Abstract:
A system for producing wellbore fluids. The system includes a pumping system deployable into tubing disposed in a wellbore, the pumping system includes a pump, a pump motor, a reservoir for containing purging fluid, and conductors in electrical communication with the pump motor. Electrical supply contacts in the tubing are connected to a downhole electrical power supply via a power cable extending along the tubing length from the surface. The conductors are engageable with the electrical supply contacts when the pumping system is landed within the tubing. Purging fluid in the reservoir can be flowed between the conductors and the supply contacts to remove conductive fluid prior to engaging the conductors and supply contacts. The conductors are selectively extended from a retracted position in the pumping system.

Description:
BACKGROUND 
       [0001]    1. Field of Invention 
         [0002]    The present disclosure relates to downhole pumping systems submersible in well bore fluids. More specifically, the present disclosure concerns lowering a submersible pump system through tubing and connecting it electrically to an electrical receptacle mounted in the tubing. 
         [0003]    2. Description of Prior Art 
         [0004]    Submersible pumping systems are often used in hydrocarbon producing wells for pumping fluids from within the wellbore to the surface. These fluids are generally liquids and include produced liquid hydrocarbon as well as water. One type of system used in this application employs an electrical submersible pump (ESP). ESPs are typically disposed at the end of a length of production tubing and have an electrically powered motor. Often electrical power may be supplied to the pump motor via a power cable. Normally, the power cable is strapped to the tubing and lowered along with the pump and the tubing. Typically, the pumping unit is disposed within the well bore just above where perforations are made into a hydrocarbon producing zone. ESP&#39;s typically require periodic retrieval for scheduled maintenance or repair. This usually entails removing the tubing and the power cable, which is secured alongside the tubing. Pulling and re-running the tubing is time consuming and pulling and reusing the power cable creates mechanical wear and can sometimes damage the cable. 
         [0005]    Lowering the pumping assembly inside the production tubing would avoid a need for pulling the tubing to retrieve the pump. Proposals have been made to run the power cable on the tubing exterior and the pump in the tubing. The pump stacks into engagement with electrical contacts provided on the power cable lower end. 
       SUMMARY OF INVENTION 
       [0006]    The present disclosure includes a system for producing fluids from a hydrocarbon producing wellbore, the system comprises production tubing disposed within the wellbore, a pumping system having a pump with fluid inlets, and a pump motor mechanically coupled to the pump. The pumping system is deployable through the production tubing. A conductor shoe is affixed within the production tubing and configured to matingly couple with the pumping system. Also included is an electrical power supply line connected to a power source that connects with or otherwise engages a conductor shoe. Half of a conductor set may be included with the pumping system, where the conductors selectively extend outward as the pumping system couples with the conductor shoe. Optionally, conductors may be provided with the production tubing and selectively extend inward. The deployable pumping system can further include a supply of non-conducting fluid for purging the space where electrical connections are made. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]    Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
           [0008]      FIG. 1  is a side partial sectional view of a receptacle attached to production tubing. 
           [0009]      FIG. 2  is sectional view of the receptacle of  FIG. 1 . 
           [0010]      FIG. 3  is a detailed sectional view of a portion of the receptacle of  FIG. 1 . 
           [0011]      FIG. 4  is a sectional view of the receptacle of  FIG. 3 . 
           [0012]      FIGS. 5A-5C  are side section views of an assembly to be deployed in the production tubing and receptacle. 
           [0013]      FIGS. 6-8  are sectional views of the embodiments of  FIGS. 5A-5C . 
           [0014]      FIGS. 9A and 9B  are side partial sectional views of the assembly landing in the receptacle. 
           [0015]      FIGS. 10A and 10B  are side partial sectional views of the assembly landed in the receptacle. 
           [0016]      FIGS. 11 and 12  are sectional views respectively from  FIGS. 10A and 10B . 
           [0017]      FIG. 13  is a side partial sectional view of the assembly fully coupled with the receptacle in a wellbore. 
       
    
    
       [0018]    While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF INVENTION 
       [0019]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. For the convenience in referring to the accompanying figures, directional terms are used for reference and illustration only. For example, the directional terms such as “upper”, “lower”, “above”, “below”, and the like are being used to illustrate a relational location. 
         [0020]    It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, the invention is therefore to be limited only by the scope of the appended claims. 
         [0021]    An example of an annular receptacle assembly  55  is shown in partial cross sectional view in  FIG. 1  connected to the production tubing  54  lower end. Inlet passages  68  are shown formed through the receptacle assembly  55  near its upper end. Keys  63  are affixed to the receptacle assembly  55  inner circumference below the passages  68 . The keys  63  are elongate members that jut out into the assembly  55  annulus with their elongate side aligned with the assembly  55  axis. The receptacle assembly  55  inner diameter reduces at a transition  57  shown below the keys  63 . A conductor assembly  56  (also referred to herein as a conductor shoe) is shown provided on the receptacle assembly  55  lower end. The examples of the conductor assembly  56  depicted includes an annular upper member  65  and a lower member  67 . The upper member  65  upper end is coaxially affixed around the receptacle assembly  55  lower end. The upper member  65  lower end connects to the lower member  67 . 
         [0022]    An upper polished bore (PBR)  58  is shown formed within the upper member  65  annulus and extending into the lower member  67  inner surface. The upper PBR  58  transitions to a smaller diameter within the lower member  67 , thereby defining a lower PBR  60 . The upper and lower PBRs  58 ,  60  may be polished to provide sealing surfaces. Bore  61  coaxially extends downward from the lower PBR  60  through the lower member  67 , the  61  is shown having a diameter less than the lower PBR  60  diameter. 
         [0023]    An electrical cable  66  is provided adjacent the receptacle assembly  55 . The electrical cable  66  connects on upper end to an electrical power source (not shown) terminating at a compression fitting  69  anchored onto the upper member  65 . A detail is illustrated in  FIG. 3  depicting an example of cable  66  connections to distribute power within the assembly  55 . As shown, the cable  66  extends into a passage  72  formed in the upper member  65  and parallel to its axis. The passage  72  intersects an annular cavity  74  formed through the upper member  65  circumference. Supply leads  64  extend from the cable  66  into the cavity  74 . 
         [0024]      FIGS. 1 and 3  include an example of electrically distributing the power from the cable  66  within the receptacle assembly  55 . Shown is an annular sleeve retainer  76  is coaxially provided within the upper member  65 . The sleeve retainer  76  adjoins the lower member  67  and the upper PBR  58  extends onto the sleeve retainer  76  inner surface. The sleeve retainer  76  includes elongate openings formed around its circumference formed to receive electrical supply contacts  62  therethrough. The openings&#39; elongate sides are shown generally aligned with the sleeve retainer  76  axis A X . Each contact  62  includes a recessed lip  78  around its periphery that exceeds the respective openings&#39; dimensions. When the contacts  62  are aligned coplanar with the openings, the lips  78  contact the openings&#39; outer edge. While, as shown, the contact  62  can be restrained in place by the lip  78  and opening size difference, the contacts&#39;  62  thicker midsection can extend radially inward past the contactor assembly  56  inner circumference. In the embodiment shown, the sleeve retainer  76  includes a recess around the opening edge that corresponds to the lip  72 . Springs  80  are also shown providing a force urging the contact  62  towards the sleeve retainer  76  axis A X . An insulator  82  may be provided between the sleeve retainer  76  and the upper member  65 . The insulator  82  may be pliable and formed from a non-conducting material such as polyetheretherketone (PEEK). The insulator  82  can also be another non-conductive material in the thermoplastic family. 
         [0025]      FIG. 2  illustrates a sectional view of the receptacle assembly  55  of  FIG. 1  taken along section line  2 - 2 . Here three keys  63  are shown attached to the receptacle assembly  55  inner surface by welds  37  and spaced substantially equidistance apart. However the keys  63  can be affixed by any other suitable attachment means and are not limited to the spacing shown. Although three keys  63  are shown protruding into the bore in  FIG. 2 , other numbers of keys  63  could be included with the device shown herein. 
         [0026]      FIG. 4  illustrates a sectional view of the coupling adapter  56  of  FIG. 3  taken along section line  4 - 4 . Three supply contacts  62  are illustrated substantially equidistant from one another; the contacts  62  are not limited to this arrangement. Moreover, the contacts  62  could also be disposed at different elevations within the coupling adapter  56 . 
         [0027]      FIGS. 5A-5C  illustrate a side partial sectional view of an example of a deployed assembly  34  attached to the bottom end of an electrical submersible pumping (ESP) system  20 . The deployed assembly  34  described herein includes a volume of a purging fluid, a device or system to purge an area using the fluid, and a device that couples with a tubing string. The fluid can be used for purging an area free of unwanted fluid, and is preferably non-conductive. Dielectric fluid is an example of a purging fluid suitable for the system and method disclosed herein. The fluid can be any media and can include dielectric grease, a mixture of fluids, solvent, and a combination of these alternatives. Shown in  FIG. 5A  is a generally cylindrically shaped conductor adapter head  35  provided on the deployed assembly  34  upper end. The adapter head  35  bolts to the lower end of a motor  22  from the ESP system  20 . Electrical connectivity to the motor  22  is provided by a motor electrical receptacle  85  shown connected to a motor lead line  84 . The receptacle  85  is anchored in an insulator block  87  within a cavity formed on the adapter head  35  upper end. An optional passage (not shown) can be included through the block  87  to allow for pressure equalization between the motor  22  and the deployed assembly  34 . A check valve may be included within the passage. A motor electrical connection pin  23  which extends from the motor  23  is shown inserted within the receptacle  85 . 
         [0028]    The adapter head  35  includes profiled channels  36  on its outer surface shown having decreasing width from their respective openings to about the channels&#39;  36  midpoint; upward from their midpoints, the channels&#39;  36  width remains substantially constant. An upper reservoir  92  is housed within the adapter head  35  and shown filled with a purging fluid  41 . Port  90  communicates the upper reservoir  92  with the reservoir  40 . A sectional view of the adapter head  35  taken along section line  6 - 6  from  FIG. 5A  is provided in  FIG. 6 . This view depicts three profiled channels  36  in a section having a constant width. Also shown are the motor lead lines  84  exiting ports  94  formed in a bulkhead  88  ( FIG. 5A ) provided at the adapter head  35  lower terminal end. The bulkhead  88  shown also includes an orifice  90  formed axially therethrough roughly at its midsection. 
         [0029]    The adapter head  35  lower end coaxially attaches to a housing  38  covering the deployed assembly&#39;s  34  mid portion. A reservoir  40  is shown coaxially provided within the housing  38  coupled to the bulkhead  88  on its upper end. Purging fluid  41  is stored in the reservoir  40  communicatable to the upper reservoir  92  through the orifice  90 . An annular space  86  is shown formed in the housing  38  wall and oriented generally parallel to the housing  38  axis. The annular space  86  registers with the port  94  at its upper end. 
         [0030]    Referring now to  FIG. 5B , the motor lead line  84  exits the annular space&#39;s  86  bottom end into a passage  83  formed in a rod guide  50 . The passage  83  upper end registers with the annular space  86  bottom and the passage  83  lower end terminates at the rod guide  50  bottom. The lead line  84  emerges from the passage  83  into an open space  93  in the housing  38  where it connects to a contact assembly  44 . The rod guide  50  is a generally annular member shown coaxially affixed within the housing  38  and circumscribing the upper portion of a piston rod  43 . A piston  42  on the rod  43  upper end is held in the lowermost portion of the reservoir  40 . A bore  73  radially formed within the rod guide  50  registers with a groove  47  provided in the piston rod  43 . A shear pin  49  inserted into the bore  73  extends into the groove  47 , thereby maintaining the rod  43  and piston  42  in place as shown. The piston rod  43  lower end connects to a cylindrical plunger  48 ; a seal  77  is shown on the plunger  48  outer periphery ( FIG. 5C ) configured for sealing insertion into the lower PBR  60 . 
         [0031]      FIG. 7  illustrates a sectional view taken along line  7 - 7  from  FIG. 5B . In this view multiple passages  83  are shown axially formed in the rod guide  50 , some of which include motor lead lines  84 . As will be discussed in more detail below, passages  83  can provide a flow path for the purging fluid  41  from the annular spaces  86  to flow into the open space  93  below the rod guide  50 . Referring back to  FIG. 5B , the contact assembly  44  includes a conductor  46  connected to the motor lead line  84  and partially housed in an insulating boot  45 . A tapered sleeve  39  is provided around the piston rod  43  where the boot  45  rests against the sleeve  39 . The sleeve  39  cross section is frusto-conical, and thicker below its contact area with the insulating boot  45 . 
         [0032]    Openings provided in the housing  38  are shaped to allow the conductor  46  to protrude radially outward past the housing  38  outer surface. As shown, the conductor  46  is retained within the space  93  by retaining springs  71  that circumscribe the piston rod  43  at the upper and lower portions of the boot  45 .  FIG. 8  represents a sectional view taken at lines  8 - 8 , which is at two different elevations on the housing  38 . In  FIG. 8 , three contacts  46  with their respective insulating boots  45  are depicted; with one shown in a sectional view and the others in an overhead view spatially showing a retaining spring  71  coupling with the insulating boots  45 . The retaining spring  71  can comprise a c-ring. 
         [0033]    Referring back to  FIG. 5B , further illustrated is an insulation base  79  attached to the housing  38  lower end; an opening is axially formed through the base  79  that circumscribes the tapered sleeve  39  lower end. A collar  52  is attached to the piston rod  43  just below the tapered sleeve  39 ; the collar  52  upper end also resides in the opening. A groove  51  circumscribing the sleeve  52  outer surface registers with a bore  81  radially formed in the insulation base  79 . A shear pin  53  is inserted through the bore  81  and into the groove  51 , thereby further retaining the piston rod  43  in place. A passage  94  is formed through the insulation base  79  between the open space  93  and the base  79  lower end. A check valve  95  disposed in the passage  94  permits single direction flow from the space  93 . 
         [0034]      FIGS. 9A and 9B  illustrate in sectional view an embodiment of the deployed assembly  34  being landed in the receptacle assembly  55 . As shown, the plunger  48  is inserted within the lower PBR  60 , blocking flow through the bore  61 . Further, the profiled channel  36  is above the key  63  and the conductor  46  is above the supply contact  62 . Fully coupling the deployed assembly  34  within the receptacle assembly  55  involves mating the key  63  in the profiled channel  36  and providing electrical contact between the conductor  46  and the supply contacts  62 . Moreover, the space around the supply contacts  62  should be washed free of debris and any electrically conducting fluids purged away. This may be accomplished by the purging fluid  41  supplied in the deployed assembly  34 . 
         [0035]    After the deployed assembly  34  is lowered and the plunger  48  is forced into the lower PBR  60 , the ESP system  20  and deployed assembly  34  combined weight applies a force that overcomes the shear pins&#39;  49  resistive strength. The applied force shears the pin  49  thereby allowing piston rod  43  and piston  42  movement with respect to the remaining components in the deployed assembly  34 . More specifically, the deployed assembly  34  slides downward over the piston rod  43 , which in turn pushes the piston  42  into the reservoir  40 . The moving piston  42  forces purging fluid  41  from the reservoir  40 , through the orifice  90  and port  94 , and into the annular spaces  86 . Continued upward piston  42  movement ultimately empties the fluid  41  from the reservoir  40  to fill and pressurize the open space  93  below the annular spaces&#39;  86  exits. After the space  93  is filled with the purging fluid  41 , the check valve  95  opens to allow flow through the passage  94  for purging wellbore fluid from the coupling adapter  56 . The purging fluid  41  density exceeds wellbore fluid density, which forces the wellbore fluid upward from within the coupling adapter  56  in the space between the receptacle assembly  55  and the deployed assembly  34 . As shown, the shear pin  53  is sheared while the deployed assembly  34  is reaching the final stage of landing within the receptacle assembly  55 . This occurs as the plunger  48  contacts the collar  52 , which forces the tapered sleeve  39  upward extending the combined boot  45  and conductor  46  outward engaging/making contact with supply contact  62  in the final stages of the landing process. 
         [0036]    Optionally, the check valve  95  may be configured to open at a specific set pressure. The set pressure can be set based on wellbore fluid pressure, on the space  93  pressure when substantially filled with purging fluid  41 , or another design criterion. Establishing a suitable set pressure is within the scope of those skilled in the art. 
         [0037]      FIGS. 10A and 10B  depict partial sectional views of the deployed assembly  34  fully landed in the receptacle assembly  55 . In one example, a fully landed deployed assembly  34  has its weight supported by the receptacle assembly  55 , including the weight of an associated ESP system  20 . A fully landed deployed assembly  34  may also be engaged by the receptacle assembly  55  to prevent deployed assembly  34  rotation. A fully landed deployed assembly  34  may also be oriented in a pre-selected azimuth within the receptacle assembly  55 , where a pre-selected azimuth aligns electrical contacts in the deployed assembly  34  with electrical contacts in the receptacle assembly  55 . 
         [0038]      FIGS. 10A and 10B  provide an example of supporting the deployed assembly  34  within the receptacle assembly  55  by engaging the key  63  and the profiled channel  36 . Alternatives exist having multiple channels  36 . Preferably the opening or openings on the channel(s)  36  circumscribing the deployed assembly  34  are profiled with sufficient width so a key  63  is engaged with an opening irrespective of the assembly&#39;s  34  azimuthal orientation. After a channel  36  opening engages a key  63 , the profiled channel  36  angled surface slides on the key&#39;s  63  upper surface, which rotates the deployed assembly  34 . The channel  36  slides on the key  63  until the key  63  top is aligned with the constant width portion of the profiled channel  36 . At this point, the deployed assembly  34  drops to insert the key(s)  63  into the constant width portion of the profiled channel  36 . The key  63  and channel  36  coupling locks the deployed assembly  34  to prevent its rotation.  FIG. 11  provides a sectional example taken along line  11 - 11  from  FIG. 10A  depicting key  63  and profiled channel  36  in full engagement. In this example, shown are three keys  63  with corresponding profiled channels  36 , however the device presented herein is not limited to this number and can include fewer or more. Additionally, strategic key  63  and channel  36  placement provides a desired deployed assembly  34  orientation. 
         [0039]    An example of electrically coupling the conductor  46  and supply contact  62  is illustrated in  FIGS. 10A and 10B . Orienting the deployed assembly  34  can align the conductor  46  with the supply contact  62 . As noted above, a portion of the supply contact  62  extends radially inward past the sleeve retainer  76 . The conductor  46  is moved radially outward into electrical contact with the supply contact  62  by the tapered sleeve  39  being moved upward so its thicker portion is behind the insulated boot  45 . Moving the piston rod  43  so the sleeve&#39;s  39  thicker portion is between the insulating boot  45  and the piston rod  43  radially pushes the conductor  46  outward into engaging contact with the supply contact  62 . Electrically engaging the conductor  46  and the supply contact  62  provides a continuous path to flow electricity to the motor  22  from the power cable  66 .  FIG. 12  provides a sectional example taken along line  12 - 12  from  FIG. 10B  depicting conductor  46  and the supply contact  62  full engagement. In this example, shown are three conductors  46  with corresponding supply contacts  62 , however the device presented herein can have other numbers of conductors  46  and contacts  62 . 
         [0040]    The seal  77  between the plunger  48  and the lower PBR  60  retains the purging fluid  41  in the space between the deployed assembly  34  and receptacle assembly  55 . Retaining the purging fluid  41  in this space prevents the displaced fluid from returning to within the coupling adapter  56 , thereby isolating the conductor  46  and supply contact  62  from electrolytic fluid interference or other contaminants. The sealing function between the plunger  48  and the lower PBR  60  can occur as soon as these members are coupled. 
         [0041]    Referring now to  FIG. 13 , a side view example of the ESP system  20  and attached deployed assembly  34  is depicted fully landed within the receptacle assembly  55 , which is illustrated in a partial sectional view. As noted above, fully landing the deployed assembly  34  within the receptacle assembly  55  anchors an associated ESP system  20  against rotation so it can be operational. Further, fully landing the deployed assembly  34  within receptacle assembly  55  provides electrical power for energizing the pump of the ESP system  20 .  FIG. 13  illustrates formation fluid  13  (illustrated by arrows) entering the well bore  5  from perforations  11  that extend into the formation  9  through the casing  7 . The fluid  13  can be delivered for pumping to the pump  20  via the inlet passages  68  and then onto pump inlets (not shown). Optional exit passages above the pump may be include to allow for vapor escape from the tubing  54 . 
         [0042]    The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. For example, a supply of purging fluid or media could be pressurized and sealed in a vessel that is selectively opened to discharge the purging fluid. Selectively opening could include opening a valve or rupturing the vessel. Optionally, each ESP system  20  components can be installed in separate downhole deployments. For example, the motor, seal section, intake, and pump could be deployed individually, or in combination, to allow flexibility of the system string installation. These and other similar modifications will readily suggest themselves to those skilled in the arts and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.