Abstract:
An improved weight-set hanger system and method of securing the weight set hanger for use comprises three independent locking mechanisms that are built into an actuator/packoff assembly. These independent locking mechanisms comprise two locking rings, one of which fastens the actuator/packoff assembly to a spool body, and the other of which internally locks the hanger to the actuator/packoff assembly. A third locking mechanism comprises a plurality of screw down spring loaded lock pin assemblies, which, in an embodiment, are spaced out at 90 degree intervals. No rotation of the seals or other manual intervention is required, which results in significant improvements to lessen the required maintenance and replacement cost.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a non-provisional application that claims the benefit and priority from Provisional U.S. Patent Application No. 62/214,754, filed Sep. 4, 2015, titled “Weight-Set Mandrel and Tubing Hanger,” which is incorporated in its entirety herein by reference. 
     
    
     FIELD 
       [0002]    Embodiments usable within the scope of the present disclosure relate, generally, to a simplified weight-set hanger system requiring no manual intervention. 
       BACKGROUND 
       [0003]    It is common in the oil &amp; gas industry for casing and tubing hangers to depend upon the installation of threaded connections, such as lockdown screws and/or threaded locking rings. 
         [0004]    However, these connections often require painstaking manual intervention, and the use of threaded connections limits the stability. For instance, threaded connections often require rotation of the packoff assembly, which introduces a chance for wellhead seals to be damaged. Additionally, these threaded parts must be replaced often due to wear and tear, which can raise the cost of wellhead operations. 
         [0005]    A need exists for a simplified system that can lock a casing or tubing hanger off a wellhead without the use of threaded lockdown screws, while minimizing rotation of lock rings, and still providing the needed stability and ease of maintenance. 
         [0006]    Embodiments of the apparatus described herein meet this and other needs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    In the detailed description of the embodiments, presented below, reference is made to the accompanying drawings: 
           [0008]      FIG. 1  depicts an overall cross-section view of the actuator packoff assembly. 
           [0009]      FIG. 2A  depicts a zoomed-in view of the packoff ring assembly and the actuator ring assembly in the unlocked position. 
           [0010]      FIG. 2B  depicts a zoomed in view of the packoff ring assembly and the actuator ring assembly in the locked position. 
       
    
    
       [0011]    One or more embodiments are described below with reference to the listed Figures. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0012]    Before describing selected embodiments of the present disclosure in detail, it is to be understood that the present invention is not limited to the particular embodiments described herein. The disclosure and description herein is illustrative and explanatory of one or more presently preferred embodiments and variations thereof, and it will be appreciated by those skilled in the art that various changes in the design, organization, order of operation, means of operation, equipment structures and location, methodology, and use of mechanical equivalents may be made without departing from the spirit of the invention. 
         [0013]    As well, it should be understood the drawings are intended to illustrate and plainly disclose presently preferred embodiments to one of skill in the art, but are not intended to be manufacturing level drawings or renditions of final products and may include simplified conceptual views as desired for easier and quicker understanding or explanation. As well, the relative size and arrangement of the components may differ from that shown and still operate within the spirit of the invention. 
         [0014]    Moreover, it will be understood that various directions such as “upper,” “lower,” “bottom,” “top,” “left,” “right,” and so forth are made only with respect to explanation in conjunction with the drawings, and that the components may be oriented differently, for instance, during transportation and manufacturing as well as operation. Because many varying and different embodiments may be made within the scope of the concept(s) herein taught, and because many modifications may be made in the embodiments described herein, it is to be understood that the details herein are to be interpreted as illustrative and non-limiting. 
         [0015]    Referring to  FIG. 1 , the depicted embodiment of the invention comprises three separate locking devices built into a single actuator/packoff assembly  10 . Actuator/packoff assembly  10  comprises an actuator ring  20  located above packoff body  30 , as well as an upper lock ring  40 , a lower lock ring  41 , and a plurality of screw dog spring loaded lock pin assemblies  45 . While the embodiment is depicted with two such lock pin assemblies  45  visible in cross-section, it should be noted that the depicted embodiment also comprises two additional lock pin assemblies  45  (not visible in cross-section), with a total of four arranged at 90 degree intervals. Screw dog spring loaded lock pin assemblies  45  can act as both spring loaded lock pin assemblies and screw dog pins for running and retrieval of the actuator packoff assembly  10 . (For simplicity,  FIG. 1  is numbered only on one side; numbers are duplicated as visible in  FIG. 2A-2B .) 
         [0016]    As shown, actuator/packoff assembly  10  can be positioned between the outer diameter of a hanger  13  and an inner diameter of a spool body  11  (which may be a casing spool body or a tubing spool body). As further shown in the depicted embodiment, spool body  11  can comprise at least one locking groove  12 , which can be positioned around the inner diameter of the spool body  11 , while hanger  13  can comprise two locking grooves  14 ,  15 , which can be positioned along the outer diameter thereof. Hanger  13  may be a tubing hanger, a fluted mandrel casing hanger, or any other suitable hanger, provided that two locking grooves  14 ,  15  are present on the hanger outer diameter. 
         [0017]    As shown, upper lock ring  40  can be positioned on the first shoulder  31  (identified in  FIG. 2A-2B ) of the packoff body  30  next to an angled face  21  (identified in  FIG. 2A-2B ) of the actuator ring  20 . Upper lock ring  40  is expandable upon the application of pressure, at which point upper lock ring  40  can be captured by locking groove  14  of hanger  13 . Lower lock ring  41 , as shown, can be expandable and positioned along a second shoulder  32  (identified in  FIG. 2A-2B ) of the packoff body  30  and a second angled face  22  (identified in  FIG. 2A-2B ) of actuator ring  20 , and can be captured into position by locking groove  12  of spool body  11 . In an embodiment, the first locking ring can provide a ninety percent (90%) circumferential lock, while the second locking ring can provide a ninety-five percent (95%) circumferential lock. However, other embodiments may provide more or less circumferential coverage, as necessitated by well conditions. Lock pin assemblies  45 , as shown, can be captured by locking groove  15  of hanger  13 . Packoff ring  30  is fitted with a plurality of s-seals  33  for sealing against both the spool body  11  and the hanger  13 . 
         [0018]    Prior to use, packoff body  30  and actuator ring  20  can be assembled together and held in the unlocked position by attachment shear pins (not shown). A plurality of alignment screws  25  can be screwed into actuator ring  20  through machined slots  34  within packoff body  30  to ensure alignment during running and retrieval. It should be appreciated that in this embodiment, these machined slots  34  are shown in this particular cross-section, but do not extend concentrically around the packoff assembly  30 . Thus, packoff assembly  30  and first shoulder  31  appear to be separate components in this diagram but are actually parts of the same component. 
         [0019]    Referring now to  FIGS. 2A and 2B , the use of the actuator/packoff assembly  10  is illustrated in practice. Actuator/packoff assembly  10  can be run into position by industry standard running and retrieval tools that can, for example, utilize a J-slot type function that can be aligned with the screw dog spring loaded lock pin assemblies  45 . As shown, actuator/packoff assembly  10  lands on the shoulder  16  (shown in  FIG. 1 ) of hanger  13 , which can rest on an inner diameter of the spool body  11 .  FIG. 2A  depicts the actuator-pack off assembly  10  in an unlocked position for running/retrieval. 
         [0020]    Once landed, the full weight of the tubing/casing string can be loaded onto the running and retrieval tool, which results in an downward stabbing force shearing the two attachment shear pins (not shown), and a downward force being applied onto the actuator/packoff assembly  10 , which pushes the actuator ring  20  down towards the packoff body  30 , which is braced against a shoulder  16  of the hanger  13 . It can be seen that the respective angled faces  21 ,  22  of the actuator ring  20  can act to force the respective locking rings  40 ,  41  away from the actuator ring, into respective grooves  14 ,  12  of respective hanger  13  and spool body  11 . Lock pin assemblies  45 , such as screw dog spring loaded lock pin assemblies  45 , can then spring out from the J-slot and lock into groove  15  of hanger  13 . 
         [0021]      FIG. 2B  depicts the actuator/packoff assembly  10  in its locked state with the attachment shear pins (not shown) sheared, and actuator ring  20  lowered by the stabbing force with respect to packoff body  30 . The running/retrieval tool can then be rotated to release the actuator/packoff assembly  10  and withdrawn. 
         [0022]    During retrieval, the running/retrieval tool can interface with the screw dog spring loaded lock pin assemblies  45 , which can be aligned with a J-slot (or other suitable retrieval mechanism) and pulled upwards with an over-pull (e.g., in an embodiment, this over-pull force can be roughly equal to 20,000 lbs or 9,000 kg). This action can shear the screw dog spring loaded lock pin assemblies  45 , separate the actuator ring  20  from the packoff body  30 , and allow the locking rings  40 ,  41  to withdraw from their respective grooves  14 ,  12 . 
         [0023]    The design described herein yields several advantages over existing hanger assemblies. As there is no rotation of the actuator/packoff assembly itself, only the running and retrieval tool, the chances of seal damage are minimized while ensuring that the hanger remains safely locked during tubing and casing running operations. Installation and retrieval requires little or no maintenance or manual intervention, and the cost of replacement parts amounts to, in a preferred embodiment, a total of six shear pins (i.e., two on running being sheared by push force and four on retrieval being sheared by over-pull). 
         [0024]    Although several preferred embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing specification, it will be understood by those of skill in the art that additional embodiments, modifications and alterations may be constructed from the invention principles disclosed herein, while still falling within the scope of the disclosed invention.