Abstract:
A well cap rod hanger for securing a well head having an upper portion adapted to be attached to a rod elevator, a body having a lower cylindrical portion with a threaded outer surface adapted to be threadedly attached to the inside diameter of a well head, and a second cylindrical portion extending downward from the body, the second cylindrical portion adapted to be threadedly attached to a rod string.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to the servicing and sealing of oil or gas wells. More particularly, the present invention relates to well caps for attachment to a well head. 
       BACKGROUND OF THE INVENTION 
       [0002]    An oil or gas well can be secured (to maintain well control) by having a stuffing box attached to the well head. A series of interconnected rods, the rod string, begins at the well head and extends down to either connect to the oil pump, which lies below the earth&#39;s surface where the hydrocarbon-bearing formation is found, or to reach the gas reservoir. Attached to the top of the uppermost rod is a polished rod, which runs through the stuffing box. The smooth surface of the polished rod allows efficient hydraulic seals to be formed around the reciprocating or rotating rod string. 
         [0003]    When servicing the well, the stuffing box and polished rod are removed to allow access to the rod string. Rods may be removed to service the well and its components. While the stuffing box and polished rod are removed from the rod string, rod elevators support the weight of the rod string. A rod elevator is a lightweight elevator designed for running and retrieving the rod string in wells equipped with a rod pump. Rod elevators can be used on a service rig or a rod unit specifically designed for running and retrieving rod strings. The elevator is not designed to secure the well head if the well was to become pressurized. 
         [0004]    Radigans may or may not be present on the well head. A radigan is a semi-circular rubber clamp seated inside the well head. The radigans can be closed to prevent a blow out if the well pressure rises quickly and function by closing around a rod to close the hole. Thus, radigans may be used to secure a well head only if there are rods running through the well head, and if pressure in the well quickly rises (which may lead to a blow out), the polished rod and stuffing box must be quickly attached to the well head before the well can be secured. Even once the polished rod and stuffing box are in place, closing the radigans takes several minutes. The usefulness of using radigans to secure the well is further limited in that radigans will not permanently secure the well, the radigans must be built to a size that is compatible with a given rod string to secure a well to the extent that they can, and radigans cannot support the weight of the rod string. 
         [0005]    The stuffing box and polished rod must be attached to the rod string using rod elevators. This process can take several minutes because the stuffing box and polished rod are heavy (can weigh 136 kg/300 lb) and extremely difficult to handle (9 m/30 ft long). The current techniques to temporarily secure the stuffing box and polished rod to the well head and rod string, to secure the well, can be dangerous when working under pressure. Often, the stuffing box and polished rod need to be quickly attached to the well head and rod string to secure the well. A quick change in weather conditions (rain, hail, lightning, high winds, etc.) can make working conditions dangerous, thus securing the well quickly and safely becomes extremely important. Thus, hydrocarbon spills during a blow out can often only be controlled as quickly as the workers can attach the stuffing box and polished rod to the well head and rod string. 
         [0006]    A well cap is a is a threaded piece of steel that attaches to the well head to secure the well. Previous well caps cannot be used to secure a well head while rods are present in the well. 
         [0007]    U.S. Pat. No. 4,467,871 issued to Rollwitz teaches a clamp-based rod stand that attaches to a polished rod by encirclement and holds it above the well head, thus freeing up the pumpjack. The invention taught by Rollwitz does not assist in securing the well. 
         [0008]    U.S. Pat. No. 4,850,736 issued to Petrie teaches a rod clamp that facilitates servicing of an oil well, reduces the likelihood of a rod string falling into the inground portion of the well, and minimizes scarring of polished rods by eliminating the need to reposition. The invention taught by Petrie does not assist in securing the well. 
         [0009]    Given the difficulty, danger, and wastage experienced while securing a well head with a stuffing box and rod string, it is desirable to provide a device to facilitate the servicing and securing of a well or rod string. 
       SUMMARY OF THE INVENTION 
       [0010]    It is an object of the present invention to obviate or mitigate at least one disadvantage of previous method and apparatus for temporarily securing a rod string and well head. 
         [0011]    In a first aspect, the present invention provides a well cap rod hanger for securing a well head having an upper portion adapted to be attached to a rod elevator, a body having a lower cylindrical portion with a threaded outer surface adapted to be threadedly attached to the inside diameter of a well head, and a second cylindrical portion extending downward from the body, the second cylindrical portion adapted to be threadedly attached to a downhole implement. 
         [0012]    In one embodiment, the upper portion including a head and a neck, the head having a greater outer dimension than the neck, and a tapered portion between the head and the neck. 
         [0013]    In one embodiment, the well cap rod hanger further includes a tapered portion between the head and the neck. 
         [0014]    In one embodiment, the downhole implement includes a rod string. In one embodiment, the downhole implement includes a measuring device. In one embodiment, the measuring device includes a down hole recorder. 
         [0015]    In a further aspect, the present invention provides a method of securing a well having a well head, including providing a well cap rod hanger having an upper portion adapted to be attached to a rod elevator, a body having a lower cylindrical portion with a threaded outer surface adapted to be threadedly attached to the inside diameter of a well head, and a second cylindrical portion extending downward from the body, the second cylindrical portion adapted to be threadedly attached to a rod string, connecting the rod string and the second cylindrical portion, and connecting the lower cylindrical portion to the well head, wherein the well head is secured with the rod string within the well. 
         [0016]    In one embodiment, a fluid tight seal is formed between the lower cylindrical portion and the well head. 
         [0017]    In one embodiment, the method includes lowering the rod string and the well cap rod hanger using the elevator until the lower cylindrical portion is at the well head. 
         [0018]    In a further aspect, the present invention provides a well cap rod hanger for securing a well head having an upper portion, having a head and neck, the upper portion adapted to be attached to a rod elevator, a body having a gripping portion and a lower cylindrical portion, the lower cylindrical portion having a threaded outer surface adapted to be threadedly attached to the inside diameter of a well head, and a second cylindrical portion extending downward from the body, the second cylindrical portion adapted to be threadedly attached to a rod string. 
         [0019]    Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein: 
           [0021]      FIG. 1  is a schematic of a well cap rod hanger of the present invention; and 
           [0022]      FIG. 2  is a schematic of the well cap rod hanger of  FIG. 1  in use with a well head, a rod string, and a rod elevator. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Generally, the present invention provides a well cap rod hanger for temporarily securing a well head or well head and a rod string. Alternatively, a well head can be secured and a device intended to depend into the well, such as a measuring device, may be attached to the apparatus. 
         [0024]    Referring to  FIG. 1 , a well cap rod hanger  10  in accordance with the present invention includes a head  20 , a tapered shoulder  30 , and a neck  40 . The head  20 , a tapered shoulder  30 , and a neck  40  collectively comprise the upper portion  45 . The upper portion  45  is adapted to be attached to a rod elevator  100  ( FIG. 2 ) (or other lifting means, such as a crane or travelling block etc. known to one skilled in the art), preferably through grasping by the rod elevator, so that the rod elevator  100  may be used to support the rod string  90  and move the well cap rod hanger  10  up/down to move the rod string  90  in/out of the well. The tapered shoulder  30  is to hold a rod elevator  100 , the width of the neck  40  is narrow enough to be grasped by the rod elevator  100  and the length of the neck  40  is preferably equal to or greater than the grasp of the rod elevator  100 . The head  20  and the neck  40  are each preferably cylindrical in shape. 
         [0025]    The well cap rod hanger  10  also includes a tapered shoulder  50  and a body  60 , the body  60  having a threaded lower portion  65  adapted to be threadedly attached to the interior of a well head  80  ( FIG. 2 ). The tapered portion  50  is between the neck  40  and a body  60 . The body  60  is preferably cylindrical in shape. The tapered shoulder  50 , the body  60 , and the threaded lower portion  65  collectively comprise the lower portion  67 . The pin  70  has a threaded surface  75  adapted to be threadedly attached to the a rod string  90  ( FIG. 2 ). 
         [0026]    The upper portion  45  may be integral to the lower portion  67 , or the upper portion  45  and the lower portion  67  may be separate components adapted to be attached to each other. Similarly, the pin  70  may be integral to the lower portion  67 , or the pin  70  may and the lower portion  67  may be separate components adapted to be attached to each other. 
         [0027]    The upper portion  45  may be any type of contact point that can be securely grasped by the rod elevator  100 . For example, rather than comprising the head  20 , tapered shoulder  30 , and neck  40 , or some combination of those components, the portion of the well cap rod hanger  10  above the lower portion  67  may be a hook, clevis, eye, or other attachment means known to one skilled in the art. 
         [0028]    Referring to  FIG. 2 , the well cap rod hanger  10  is depicted with the well head  80  and the rod string  90 . The rod elevator  100  grasps the upper portion  45  and the well cap rod hanger  10  is lowered into position such that the threaded lower portion  65  can be secured to the well head  80  and that the pin  70  can be secured to the rod string  90 . To secure the well cap rod hanger  10  to the well head  80  and to the rod string  90 , the threaded lower portion  65  is threadedly attached to the well head  80  and the pin  70  is threadedly attached to the rod string  90 . The threaded lower portion  65  and the pin  70  can be threadedly attached to the well head  80  and rod string  90 , respectively, through use of a pipe wrench, which may grip the preferably cylindrical body  60 , and the rod string  90 , respectively. The threaded lower portion  65  and threaded surface  75  are threaded in the same orientation, allowing them to be tightened or loosened in the same direction to threadedly attach the well cap rod hanger  10  to the well head  80  and rod string  90 . 
         [0029]    Alternatively, the pin  70  may be first threadedly attached to the rod string  90  while the well cap rod hanger  10  is grasped by the rod elevator  100  while the rod string is suspended above the well head  80 . The welt cap rod hanger  10  and rod string  90  are then lowered together by the rod elevator to allow the lower portion  65  to be threadedly attached to the well head  80 , forming a fluid seal. 
         [0030]    Once the pin  70  is threadedly attached to the rod string  90  and the threaded lower portion  65  is attached to the well head  80 , the rod elevator  100  can be released because the well cap rod hanger  10  is bearing the weight of the rod string  90 . The well cap rod hanger  10  also secures the well head  80  because it is threadedly sealingly attached to the well head  80 . 
         [0031]    To remove the well cap rod hanger  10 , the threaded lower portion  65  and the pin  70  are respectively disengaged from the well head  80  and from the rod string  90 . The well cap rod hanger  10  is then removed from the well head  80 . Removal of the well cap rod hanger  10  from the well head  80  is possible by using a pipe wrench to disengage the threaded lower portion  65  and the pin  70  from the well head  80  and the rod string  90 , respectively. 
         [0032]    The threaded portion lower portion  65  and pin  70  may be constructed with various diameters, the respective diameters being selected to create a well cap rod hanger  10  that is compatible with a given well head and rod string. 
         [0033]    In addition to sealing a well, the invention herein described may be used to suspend a rod string. When a well is abandoned or put off line, the typical practice is to back off the polished rod and let the rod string sit on the bottom of the well. In this case, the rod string will bend and the pump can seize. The invention herein described can be used to suspend the rods in the tubing so they can be used at a later date. A typical rod string and pump can cost up to $20,000. The invention herein described may also be used to suspend any downhole tool within a casing or production tubing. 
         [0034]    In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the invention. 
         [0035]    The above-described embodiments of the invention are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.