Abstract:
Embodiments of keyseat wipers for use in drilling processes, as well as methods for making and using such keyseat wipers, are described herein. Embodiments of keyseat wipers can include changing cross-sections and a relief sections that permit cut materials to pass by the keyseat wipers, reducing the possibility of a drill string with keyseat wipers from binding in a curved hole when being retrieved.

Description:
PRIORITY 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/562,272 filed on Nov. 21, 2011, entitled KEYSEAT WIPER, which is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    This application relates generally to tools for drill strings and methods of making and using such tools. In particular, this application relates to keyseat wipers for use with drill rods that are used in exploratory and production drilling, as well as methods for making and using such keyseat wipers. 
       BACKGROUND 
       [0003]    In a conventional process used in drilling, an open-faced drill bit is attached to a drill string, which is a series of connected 
       BACKGROUND 
       [0004]    In a conventional process used in drilling, an open-faced drill bit is attached to a drill string, which is a series of connected drill rods and tools that are assembled section by section as the drill string moves deeper into a formation during a drilling operation. During drilling operations, the drill string sometimes deviates from directly vertical, making at slightly arced path through the formation being drilled. In such cases, withdrawing a drill string from the borehole can be problematic as the drill string can bind against the curved wall of the bore hole. In particular, the pipe connections of the drill string, being wider at the connections than the pipe lengths, tends to dig into the side wall of the borehole creating what is known as a keyseat. 
         [0005]    In addition to the keyseats, attempts to work the drill string lose can case the borehole to deform and even collapse, causing additional problems with the drilling. In extreme circumstances, portions of the drill string may be damaged or destroyed while being withdrawn from the borehole. 
         [0006]    Some prior art has identified this problem and have provided keyseat reamers that encourage the drill string to exit the borehole without binding against the inner walls by cutting the keyseat to the width of the pipe connections. U.S. Pat. No. 4,330,043 includes a detailed description of the problem caused by keyseat formation and proposes a solution. However, the solution of the &#39;043 patent suffers from cut materials collecting in the flutes and binding the tool in the borehole as the excess cut materials have no way of passing by the keyseat wiper or being removed. 
       SUMMARY 
       [0007]    Embodiments of keyseat wipers for use in drilling processes, as well as methods for making and using such keyseat wipers, are described herein. Embodiments of keyseat wipers can include changing cross-sections and a relief sections that permit cut materials to pass by the keyseat wipers, reducing the possibility of a drill string with keyseat wipers from binding in a curved hole when being retrieved. 
         [0008]    In some embodiments, a keyseat wiper for placement in a drill string may include a first tapered section tapering from a first diameter to a second larger diameter; a wiper section having the second larger diameter; a second tapered section tapering from the second larger diameter to the first diameter; and a reduced section in the wiper section, the reduced section having a diameter smaller than the second larger diameter. In other embodiments, the first tapered section and the second tapered section may each include flutes, the flutes of the first tapered section being rotationally offset from the flutes of the second tapered section. In other embodiments, the keyseat wiper may further include at least one outside reduced section located adjacent to the first diameter of the first tapered section 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The following description can be better understood in light of Figures, in which: 
           [0010]      FIG. 1  illustrates an exemplary, side view of a keyseat wiper tool; 
           [0011]      FIG. 2  illustrates a cross-sectional view of a section of an exemplary keyseat wiper tool; 
           [0012]      FIG. 3  illustrates a cross-sectional view of a section of an exemplary keyseat wiper tool; 
           [0013]      FIG. 4  illustrates a cross-sectional view of a section of an exemplary keyseat wiper tool; 
           [0014]      FIG. 5  illustrates a cross-sectional view of a section of an exemplary keyseat wiper tool; 
           [0015]      FIG. 6  illustrates a cross-sectional view of a section of an exemplary keyseat wiper tool; and 
           [0016]      FIG. 7  illustrates a cross-sectional view of a section of an exemplary keyseat wiper tool. 
       
    
    
       [0017]    Together with the following description, the Figures demonstrate and explain the principles of the keyseat wiper tools and methods for using the keyseat wiper tools. In the Figures, the thickness and configuration of components may be exaggerated for clarity. The same reference numerals in different Figures represent the same component. 
       DETAILED DESCRIPTION 
       [0018]    The following description supplies specific details in order to provide a thorough understanding. 
         [0019]    Nevertheless, the skilled artisan would understand that the apparatus and associated methods of using the apparatus can be implemented and used without employing these specific details. Indeed, the apparatus and associated methods can be placed into practice by modifying the illustrated apparatus and associated methods and can be used in conjunction with any other apparatus and techniques conventionally used in the industry. For example, while the description below includes examples of rotary drilling, the apparatus and associated methods could be equally applied in other drilling process, such as core drilling, percussive drilling, and exploratory drilling, as well as other drilling procedures and systems. Indeed, the apparatus and associated methods could be used in any type of drilling process where a drill string may alter to a curved or arced borehole. And the term “drill rod” will be taken to include all forms of elongate members used in the drilling, installation and maintenance of bore holes and wells in the ground and will include rods, pipes, tubes and casings which are provided in lengths and are interconnected to be used in a borehole. 
         [0020]    The drill string keyseat wiper tools described in this application can have any configuration consistent with their operation described herein. One exemplary configuration of a keyseat wiper tool is illustrated in the Figures. The keyseat wiper tool is designed such that different cross sectional configurations cut and create passageways for a drill string to be withdrawn from an arced borehole. In some embodiments, relief sections may be provided with a narrower cross-sectional thickness to permit material cut by the keyseat wiper tool to aggregate and then fall past the relief sections down the borehole, solving the problems of conventional keyseat wipers. 
         [0021]    Different cutting sections are illustrated in the Figures. It should be understood that the different cross sectional views may transition into each other. As can be seen, different ends of the cutting section between sections B and F may be generally symmetric. For example, cross section B may be similar to F, cross section A may be similar to cross section E, and cross section C may be similar to cross section D. The similar cross sections, however, may be rotated with respect to each other to allow cut materials to pass to the bottom of the borehole. For example, in the Figures, the features of cross section B are rotated by 45 degrees with respect to the similar features of cross section F. 
         [0022]    The transition between cross sections B and A, and F and E, may be tapered to provide a sloped engagement to reduce the amount of cutting that the keyseat wiper would have to perform. The taper alone may help force the drill string into the correct alignment with the borehole in harder substrate materials, reducing the amount of time and energy required to withdraw the drill string from the borehole. Thus, cross sections C and D have a larger diameter than cross sections B and F. 
         [0023]    As shown in the Figures, the tapered sections between cross section B and A and between cross sections F and E include multiple cutting teeth to remove materials from the sidewall. Cross sections C and D include flutes to permit cut material to move along the keyseat wiper. Because of the rotated features, the flutes of cross sections C and D may be deeper since an extended portion of cross sections C or D would always be in contact with the side wall of the borehole. 
         [0024]    The diameter of cross sections D and C may be about the same as the diameter of the borehole. When the diameter of cross sections D and C are about the same as the diameter of the borehole, the keyseat wiper tool may serve to effectively guide the drill string out of the borehole without unnecessary cutting by the keyseat wiper. 
         [0025]    A reduced portion may be provided on one or both ends of the tool outside of the tapered section between cross sections B and F. The reduced portion may help cut materials to pass by the tool. Similarly, between cross sections D and C, a reduced section may be included that allows cut materials collecting in the flutes of cross sections D and C to loosen and pass along the tool, thus overcoming the problems of compacted cut materials that tend to bind prior art reamers and keyseat wipers. 
         [0026]    Various surfaces of the different features of the illustrated cross sections may include an abrasive coating, or may be formed from a material for cutting (such as cut-rite) for assisting in cutting the materials away from the keyseat. Similarly, in some embodiments, As shown in  FIG. 4 , the extended portions of the flutes in cross sections D and C may be replaceable through a variety of known methods of replacing tool parts. 
         [0027]    In addition to any previously indicated modification, numerous other variations and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of this description, and any claims are intended to cover such modifications and arrangements. Thus, while the information has been described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred aspects, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, form, function, manner of operation and use may be made without departing from the principles and concepts set forth herein. Also, as used herein, examples are meant to be illustrative only and should not be construed to be limiting in any manner.