Abstract:
A horizontal production tree for use on a land-based surface well head. The horizontal production tree may be maintained in place on the well head throughout the life of well, even during fracing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and claims the benefit of U.S. Provisional Application Ser. No. 61/425,814, filed Dec. 16, 2010, which is herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention. 
         [0003]    This invention relates generally to oil and gas well production trees, and more particularly to a horizontal production tree for use with oil and gas wells located on land. 
         [0004]    2. Description of the Related Art. 
         [0005]    Producing oil and gas wells frequently utilize production trees to control the flow of oil or gas out of the well. A production tree may also offer additional functions, such as chemical injection points, well intervention means, pressure relief means, tree and well monitoring points, and connection points for devices such as downhole pressure and temperature instrumentation. 
         [0006]    Offshore oil and gas wells often utilize horizontal production trees. These offshore horizontal production trees are highly engineered and have many safeguards. The subsea type of offshore horizontal production trees are made to be operated by a Remotely Operated Vehicle. 
         [0007]    However, horizontal production trees are not used on onshore surface wells. Rather, production trees for onshore surface wells typically have a vertical configuration. Such onshore vertical production trees must be removed from the well to frac the well and reinstalled when fracing is complete. Such removal and reinstallation can be expensive and dangerous and requires specialized machinery. Additionally, the production tree must be removed to run production tubing through and pull tubing out of the well. Furthermore, vertical production trees are large and difficult to repair without climbing, which is dangerous. Such large vertical production trees are also unsightly and undesirable in urban environments. 
         [0008]    It is therefore desirable to provide a horizontal production tree that can be used on onshore surface wells. It is further desirable to provide a horizontal production tree for use with onshore surface wells through which an operator may frac the well and run production tubing through the well without removing the horizontal production tree. It is further desirable to provide a horizontal production tree for use with onshore surface wells that has a compact design allowing for easy repairs and easy concealment from public view in urban environments. 
       SUMMARY OF THE INVENTION 
       [0009]    In general, the invention relates to a horizontal production tree with a body with a body bore extending substantially vertically therethrough, where the body bore has an upper portion with a diameter, a middle portion with a larger diameter than the diameter of the upper portion, and a lower portion. A sloped shoulder may be located between the upper portion and the middle portion of the body bore. A flapper valve gate may fit snugly against the sloped shoulder to prevent fluid in the middle portion of the body bore from traveling to the upper portion of the body bore. An arm with a first end and a second end may be is connected to the flapper valve gate. A stern may be perpendicularly connected to the second end of the arm, such that rotating the stem causes the arm and the flapper valve gate to pivot between a closed position, where the flapper valve gate is flush against the sloped shoulder, and an open position, where the flapper valve gate is not in contact with the sloped shoulder, where the stem has a first end and a second end. A recess may be located in the body extending from the middle portion of the body bore, where the first end of the stem is rotatably mounted with the recess. A channel may be located in the body extending from the middle portion of the body bore, where the stem extends through the channel and exits the body, such that the second end of the stem is located outside the body. The horizontal production tree may be configured such that the horizontal production tree may be connected to a land-based surface well head by mounting the horizontal production tree atop the land-based surface well head such that the horizontal production tree is vertically aligned with and in fluid communication with the land-based surface well head. 
         [0010]    One or more production valves may be in fluid communication with the body bore and extending horizontally from the body. A pressure gage may be in fluid communication with the body bore mounted atop the body via a nut and plug assembly, or a work flange may be in fluid communication with the body bore mounted atop the body via a nut and sealing mechanism with a frac valve in fluid communication with the work flange and mounted atop the work flange. A frac isolation sleeve may be located at least partially within the body bore when the frac valve is. in use. 
         [0011]    The lower portion of the body bore may have a smaller diameter than the middle portion of the body bore, in which case a sloped shoulder may be located between the middle portion and the lower portion. The arm may be connected to the stem via a connector portion of the arm, where the connector portion of the arm runs along a common axis with the stem and has an internal bore into which the stem fits. The body may have a recess extending from the middle portion of the body bore, into which recess the arm may fit when the flapper valve gate is in the open position, such that the flapper valve gate may lie substantially vertically. 
         [0012]    The stem may comprise a lower stem with an internal end and an external end, where the internal end is internally threaded and the external end is the first end of the stem, which is rotatably mounted within the recess in the body extending from the middle portion of the body bore; and an upper stem with an internal end and an external end, where the internal end is externally threaded and may be screwed into the internal end of the lower stem and the external end is the second end of the stem. A bearing race assembly may be integral to the lower stem near its external end, such that the bearing race assembly is located within the recess in the body. One or more additional bearing race assemblies, one or more thrust bearings, or both one or more additional bearing race assemblies and one or more thrust bearings may be placed on the lower stem adjacent the bearing race assembly such that the additional bearing race assemblies and/or thrust bearings are located within the recess in the body. 
         [0013]    The second end of the stem may terminate in a flapper valve bonnet assembly. The flapper valve bonnet assembly may comprise: a flapper valve bonnet attached to the body, where the flapper valve bonnet has an internal bore and the stem extends through the internal bore of the flapper valve bonnet; a valve packing and a packing retainer attached to the flapper valve bonnet, where the packing retainer has an internal bore and the stem extends through the internal bore of the packing retainer; a stem adapter attached to the second end of the stem; a hand wheel attached to the stem adapter, where the hand wheel can be turned to turn the stem adapter and the stem and, resultantly, pivot the flapper valve gate between the open and closed positions; and a bearing cap attached to the flapper valve bonnet and surrounding a portion of the flapper valve bonnet, a portion of the valve packing, and a portion of the stem adapter such that the bearing cap bridges the gaps between those elements. Furthermore, a first locking flange may be attached to the bearing cap; one or more holes may be located in the first locking flange; a second locking flange may be attached to the hand wheel such that the second locking flange abuts the first locking flange; one or more holes may be located in the second locking flange such that the holes in the second locking flange may align with the holes in the first locking flange when the hand wheel is in a particular position; and a locking pin may be inserted through a hole in the first locking flange and a corresponding hole in the second locking flange to prevent the hand wheel from turning relative to the bearing cap. 
         [0014]    A method of using a production tree on a land-based surface well head comprises the steps of: mounting a horizontal production tree, as described above, atop a land-based surface well head such that the horizontal production tree is vertically aligned with and in fluid communication with the land-based surface well head; turning the hand wheel until the flapper valve gate is in the closed position; performing tasks that require the flapper valve gate in the closed position; turning the hand wheel until the flapper valve gate is in the open position; and performing tasks that require the flapper valve gate in the open position. Monitoring the pressure in the horizontal production tree comprises: turning the hand wheel until the flapper valve gate is in the closed position; mounting a pressure gage atop the body of the horizontal production tree via a nut and plug assembly, where the pressure gate is in fluid communication with the upper portion of the body bore of the horizontal production tree; turning the hand wheel until the flapper valve gate is in the open position; and reading the pressure in the horizontal production tree as displayed on the pressure gage. Fracing the well while maintaining the horizontal production tree in place atop the well head comprises: turning the hand wheel until the flapper valve gate is in the closed position; mounting a work flange atop the body of the horizontal production tree via a nut and plug assembly, where the work flange is in fluid communication with the upper portion of the body bore of the horizontal production tree; mounting a frac valve atop the work flange; turning the hand wheel until the flapper valve gate is in the open position; inserting a frac isolation sleeve within the body bore spanning the horizontal production tree and the well head; and fracing the well. Removing an instrument mounted atop the horizontal production tree from the horizontal production tree comprises turning the hand wheel until the flapper valve gate is in the closed position and removing the instrument from atop the horizontal production tree. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a side cut-away view of the horizontal production tree of the present invention; 
           [0016]      FIGS. 2A and 2B  are side cut-away views of the top of the horizontal production tree with the flapper gate in a closed and an open position, respectively; 
           [0017]      FIGS. 3A and 3B  are side cut-away views of the top of the horizontal production tree with the flapper gate in a closed and an open position, respectively, where the view is rotated  90  degrees from the view of  FIGS. 2A and 2B ; 
           [0018]      FIG. 4  is a cut-away perspective view of the hand wheel, stem, and flapper gate elements of the present invention; 
           [0019]      FIG. 5  is an exploded view of the stem of the present invention; and 
           [0020]      FIG. 6  is a side cut-away view of the horizontal production tree of the present invention, shown with a work flange and frac valve mounted atop the horizontal production tree. 
       
    
    
       [0021]    Other advantages and features will be apparent from the following description, and from the claims. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The devices and methods discussed herein are merely illustrative of specific manners in which to make and use this invention and are not to be interpreted as limiting in scope. 
         [0023]    While the devices and methods have been described with a certain degree of particularity, it is to be noted that many modifications may be made in the construction and the arrangement of the structural and functional details disclosed herein without departing from the spirit and scope of this disclosure. It is understood that the devices and methods are not limited to the embodiments set forth herein for purposes of exemplification. 
         [0024]    Referring to the figures of the drawings, wherein like numerals of reference designate like elements throughout the several views, and initially to  FIG. 1 , a horizontal production tree  1  is mounted atop a standard practice well head  2 . Production valves  3  may extend from a body  4  of the horizontal production tree  1 . A body bore  5  may extend vertically through the body  4  of the horizontal production tree  1 , allowing for the horizontal production tree  1  to fluidly connect to the well head  2  at its lower end. Fluidly connected via the body bore  5  to the upper end of the horizontal production tree  1  may be a nut and plug assembly  6 . The nut and plug assembly  6  may remain flanged up during the life of the well unless the horizontal production tree  1  is damaged. 
         [0025]    The nut and plug assembly  6  allows a user to connect a variety of instruments to the horizontal production tree  1  for varied purposes. For example, in  FIG. 1 , a pressure gage  7  is connected to the nut and plug assembly  6 . This configuration is. used to monitor the pressure in the horizontal production tree  1 . In  FIG. 6 , a work flange  8  is connected to the nut and plug assembly  6  with its own nut and sealing mechanism, with a frac valve  9  connected to the work flange  8 . This configuration allows for fracing through the frac valve  9  without removing the horizontal production tree  1  from the well head  2 . A frac isolation sleeve  10  may be placed within the body bore  5  spanning the horizontal production tree  1  and the well head  2  to protect the horizontal production tree  1  during fracing. 
         [0026]    The body bore  5  may have an upper portion  11 , a middle portion  12 , and a lower portion  13 , where the upper portion  11  has a smaller diameter than the middle portion  12  and the middle portion  12  has a larger diameter than the lower portion  13 . A sloped shoulder  14  bridges the middle portion  12  and the lower portion  13 , allowing for easy entry of tubing and tools through the body bore  5 . A sloped shoulder  15  also bridges the upper portion  11  and the middle portion  12 . A flapper valve gate  16  may fit snugly against the sloped shoulder  15  to prevent fluid from the well from traveling through middle portion  12  of the body bore  5  to the upper portion  11  of the body bore  5 , and ultimately entering the nut and plug assembly  6 . The flapper valve gate  16  may be made of polyteflon or other suitable material to form a seal against the sloped shoulder  15 . 
         [0027]    The flapper valve gate  16  may be connected to an arm  17 , allowing the flapper valve gate  16  to pivot between a closed position, where the flapper valve gate  16  is flush against the sloped shoulder  15  and prevents all fluids from traveling through middle portion  12  to upper portion  11 , and an open position, where the flapper valve gate  16  is not in contact with the sloped shoulder  15  and does not inhibit the travel of fluid from the middle portion  12  to the upper portion  11 . The closed position is shown in  FIG. 2A  and the open position is shown in  FIG. 2B . The middle portion  12  of the body bore  5  may have a recess  50  into which the arm  17  may fit when the flapper valve gate  16  is in the open position, allowing the flapper valve gate  16  to lie substantially vertically to minimize inhibition of fluid movement from the middle portion  12  to the upper portion  11 . 
         [0028]    The arm  17  may be connected to a stem  18 , which may be substantially perpendicular to the arm  17 , via a connector portion  19 . The connector portion  19  of the arm  17  may run along the same axis as the stem  18  and may have an internal bore into which the stem  18  may fit. The stem  18  may be more clearly seen in  FIGS. 3A and 3B , which show a portion of the horizontal production tree  1  rotated  90  degrees from  FIGS. 1 ,  2 A, and  2 B.  FIG. 3A  shows the flapper valve gate  16  in the closed position, while  FIG. 3B  shows the flapper valve gate  16  in the open position. 
         [0029]    The stem  18  may be formed from two parts: a lower stem  20  and an upper stem  21 . The structure of the stem  18  may be more clearly seen in  FIGS. 4 and 5 . The connector portion  19  of the arm  17  may be secured to the upper stem  21  via one or more keys  25 , which each fit within a slot  27  running latterly along the exterior of the upper stem  21 , and one or more set screws  26 . The upper stem  21  may terminate in an externally threaded end  22 , which screws into an internally threaded end  23  of the lower stem  20 . The upper stem  21  and the lower stem  20  may then be secured to each other via a set screw  24 . 
         [0030]    The end of the lower stem  20  opposite the internally threaded end  23  may be rotatably secured within a recess  28  in the wall of the middle portion  12  of the body bore  5 . The lower stem  20  may have a bearing race assembly  29  integral to the lower stem  20 , and additional bearing race assemblies  30  and thrust bearings  31  may be placed on the lower stem  20  adjacent the bearing race assembly  29 . 
         [0031]    The end of the upper stem  21  opposite the externally threaded end  22  may extend through a channel  32  in the wall of the middle portion  12  of the body bore  5  and terminate outside the body  4  of the horizontal production tree  1  in a flapper valve bonnet assembly  33 . The flapper valve bonnet assembly  33  may comprise a flapper valve bonnet  34 , which may be secured to the exterior of the body  4  via a plurality of nut and stud assemblies  35 . The upper stem  21  may extend through an internal bore  36  in the flapper valve bonnet  34  and attach at its terminal end to a stem adapter  37  via a shear pin  38  extending through a hole  39  in the upper stem  21 . A hand wheel  40  is attached to the stem adapter  37 , whereby the hand wheel  40  can be turned to turn the stem adapter  37  and the stem  18  and, resultantly, pivot the flapper valve gate  16  between the open and closed positions. 
         [0032]    A valve packing elastomer set may attach to the flapper valve bonnet  34  and also surround the upper stem  21 . The valve packing is held in place by a packing retainer  45 . A bearing cap  41  may surround a portion of the flapper valve bonnet  34 , a portion of the packing retainer  45  and a portion of the stem adapter  37  such that the bearing cap  41  bridges the gaps between those elements. A first locking flange  42  may be attached to the bearing cap  41 . The first locking flange  42  may have a plurality of holes located around its perimeter. A second locking flange  43  may be attached to the hand wheel  40  such that the second locking flange  43  abuts the first locking flange  42  when the flapper valve bonnet assembly  33  is fully assembled. The second locking flange  43  may have a plurality of holes located around its perimeter such that the holes in the second locking flange  43  may align with the holes in the first locking flange  42 . A locking pin  44  may be attached to the hand wheel  40  via a connector  46  such that the locking pin  44  may be inserted through one of the holes in the first locking flange  42  and a corresponding hole in the second locking flange  43  to prevent the hand wheel  40  from turning, thus maintaining the flapper valve gate  16  in a particular position. 
         [0033]    The horizontal production tree can be installed on a well and stay in place for the life of the well. The well operator can frac the well through the horizontal tree by using an isolation sleeve to get into the tree. This will allow the tree to be safeguarded from frac propellant and frac pressures. Keeping the production tree on the well saves the cost of having a service company remove and reinstall the production tree. Using the isolation sleeve in the tree saves cost on purchasing larger equipment to handle frac pressures. The operator can also run production tubing through and pull tubing out of the well with the horizontal production tree still on the well. The tubing can be run under pressure and removed with the tree on the well. There is no need to remove the horizontal production tree on workovers. BOPs and frac valves can be flanged up to the tree. Two mechanical barriers can be set within the horizontal tree if a lubricator is needed to change out equipment above the tree. The unique tubing hanger design of the horizontal production tree allows ease of entry into the tubing bore. 
         [0034]    The horizontal production tree features a compact design. In field repairs can therefore be made without the need to climb on the equipment. Oil and gas operators may prefer the horizontal production tree in urban environments as its compact design allows for easy concealment from public view. The horizontal production tree can also be used in fields where the land owner uses irrigation sprayers, where height is an issue. 
         [0035]    Whereas, the devices and methods have been described in relation to the drawings and claims, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.