Abstract:
The invention comprises a downhole jet motor, and a method of using same, that can be utilized to drill or to clean a well bore or tubing. The jet motor comprises a power shaft partially surrounded by a control sleeve defining a blind annular space, closed at the upper end and open at the lower end to allow fluid discharge. At least one opening is provided in the drive shaft wall extending radially within the annulus region. Drilling or cleaning fluid pressure is directed to the at least one opening in the power shaft. The control sleeve provides a reaction structure in relation to fluid discharged from the at least one opening producing rotation of the drive shaft in relation to the control sleeve.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 60/787,906 entitled, “Downhole Tool,” filed on Mar. 31, 2006, in the United States Patent and Trademark Office. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to a downhole drilling and cleaning apparatus. More specifically, the invention is directed to a motor and apparatus for cleaning out production tubing, for drilling oil and gas wells and like applications. 
     2. Description of the Related Art 
     The use of hydraulically driven drill bits is known in the art as described in the following U.S. patents. 
     U.S. Pat. No. 1,727,276, issued to Diehl on Sep. 3, 1929, discloses a drill bit rotating at one speed and a body portion rotating at a second lower speed. Once the drill bit engages a hard formation the drill bit and the body combine and rotate at the speed of the body portion. 
     U.S. Pat. No. 1,860,214, issued to Yeaman on May 24, 1932, discloses a hydraulically rotating drill bit with exhaust passages through the bit body for the escape of impelling fluid. 
     U.S. Pat. No. 3,133,603, issued to Lagacherie, et al on May 19, 1964, discloses a fluid driven-bit wherein fluid passes over an internal turbine. The fluid acts upon the internal turbine in order to rotate the drill bit. 
     U.S. Pat. No. 3,844,362, issued to Elbert, et al on Oct. 29, 1974, discloses a device for boring holes comprising a body having a front end and a rear end wherein forward drive means are provided at the rear end for receiving pressurized fluid. A boring head is rotatably mounted in the body and projects from the front end of the body. Passages direct fluid from the boring head to impart torque to the boring head. 
     U.S. Pat. Nos. 4,440,242 and 4,529,046, issued to Schmidt, et al on Apr. 3, 1984 and Jul. 16, 1985 respectively, disclose a drilling apparatus having nozzles functioning as cutting jets and passages discharging radially to generate torque for rotation. 
     U.S. Pat. No. 5,101,916, issued to Lesh for on Apr. 7, 1992, discloses a fluid-driven tool wherein pressurized fluid is used to create rotation by force applied to internal helical vanes. 
     U.S. Pat. No. 5,385,407, issued to De Lucia on Jan. 31, 1995, discloses a tool having three sections wherein lubricant is permitted to flow through orifices to lubricate the bearing assembly. 
     U.S. Pat. No. 6,520,271, issued to Martini on Feb. 18, 2003, discloses a fluid-driven tool wherein pressurized fluid is used to create rotation by internal vanes. 
     The prior art does not disclose a downhole motor capable of generating rotational and thrust torque with radially-extending nozzles in cooperation with a control sleeve. 
     The prior art does not disclose a downhole motor capable of generating significant torque utilizing a fluid comprising either a liquid or a gas. 
     It is a further object of the present invention to provide a downhole drilling and cleaning tool having a plurality of nozzles providing rotational and forward thrust in cooperation with a control sleeve. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention comprises a jet motor downhole tool that can be utilized to drill or to clean a well bore or tubing associated therewith. The jet motor includes a motor comprising drive nozzles at a power shaft generating rotational torque acting in cooperation with a control sleeve. The jet motor connects to an upper member that is in fluid communication with the source of drilling or cleaning fluid. Drilling or cleaning fluid pressure is directed to nozzles in the power shaft extending generally in a radial direction. The nozzles may be oriented at an axial angle obtusely to provide downward force. The power shaft rotates in relation to a control sleeve spaced from the power shaft, the control sleeve providing a reaction structure in relation to fluid discharged from the nozzles. The control sleeve and the power shaft define a blind annular space, closed at the upper end and open at the lower end to allow fluid discharge. 
     Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of the jet motor as fully assembled. 
         FIG. 2  is a partial exploded view of the jet motor. 
         FIG. 3A  is a perspective view of the drill bit of the jet motor. 
         FIG. 3B  is a perspective view of an alternative embodiment of the drill bit. 
         FIG. 3C  is a cross-sectional view of the power shaft of the jet motor taken along plane  3 C in  FIG. 2 . 
         FIG. 4  is a cross-sectional view of the jet motor taken along axis A-A in  FIG. 1  and through the drive nozzles. 
         FIG. 4A  is a cross-sectional view of the drill bit taken along line  4 A- 4 A in  FIG. 4 . 
         FIG. 4B  is a cross-sectional view of an alternative embodiment of the drill bit taken through the nozzles. 
         FIG. 5  is a cross-sectional view of an alternative embodiment of the jet motor. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , the exterior of the present invention  10  generally comprises a drill bit  20 , control sleeve  12 , and upper subassembly  16  having a common central longitudinal axis AA. 
     As used herein, “upper” will refer to the direction of upper end  80  of upper subassembly  16  that connects to a drill string or tubing (not shown). As used herein, “lower” will refer to the direction of the drill face  18  of drill bit  20 . 
     Referring to  FIG. 2 , drill bit  20  is generally a closed cylindrical structure with an open connection end  24 . Channel  22  extends inwardly of bit  20  from connection end  24 . In an exemplary embodiment, threading is provided on the interior surface of drill bit  20  proximate connection end  24  for threaded connection to threaded lower connector  23  of power shaft assembly  36 . 
     In an exemplary embodiment, drill bit face  18  is textured to model a rock configuration as depicted in  FIG. 3A . Alternatively, drill bit face  18  is comprised of a plurality of nodes, as seen in  FIG. 3B . 
     At least one rotation nozzle  26  is disposed in cylinder wall  27  of drill bit  20 . In an exemplary embodiment at least two rotation nozzles  26  are provided. Rotation nozzles  26  are in fluid communication with the interior channel  22  of drill bit  20  and allow fluid flow from channel  22  to the exterior of bit  20 . 
     Referring to  FIG. 4A , nozzles  26  each have an axis NN. Axes NN are each disposed generally perpendicularly to axis AA. Axes NN of the rotation nozzles  26  are each oriented radially to allow fluid expulsion from nozzles  26  to provide rotational thrust in a desired direction. Specifically, the angle N′ of each axis NN with respect to a plane passing through axis AA and interior opening  29  of cylinder wall  27  is acute in the preferred direction of rotation. 
     Referring to  FIG. 4B , in an alternative embodiment, nozzles  26  may each be oriented from a plane normal to axis AA at the interior opening  29  of each nozzle  26  to provide a forward thrust from fluid escaping through nozzles  26 . 
     Referring to  FIGS. 2 ,  3  and  4 , cutting nozzles  28  are provided in bit face  18 . Cutting nozzles  28  are in fluid communication with interior channel  22  of drill bit  20 . The axes of cutting nozzles  28  may be oriented parallel with axis AA or at an angle to axis AA. Fluid escaping from nozzles  28  provides cutting forces and washes loose materials away from bit face  18 . 
     Control sleeve  12  is generally composed of an elongated cylindrical barrel body, with a sleeve channel  17  passing therethrough. Sleeve channel  17  is oriented along axis AA. 
     Referring to  FIG. 4 . control sleeve  12  is provided with threading  19  at its upper end  32  for threaded connection to threaded lower end  42  of upper subassembly  16 . Upper subassembly  16  is provided with threading  82  at its end  80  to allow connection to a drill string or tubing (not shown). Such threaded connections are commonly practiced. Accordingly, control sleeve  12 , after installation on a drill string or tubing, is in a fixed position in relation to the drill string or tubing. 
     Referring to  FIGS. 2 and 4 , power shaft assembly  36  is depicted. Power shaft assembly  36  includes power shaft  30 , lower radial bearing  46 , thrust bushing  48 , upper radial bearing  44 , retainer  38  and upper thrust bushing  70 . 
     Power shaft  30  comprises a hollow cylinder structure having an internal channel  66  aligned with axis AA. Internal channel  66  allows fluid communication from a drill string or tube (not shown) to channel  22  of drill bit  20 . 
     Power shaft  30  is constructed and sized to rotate within control sleeve  12  with lower radial bearing  46  and upper radial bearing  44  providing radial support. As drill bit  20  is fixedly attached to power shaft  30 , drill bit  20  and power shaft  30  rotate together in relation to control sleeve  12 . 
     Thrust bushing  48  extends intermediate lower radial bearing  46  and upper radial bearing  44 . 
     A retainer nut  38  is provided on power shaft  30  intermediate upper radial bearing  44  and upper end  60  of power shaft  30 . Retainer nut  38  is provided with an internal threading  39  to attach to corresponding threading  81  provided on power shaft  30  to retain radial bearings  44  and  46  and thrust bushing  48  intermediate retainer nut  38  and a shoulder  69  on power shaft  30  and shoulder  68  on control sleeve  12 , as seen in  FIG. 4  (upper portion). 
     Power shaft  30 , control sleeve  12 , shoulder  68  and end  56  of lower radial bearing  46  define a blind annular space  55  intermediate exterior surface  33  of power shaft  30  and inner surface  34  of control sleeve  12 , blind annular space  55  having an upper end  45  defined by end  56  of lower radial bearing  46  and shoulder  68  of control sleeve  12 . 
     In an alternative embodiment, an annular seal (not shown) may be provided at end  56  of lower radial bearing  46  to define the upper end  45  of annular space  55 . An annular opening  54  of annular space  55  is defined intermediate control sleeve  12  and power shaft  30 . 
     At least one drive nozzle  52  extends through wall  31  of power shaft  30 . In an exemplary embodiment, at least two drive nozzles  52  are provided spaced within wall  31  of power shaft  30 . Drive nozzles  52  are in fluid communication with the internal channel  66  of power shaft  30 . 
     Drive nozzles  52  are located intermediate annular opening  54  of annular space  55  and upper end  45  of annular space  55 . Drive nozzles  52  allow fluid flow from channel  66  to annular space  55 . 
     Drive nozzles  52  each have an axis DD, as seen in  FIG. 3C . Axes DD are each oriented angularly with respect to axis AA, the angle being acute in the direction of upper end  60  of power shaft  30  and obtuse with respect to the direction of the threaded lower connector  23 . Accordingly, drive nozzles  52  are each oriented rearward from a plane normal to axis AA at the interior opening  57  of each nozzle  52 . Such orientation provides a forward thrust from fluid escaping through nozzles  52 . 
     Referring to  FIG. 3C , axes DD of the drive nozzles  52  are each angled radially to allow fluid expulsion from nozzles  52  to provide rotational thrust in a desired direction. Specifically, the angle D′ of each axis DD with respect to a plane passing through axis AA and shaft wall  31  at interior opening  57  is acute in relation to the plane. 
     In the exemplary embodiment shown, rotation nozzles  26  and drive nozzles  52  are depicted. In an alternative embodiment, not shown, ports may be provided without nozzles to achieve the results of the invention. The principles taught in this invention apply with ports used in lieu of rotation nozzles  26  or drive nozzles  52 . 
     Inner surface  34  of control sleeve  12  is spaced from exterior surface  33  of power shaft  30 . The extent of separation is gap  49 . In operation, fluid forced through internal channel  66  is expelled through drive nozzles  52 . Upon impinging inner surface  34 , a reactive force is incurred, thereby enhancing the rotation of power shaft  30 . 
     In an exemplary embodiment, gap  49  is in the range of 0.0381 cm to 0.0762 cm (0.015″ to 0.030″) for a tool having a nominal diameter in the range of 3.175 cm to 4.445 cm (1.25″ to 1.75″). In an exemplary embodiment, gap  49  is in the range of 0.508 cm to 0.635 cm (0.20″ to 0.25″) for a tool having a nominal diameter in the range of 10.4775 cm to 12.065 cm (4.125″ to 4.75″). Generally, gap  49  is effective in a range of ratios of gap  49  to nominal diameter of the control sleeve  12  (gap:sleeve diameter) as follows: Ratio of 1:125 to ratio of 1:17. Depending on various application requirements, including the fluid used, nozzle size, pressure and other factors, ratios outside the foregoing range may be preferred. 
     Referring to  FIGS. 2 and 4 , upper subassembly  16  comprises a generally hollow cylindrical body  61  having a connecting threading  82  for connecting to a drill string or tubing (not shown) at its upper end  80 , and connecting threading threaded lower end  42  for connecting to control sleeve  12  at control sleeve threading  19 . Upper subassembly  16  includes an interior channel  72  aligned with axis AA. 
     An injection tube  96  is provided in upper subassembly  16 . Injection tube  96  includes an elongated tube  40  and tube head  41 . Tube head  41  has a larger diameter than tube  40 . A tube retaining nut  86  is provided to retain tube head  41  between retaining nut  86  and a shoulder  87  provided in upper subassembly  16 . Retaining nut  86 , tube head  41  and tube  40  define a continuous tube channel  95  aligned with axis AA. Retaining nut  86  has connecting threading  84  for threaded connection to internal connecting threading  83  provided in upper subassembly  16 . 
     In an exemplary embodiment, injection tube  96  is retained in position by the retaining nut  86  and shoulder  87 . Injection tube  96  is free to rotate about axis AA independent of the rotation of power shaft  30  and upper subassembly  16 . 
     Upper subassembly  16  is provided with a cylindrical inset  88  at its lower end  62 . A thrust bushing  70  is provided to provide a bearing surface intermediate upper subassembly  16  and power shaft assembly  36 . Thrust bushing  70  additionally encloses and provides radial support for tube  40 . 
     Tube  40  extends past the lower end  62  of upper subassembly  16  into the channel  66  of power shaft  30 . 
     The interior surface  71  of thrust bushing  70  is sized and constructed to encircle the exterior surface  43  of tube  40  but to allow rotation between the surfaces. Thrust bushing  70  further contains a flange  74  extending radially outward. Flange  74  is received between the lower end  62  of upper subassembly  16  and upper end  60  of power shaft  30 . Thrust bushing  70  includes a cylindrical inset  78  to receive a segment of power shaft  30  at the upper end  60  of power shaft  30 . Cylindrical inset  78  is sized and constructed to slidably receive end  60  of power shaft  30 . 
     The diameter of outer surface  43  of injection tube  96  is preferably only slightly smaller than the diameter of channel  66  allowing injection tube  96  to be slidably received in channel  66 . 
     In an exemplary embodiment of the present invention, the injection tube  96  with a tube wall  90  having a width such that the wall will expand slightly when an appropriate operating pressure is applied internal of wall  90  in tube channel  95 . Such slight expansion creates a seal between the exterior surface  43  of tube wall  90  and the interior surface  93  of power shaft  30  that defines channel  66 . 
     In an exemplary embodiment, the tube wall  90  is provided with a slight flare proximate its lower end  64  to enhance sealing of tube wall  90  and the interior surface  93 . A preferred flare angle is up to five degrees outwardly from the tube wall segment that is not flared. 
     In summary, the power shaft assembly  36  is fixedly attached to the drill bit  20 . Power shaft assembly  36  is rotatable within control sleeve  12 . A blind annular space  55  is defined between power shaft  30  and control sleeve  12 . 
     In operation, jet motor  10  of the present invention is attached to a drill string or tube (not shown). A fluid (drilling fluid or gas) is introduced into the drill string or tube at determined pressures. Pressure is applied to the fluid forcing the fluid through aligned channels  72 ,  95 ,  66  and  22 . The fluid is forced through drive nozzles  52 , rotation nozzles  26  and cutting nozzles  28 . The pressure from the fluid in channels  66  and  22  is greater than the ambient downhole pressure. Differential pressure at rotation nozzles  26  and drive nozzles  52  create rotational torque on the drill bit  20  and power shaft  30 . 
     Importantly, the proximity of inner surface  34  of control sleeve  12  provides a surface that is stationary relative to power shaft  30 . The expansive force of the fluid escaping drive nozzles  52  impinging surface  34  enhances the rotational torque on power shaft  30 . 
     Gap  49  may be determined to provide desired reactive force of fluid expelled through drive nozzles  52  at inner surface  34 . In addition, the force of the drilling fluid may be manipulated in order to control the thrust of the drilling fluid against the sleeve inner surface  34  through the drive nozzle  52  thereby controlling the rotation of the power shaft  30  and the drill bit  20 . 
     As the drive nozzles  52  are located intermediate opening  54  of annular space  55  and upper end  45 , fluid forced out of drive nozzles  52  is forced out of opening  54 , thereby continually washing annular space  55  and preventing accumulation of debris in annular space  55 . 
       FIG. 5  depicts an alternative exemplary embodiment wherein four drive nozzles  52  are located on power shaft  30  in order to increase the amount of fluid expelled through the drive nozzles  52 . Drive nozzles  52  are depicted as symmetrically situated opposing pairs with respect to each other. Drive nozzles  52  may also be situated asymmetrically or in any combination of the two. 
     In an exemplary embodiment, an appropriate gas, such as nitrogen, may be utilized as the fluid medium. The construction of the present invention, particularly the construction of injection tube wall  90  with expansion capability upon application of appropriate fluid pressure in tube channel  95  together with fit of exterior surface  43  of tube wall  90  and the interior surface  93  of power shaft  30  allows the creation of an effective seal even though the fluid is a gas. 
     The exemplary embodiment providing a flared lower end  64  of tube wall  90  provides an effective seal at interior surface  93  as internal fluid pressure is applied at the open end of lower end  64 . 
     The foregoing description of the invention illustrates a preferred embodiment thereof. Various changes may be made in the details of the illustrated construction within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the claims and their equivalents.