Patent Publication Number: US-10760350-B2

Title: Submersible pump cable connector assembly

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to electrical connectors, and more particularly to electrical connectors for submersible electric pumps. 
     In the oil and gas industry, submersible electric pumps are utilized to pump crude oil from within the well head. The environment within the well head in which the pumps and associated electrical conductors operate makes the electrical connections within the wellhead susceptible to corrosion, fatigue, and ultimately disruption of electrical conduction necessary to operate the pumps. The conductors within the well head must also effectively routed to the exterior of the well head to permit connection to an external power source outside to operate the pump. 
     From time to time, the conductor cables within the well head may require repair or replacement. At other times, the pump may be relocated to a different well head and the conductor cables may be replaced as a precaution to accomplish a fresh installation. The repairs will typically require a splice connection of the conductors. The individual conductors within the heavy gauge multi-conductor cables, typically electrical submersible pump (ESP) cables, are normally oriented in flat side by side configuration. Due to the heavy gauge, the individual conductors in the cables are typically very rigid. Accordingly, adequate separation of the conductors is needed in order to apply a splice with conventional splicing tools. 
     Once the splice is accomplished, it is important to maintain separation of the spliced connections while sealing the spliced connections for protection from the severe environmental conditions within the well head. 
     As can be seen, there is a need for an improved connector for sealing the electrical conductors within the well head and providing for an exterior connection to an external power source. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention an electrical connector assembly for a wellhead is disclosed. The connector assembly includes an elongate cartridge, having a top end, a bottom end, and an interior cavity defined between the top end and the bottom end that is configured to contain a splice connection between a multi-stranded ESP conductor carried in a well bore and a plurality of power pins extending from a top end of the cartridge external to the well head. A resilient bottom seal has an elongate slot dimensioned to receive an outer sleeve of the multi-stranded ESP conductor and an exterior dimension to resiliently engage with a wall of the interior cavity. A retainer block and a pressure block configured to be received in an intermediate portion of the cartridge, the retainer block and the pressure block having an axially aligned aperture to carry each of the plurality of power pins in a spaced apart relation within the interior cavity. A splice chamber is defined between the retainer block and the bottom seal. 
     The electrical connector assembly may also include a boot configured to be sealingly received in the top end of the of the elongate cartridge, the boot having a bore to receive each of the plurality of power pins in a radial disposition about a longitudinal axis of the cartridge. A power pin chamber is defined between the boot and the pressure block. The power pin chamber is adapted to carry the plurality of power pins in a spaced apart relation. 
     A restrictor rotationally restricts the movement of the power pins within the interior cavity. In some embodiments, the restrictor may include one or more set screws that are received through the wall of the elongate cartridge and received in one or more of the pressure block and the retaining block. In other embodiments, the restrictor may be a keyed slot defined in one of the pressure block and the retaining block and a corresponding protrusion extending from the wall of the interior cavity. 
     The length of the power pin chamber corresponds to a length of the plurality of power pins selected for the well head. The cartridge may also include at least one injection aperture defined in the wall of the cartridge. The injection aperture is dimensioned to receive an injection tip of a potting material injector. 
     In other embodiments, a seal sleeve is adjustably positionable along a length of the top end of the cartridge. An annular groove inscribing an interior surface of the seal sleeve is configured to receive an O-ring for sealing engagement with an exterior wall of the cartridge. Likewise, an annular groove circumscribing an exterior surface of the seal sleeve is configured to receive an O-ring for sealing engagement with a bore of the well head. The seal sleeve may also include an annular lip circumscribing the exterior surface of the seal sleeve. The annular lip is configured as a stop to engage a top end of the bore of the well head. 
     In some embodiments, a top stub is secured to the top end of the cartridge. The top stub includes an annular groove inscribing an interior surface of the top stub that configured to receive an O-ring for sealing engagement with an exterior wall of the cartridge. Preferably, the top stub has a length at least as long as a terminal end of the plurality of power pins extending from the top end of the cartridge. The top stub is configured to receive a cannon plug connection to a power supply. 
     In other embodiments, the cartridge has an alignment indicator defined on an exterior surface indicating an alignment of the power pins carried within the cartridge. In yet other embodiments, a potting material is received within the power pin chamber. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the cable connector, shown assembled with bullnose protector  32  and pre-crimped flat ESP cable  52  in place; 
         FIG. 2  is an exploded view of the connector, with barrier assembly parts preset onto ESP cable  52 ; 
         FIG. 3  is a section view of the connector, taken along line  3 - 3  in  FIG. 1 ; 
         FIG. 4  is a detail section view of the connector; 
         FIG. 5  is a detail section view of the connector; 
         FIG. 6  is a section view of the connector, taken along line  3 - 3  in  FIG. 1 ; 
         FIG. 7  is a section view of the connector, taken along line  7 - 7  in  FIG. 1 ; 
         FIG. 8  is a detail perspective view of the connector, illustrating the removal of set screw  26  to insert potting compound injector  70 ; 
         FIG. 9  is a detail section view of the connector with potting compound  72  in place; 
         FIG. 10  is a perspective view of the connector, illustrating the removal of bull nose protector  32  in order to install seal sleeve  38  and top sub  40 ; 
         FIG. 11  is a perspective view of the connector, shown assembled with seal sleeve  38  and top sub  40 ; 
         FIG. 12  is a section view of the connector, taken along line  12 - 12  in  FIG. 11 ; 
         FIG. 13  is a perspective view of the connector, shown installed in a wellhead; 
         FIG. 14  is a schematic section view of the connector, taken along line  14 - 14  in  FIG. 13 , with the connector shown in full and the wellhead components shown as hidden for clarity; and 
         FIG. 15  is a detail sectional view of the connector with a barrier reinforcement. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
     Broadly, embodiments of the present invention provide an improved electrical connector for an electrical pump conductor installation in a well head. As seen in reference to the drawings of  FIGS. 1-3 , the connector includes an elongate body, or cartridge  24 , that is preferably formed of a durable rigid material, such as stainless steel. The cartridge  24  has an interior cavity for containing a connection end of a stranded ESP conductor  52 . The conductor  52  extends between the well pump and the interior cavity. A bottom seal carries the conductor  52  and seals the interior cavity of the cartridge  24  from infiltration of contaminants from within the wellhead  90 . A retainer block  16  and pressure block  20  are positioned at an intermediate portion of the cartridge  24  provides separation of the conductor strands  54  and the power pins  46  within the cartridge  24 . A splice chamber is defined at a down hole end of the cartridge  24  between the bottom seal and the pressure and retainer blocks  26 ,  20 . A power pin chamber is defined between the pressure block  20  and a top seal  30  and is dimensioned to carry a plurality of power pins  48  between the splice chamber and the exterior of the well head  90 . 
     As best seen in reference to  FIGS. 3, 4, 6, and 9 , the bottom seal includes a barrier nut  10  and a barrier plate  12  disposed on opposite sides of a barrier  14 . The barrier plate  12  and the barrier  14  have an elongate slot formed therein that is dimensioned to closely conform to the outer protective sleeve of the ESP cable  52 . The barrier nut  10  is configured to threadingly engage with a bottom end of the cartridge  24 . The barrier plates  12  compress the barrier  14  between the bottom end of the cartridge  24  and an interior of the barrier nut  10  as the barrier nut is tightened to the end of the cartridge  24  to seal the end of the cartridge  24  and prevent infiltration of contaminants around the outer protective sleeve of the ESP cable  52 . The barrier  14  may be formed of a rubber or elastomeric material, while the barrier plate  12  may be formed of a rigid material, preferably stainless steel. The barrier plate  12  is dimensioned to abut a mechanical shoulder defined in an end of the elongate cartridge  24 . For higher pressure applications, a reinforced barrier plate  12  may include a plurality of barrier plates  12  on a down hole end of the connector  10 . Alternatively, the thickness of the barrier plate  12  may be increased. 
     As best seen in reference to  FIGS. 2, 3, 4, and 9 , each strand of the ESP cable  52  includes a conductor  54  that is surrounded by an insulating layer  50 . Each conductor  54  is joined to a power pin  48  by a splice  48  that is crimped around the joined ends thereof and is contained within the interior cavity at an intermediate position between the top end and the bottom end of the cartridge  24 . The length of the cartridge  24  may be varied to correspond to a length of the power pin  48  that is spliced to the conductor  54 . A high temperature tape wrap  80  may be utilized to cover the joined ends of the conductor  54  and the power pins  46  and their respective insulating layers. Likewise, a high modulus tape wrap  78  may be applied around the high temperature tape wrap  80 . 
     A retaining block  16  has a plurality of bores defined in a spaced apart relation through the retaining block  16 . Each bore receives a power pin  48  and maintains the power pins  48  in a spaced apart relation. The retaining block  16  is received within the cartridge  24  and is retained in place via a plurality fasteners, such as the retaining block set screws  26  so that the retaining block  16 , and the conductors carried by the retaining block  16  are rotationally locked to prevent twisting of the conductors. Alternatively, the retaining block  16  and/or the pressure block  20  may be configured with a keyway or slot to align with a corresponding protrusion on an interior of the cartridge  24 . 
     Because the conductors  54  and power pins  46  are concealed within the assembly, rotationally locking the conductors  54  ensures proper alignment of the power pins  46  relative to an external indicator  76  so that the power pins  46  can be connected to the electrical power source. 
     Likewise, maintaining the alignment of the ends of the power pins  46  and their axial position ensures that the power pins  46  each make a sound electrical connection with the connector to the electrical power source. An adjacent face (in an up whole direction) of the retaining block  16  has a shouldered recess defined within each of the retaining block bores. The shouldered recess receives a retaining device  18 , such as a clamp, clip, or ring that clamps into a gap in the insulation of the power pin polyetheretherketone (PEEK). The retaining devices  18  are secured between the pressure block  20  and the retaining block  16  to axially secure the power pins  46 . An epoxy bonding agent may be positioned in proximity to the splice  48 . 
     As best seen in reference to  FIGS. 4 and 9 , a pressure block  20  has a plurality of bores defined in a spaced apart relation, coaxially aligned with the bores in the retaining block  16 . Each pressure block bore has at least one inner pressure block O-ring  56  to sealingly engage with an outer surface of the power pin  46 . An outer surface of the pressure block  20  has at least one outer pressure block O-ring  56  that is received within an annular groove surrounding the pressure block  20 . The pressure block  20  and outer pressure block O-ring  56  are dimensioned for sealing engagement with an interior wall of the cartridge  24 . An up hole face of the pressure block  20  is positioned against an annular shoulder defined within the cartridge  24  at the pressure block. 
     At least one cartridge O-ring  44  is received in a channel circumscribing an exterior surface of the cartridge  24  proximal to the pressure block  20 . The cartridge O-ring  44  is dimensioned for sealing engagement of the cartridge  24  within an internal bore of the wellhead  90 . 
     As best seen in reference to  FIGS. 3, 5, and 12 , an upper end of cartridge  24  extends from the pressure block  16  to the terminal end of the cartridge  24 . A rubber boot  30  has a plurality of bores through which the power pins  46  extend. The boot is dimensioned to be received within the end of the cartridge  24 . The power pins  46  extend through the rubber boot  30 . 
     A seal sleeve is  38  is received around the upper end of the cartridge  24 . The seal sleeve  38  has inner sleeve O-rings  64  for mating engagement with an exterior surface of the cartridge  24 . At least one outer sleeve O-ring  66  is carried in an annular groove circumscribing the sleeve. The outer sleeve O-ring  66  is dimensioned for sealing engagement with an aperture defined in a top end of the wellhead  90 . The seal sleeve  38  has an aperture and set screw  88  for securement of the seal sleeve  38  to the cartridge  24  at a desired position within the wellhead  90 . 
     A top stub  41  is received at the top end of the cartridge  24 . The top stub  41  has an aperture and set screw  42  to secure the top stub  41  to the end of the cartridge  24 . At least one annular channel on an interior surface of the top stub  41  receives an O-ring  60  for sealing engagement of the top stub  41  and the exterior wall of the cartridge  24 . An annular channel is defined around an exterior wall of the top stub  41  and is configured to receive an external top stub O-ring for sealing engagement with a cannon plug connector  40  or protective endcap. The top stub  41  may also have one or more alignment marks  74  to provide a visual reference for alignment of the cannon plug connector  40  with the power pins  46  carried by the cartridge  24 . Each power pin  48  is then carried through the top seal  30  to a point external of the wellhead  90 . The power pin  48  may also have an insulating layer  82 . A bullnose protector  32  may be provided to attach to the end of the cartridge  23  so that the external ends of the power pins  48  are protected from the elements. In use, the power pins  48  are connected to an electrical power source external of the wellhead  90 . 
     As seen in reference to  FIG. 8 , the cartridge  24  includes one or more injection apertures  86  that allow for the injection of a potting compound  72  to the interior cavity of the cartridge  24 . A set screw, or plug  68  may then be inserted into the aperture  86  to seal the potting compound  72  within the cartridge  24 . In a field environment, the potting compound  72  may be injected with an injection gun  70 . 
     It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.