the stack (not shown) to land the casing hanger  300  on the load shoulder in the casing head (not shown) in a conventional manner. If the casing string is rotated to the right, or clockwise when viewed from the top of system  100 , while running the mandrel casing hanger  300 , the vertical wall surfaces  222  of the running tool dogs  220  engage with the milled slots  320  of the hanger  300 , as by abutting the vertical wall surfaces  322  of slots  320 , and transmit the torque directly from the dogs  220  to the milled slots  320 , therefore substantially bypassing the running tool threaded connection between threads  210  of running tool  200  and threads  310  of hanger  300 . Once the casing hanger  300  is landed, the running tool  200  may be rotated to the left, or counter-clockwise when viewed from the top of system  100 , thus unscrewing the running tool  200  from the casing hanger  300 . The beveled wall surfaces  223  of the retractable dogs  220  slide upwardly and over the beveled wall surfaces  323  of the milled slots  320  in the hanger flange  302 , so that as the running tool  200  rotates to the left, or counter-clockwise, the dogs  220  will initially enter the slots  320  and then will retract from the slots  320  back into the housing  202  of the running tool  200 . 
     Thus, if it is desired to rotate the casing string, as for example, in highly deviated boreholes, resulting from horizontally directional drilling operations, it is possible to rotate the casing string in a clockwise, or right handed direction, when viewed from the upper end of the casing string, or system  100 , in order to get the casing fully installed in the well. This right hand rotation may be obtained without applying an excessive amount of torque to, and without any substantial tightening of, the threaded connection of the sets of threads  210 ,  310  between the running tool  200  and the casing hanger  300 , whereby the running tool  200  and casing hanger  300  may be easily disassembled, or disengaged, from one another after the casing string and casing hanger  300  have been landed in the casing head. 
     Specific embodiments of the present mandrel casing hanger and running tool system have been described and illustrated. It will be understood to those skilled in the art that changes and modifications may be made without departing from the spirit and scope of the inventions defined by the appended claims.