Abstract:
A wellhead adapter configuration includes a body configured and dimensioned to attach to a wellhead. An inside dimension sufficient to allow through passage of a casing hanger. A method for preparing a borehole.

Description:
BACKGROUND 
       [0001]    Boreholes into the subsurface environment of a planet such as earth, whether for hydrocarbon exploration and recovery, carbon dioxide sequestration, etc., employ borehole capping structures known colloquially as well heads. Well heads serve to hang various casing strings and provide mounting locations for other accessories such as Christmas trees, blow out preventers, etc. Commonly, the manufacturer of the wellhead will configure the same to receive a tubing hanger supplied by the same manufacturer. This is, of course, supportive of that manufacturers interest in selling more equipment but does not necessarily support the interests of the well operator, who might prefer to run another manufacturer&#39;s tubing hanger for a host of reasons. 
         [0002]    In view hereof, the industry has created a tool known colloquially as a wellhead adapter. The tool is fittable into the top of the well head and provides for the use of another manufacturer&#39;s tubing hanger. These work well to allow the well operator to use tubing hangers from whatever manufacturer having features in which the owner has a particular interest for the particular well or whatever manufacture&#39;s tubing hanger that the well operator happens to have in stock. The ability to run a selected tubing hanger also enables the well owner to commoditize the tubing hangers in order to buy in bulk. These benefits of the wellhead adapters make them popular and have for a long time obscured the costs of actually running a wellhead adaptor. To use the adapter, several trips are needed that generally take about 3 weeks of running time in various runs before the operation is complete. Costs can run into the millions of dollars but because of commodity purchasing of the various wellhead components, the industry has had no difficulty with the current state of affairs. 
         [0003]    Despite the industry acceptance of the paradigm noted above, it is always receptive to the ruminations of intrepid souls who conceive and devise new methods and configurations that reduce time and expenditure in the completion of borehole systems. 
       BRIEF DESCRIPTION 
       [0004]    A wellhead adapter configuration includes a body configured and dimensioned to attach to a wellhead; an inside dimension sufficient to allow through passage of a casing hanger. 
         [0005]    A method for preparing a borehole includes running a wellhead adapter either with or subsequent to the running of a wellhead, the wellhead adapter having an inside dimension sufficient to allow through passage of a casing hanger; running a casing and casing hanger to the wellhead through the wellhead adapter; running a tubing and tubing hanger and landing shoulder into the wellhead adapter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0007]      FIG. 1  is a schematic cross section view of a wellhead and a tubing hanger conversion configuration; 
           [0008]      FIG. 2  adds a casing, a casing hanger and a BOP to the image of  FIG. 1 ; 
           [0009]      FIG. 3  adds a spacer/landing shoulder and a tubing and tubing hanger to the image of  FIG. 2 ; 
           [0010]      FIG. 4  illustrates the above components in a landed position; 
           [0011]      FIG. 5-8  are a repeat of  FIGS. 1-4  with changes related to a second embodiment 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0013]    Referring to  FIG. 1-4  a first embodiment is illustrated.  FIG. 1  schematically illustrates earth surface  10  with a wellhead  12  penetrating to the subsurface environment. Attached to the wellhead  12  is a wellhead adapter  14 . The wellhead adapter  14  and wellhead  12  are connected together by, for example, an H4 connector (commercially available from Aker Solutions Incorporated, Houston Tex.). The combination is then run to position together (although in other embodiments, running the wellhead adapter after the wellhead is run is contemplated). It is important to note that an inside dimension  16  of the wellhead adapter  14  maintains the inside dimension of the wellhead  12 . This allows for running of a casing  18  and casing hanger  20  through the wellhead adapter  14  which has not heretofore been possible. This is significant because it allows for the above noted running of the wellhead adapter with the well head in a single run. In the art, such would have taken at least 4 runs as one of skill in the art will readily recognize, configurations that eliminate runs are economically beneficial to the art. 
         [0014]      FIG. 2  illustrates a casing  18  hung from casing hanger  20  in the wellhead  12 . Further a BOP  22  is illustrated atop the conversion configuration  14  in this Figure. The BOP (Blowout Preventer) is run and connected atop the wellhead adapter (via another connector  13  such as an H4 connector, in a single run. The BOP  22 , casing  18  and casing hanger  20  are run during the drilling operation, which as one of skill in the art knows will naturally have to occur during the sequence of preparing the borehole for its intended end use. 
         [0015]    Referring to  FIG. 3 , and in another run, tubing  24  and tubing hanger  26  are illustrated while being conveyed into the wellhead adapter  14  and the wellhead  12 . Further a spacer  28  is positioned at the tubing hanger to space the tubing hanger  26  from the casing hanger  20  (previously installed) by a selected distance. In  FIG. 4 , all components are illustrated in a landed position. 
         [0016]    In another embodiment, referring to  FIGS. 5-8 , and wherein like elements carry the same numerals as above and similar elements to those above are referred to with one hundred series numerals of the numerals used above, the wellhead adapter  114  is provided additionally with a profile  130  therein that is configured to be engaged by a landing shoulder  132  run in subsequently with the tubing hanger  126 . The profile  130  extends generally radially outwardly from a wall  131  of the wellhead adapter that defines the inside dimension of the wellhead adapter. The landing shoulder  132  may comprise a snap ring, collet or other expanding configuration with the capability of expanding into profile  130  in wellhead adapter  114  to lock the landing shoulder  132  in place. The profile  130  may comprise any selected shape from a simple snap ring groove to a complex profile configuration and anything in between with the caveat that once the landing shoulder  132  engages therewith, the shoulder will be located sufficiently to support adequate positioning of the tubing hanger  26 . With this embodiment, there is no need for spacer  28  illustrated in conjunction with the previously described embodiment. In other respects this embodiment is identical to that of the previous embodiment. 
         [0017]    Through the teachings hereof, the following method is enabled: running a first manufacturer&#39;s wellhead either with a wellhead adapter as described above or prior to running the wellhead adapter as described above, connecting the wellhead adapter to the wellhead; running a casing and casing hanger through the wellhead adapter to land in the wellhead; and running a tubing and tubing hanger from a manufacturer different than the first manufacturer to land in the wellhead adapter. Also enabled is the method of providing a landing shoulder for the tubing hanger either by a spacer landing upon the casing hanger or by a profile engaged by an enlarging configuration such as a snap ring or collet. 
         [0018]    Great benefit to the art is realized by the teachings herein in that different OEM equipment may be used for the wellhead and the tubing hanger while substantially cutting down the number of runs and time needed to accomplish the conversion. 
         [0019]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.