Abstract:
A tool is run into a liner that holds an electrical or hydraulic connection for a downhole tool which preferably is an electric submersible pump (ESP). It is capable of cleaning the electrical contacts, replacing them, isolating them from well fluid if no ESP or other downhole tool is to be present for a long time or switching from a main to a backup supply cable or hydraulic line among other downhole functions. The ability to use the tool takes away the need to pull the liner with the exterior cable or hydraulic line attached. It further allows the ESP or another downhole tool to be put back in service faster. Applications to other tools that obtain power or hydraulic pressure in a downhole wet connection are contemplated.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of this invention is maintenance and reconditioning of a downhole stab type electrical or hydraulic connectors and more particularly permanently installed connectors adapted for powering down hole equipment such as an electric submersible pump (ESP) including contact replacement or reconditioning or replacement of down hole hydraulic stab sealing surfaces or switching power cables or hydraulic lines as some examples of tool functionality. 
       BACKGROUND OF THE INVENTION 
       [0002]      FIGS. 1-3  refer to the current state of the art. A liner  10  is installed in casing  12  with an optional packer  14 . A cable or hydraulic line  16  runs outside the liner  10  and can carry power, communication or control lines for the operation of the ESP or down hole equipment  18  when it is mated to the electrical or hydraulic stab  20 . The cable or hydraulic line  16  comes through an opening  22  in the liner  10  and into a shoe  24 . The stab  20  can have spaced circumferential contacts such as  26  and  28  separated by an insulating band  30  in an alternating pattern to present as many contact locations as necessary for proper operation of the ESP. The ESP has a receptacle  32  that lands on the stab  20  with a complementary set of contacts to engage contacts  26  and  28  so that the ESP when fully landed has full functionality. There are many existing methods of aligning electrical contacts or hydraulic connections that may be used. The ESP  18  can be delivered on wireline or electric line  34  and carry a latch  36  to engage a profile (not shown) within the liner  10  for stabilization. A packer  38  can be set and the installation line  34  released and the ESP  18  can be operated to boost pressure of well fluids to get them to the surface in the familiar manner. 
         [0003]    The state of the art in ESP connections downhole is reflected in the following U.S. patents and Publication Numbers: 2002/0050361 (see  FIG. 8 ); U.S. Pat. Nos. 6,415,869; 4,589,492; 1,801,731; 4,997,384; 5,389,003; 6,154,953; 6,398,583; 7,291,028; 7,404,725; 7,462,051 and 2007/0275585. 
         [0004]    What is need and is addressed by the present invention are options for maintenance downhole when the ESP is in position and there are issues with the connector that controls it. Pulling the liner with the power cable and the shoe that supports the stab  20  is an extreme and costly measure that is better off avoided. There are many potential connector issues that can develop that can be addressed without pulling the liner with a tool of the present invention. The electrical or other contacts can be remotely cleaned in place by a tool that is delivered to the stab  20 . The tool can also grasp a connector and replace it. The tool can uncover surplus connectors that are temporarily covered to allow continued operation. The tool can protect what would otherwise be exposed connectors if there is no ESP to be installed for a long time on the stab  20 . Another option for the tool is to switch cables where the liner is provided with a backup cable. The common theme to all these operations is that they are done remotely with a tool inserted through the liner that holds the shoe  24  with the stab  20  so that the liner  10  does not need to be removed. Those skilled in the art will better understand the invention from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is determined by the appended claims. 
       SUMMARY OF THE INVENTION 
       [0005]    A tool is run into a liner that holds an electrical or hydraulic connection for a downhole tool which preferably is an electric submersible pump (ESP). It is capable of cleaning the electrical contacts, replacing them, isolating them from well fluid if no ESP or other downhole tool is to be present for a long time or switching from a main to a backup supply cable or hydraulic line among other downhole functions. The ability to use the tool takes away the need to pull the liner with the exterior cable or hydraulic line attached. It further allows the ESP or another downhole tool to be put back in service faster. Applications to other tools that obtain power or hydraulic pressure in a downhole wet connection are contemplated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a prior art liner with a shoe supporting a male connector looking uphole; 
           [0007]      FIG. 2  is the view of  FIG. 1  showing an ESP assembly about to be landed on the connector; 
           [0008]      FIG. 3  is the view of  FIG. 2  with the ESP fully landed on the connector; 
           [0009]      FIG. 4  shows the maintenance tool of the present invention coming close to a male connector in a shoe downhole; 
           [0010]      FIG. 5  shows the tool of  FIG. 4  fully landed on the male connector; 
           [0011]      FIG. 6  shows an enclosure over the male connector to isolate it from well fluids until ready for use that can be penetrated to connect an ESP; 
           [0012]      FIG. 7  is the view of  FIG. 6  with the ESP penetrating the enclosure to make contact; 
           [0013]      FIG. 8  is the view of  FIG. 7  with the ESP removed and the maintenance tool repositioned to work on contacts or to reseal the enclosure until further use; 
           [0014]      FIG. 9  shows a liner with multiple cables to feed the contacts in the male connector with the cable on the left initially connected; 
           [0015]      FIG. 10  is the view of  FIG. 9  with the maintenance tool landed in position to switch cable feeds; 
           [0016]      FIGS. 11   a - 11   d  show the sequence where the tool switches connection from one cable to another; 
           [0017]      FIG. 12  shows a remote multi-function tool run in toward an existing shoe; 
           [0018]      FIG. 13  is the view of  FIG. 2  with the tool landed on the shoe; 
           [0019]      FIG. 14  is the view of  FIG. 13  with a first operating head moved into position over the shoe; 
           [0020]      FIG. 15  is the view of  FIG. 14  shows the operating head gripping the sealing cap on the shoe for eventual removal; 
           [0021]      FIG. 16  is the view of  FIG. 15  showing the cap removed from the shoe; 
           [0022]      FIG. 17  is the view of  FIG. 16  with the sealing cap shifted to the side in the tool to permit further operations; 
           [0023]      FIG. 18  is the view of  FIG. 17  shows a contact removal head moved into position above the contact to be removed; 
           [0024]      FIG. 19  is the view of  FIG. 18  shows the contact gripped prior to removal; 
           [0025]      FIG. 20  is the view of  FIG. 19  showing the old contact removed and lifted; 
           [0026]      FIG. 21  is the view of  FIG. 20  showing the old contact shifted laterally out of the way to facilitate the next operation; 
           [0027]      FIG. 22  is the view of  FIG. 21  showing the operating ram lifted to access other operating heads; 
           [0028]      FIG. 23  is the view of  FIG. 22  showing an operating head with new contacts shifted into position to be operated by the operating head; 
           [0029]      FIG. 24  is the view of  FIG. 23  showing the new contact brought down into position on the shoe; 
           [0030]      FIG. 25  is the view of  FIG. 24  showing the operating head retracted after installing the new contact; 
           [0031]      FIG. 26  is the view of  FIG. 25  showing the operating head for the new contact that is now empty moved laterally to facilitate subsequent operations; 
           [0032]      FIG. 27  is the view of  FIG. 26  with the operating ram lowered in preparation for reinstalling a protective cover on the newly installed contact; 
           [0033]      FIG. 28  is the view of  FIG. 27  showing the sealing cap brought into alignment with the newly installed contact; 
           [0034]      FIG. 29  is the view of  FIG. 28  showing the sealing cap installed onto the new contact; 
           [0035]      FIG. 30  is the view of  FIG. 29  shows the operating head that delivered the sealing cap now retracted up; 
           [0036]      FIG. 31  is the view of  FIG. 30  shows the operating head for the sealing cap moved laterally out of the way for subsequent operations; and 
           [0037]      FIG. 32  is the view of  FIG. 31  shows the remote multipurpose tool being removed from the downhole shoe. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0038]    Looking at  FIG. 4  the tool  40  can be delivered in a variety of ways generally shown as  42 . Coiled tubing can be used or electric line. Slickline can be used with an onboard power supply schematically illustrated as  44 . Rigid tubing can also be used as another option. Which option is used will depend on cost as determined by the available rig equipment on the surface. The tool  40  has a lower end housing  46  with a downhole oriented opening  48  designed to accept the male connector  50  that has spaced circumferential contacts  52  and  54  that are separated axially by a ring of an insulator  56 . The tool  40  internal to the housing  46  features axially oriented brushes  58  on rotating shafts  60 . The brush segments  58  can be spaced so that when the tool  40  is fully landed the segments of the brush  58  will align with the contacts such as  52  and  54  to polish them and to remove buildup that can or has interrupted contact with the ESP  62  shown in  FIG. 7 . Alternatively the brush material  58  can have an axial length to span all the contacts and the insulators between them when the tool  40  is fully landed as shown in  FIG. 5 . The shafts can be symmetrically distributed in the tool  40  and preferably even in number so that half turn one way and half the other way so that the tool  40  is not subjected to a net torque and will not tend to rotate about its longitudinal axis when all the brushes are turning. This alternative could be more useful if the tool  40  is run on rigid tubing. Alternatively, the tool body  64  can be rotatably mounted to the support  42  and driven to rotate on its own axis such as with onboard power supply  44  or a remote power feed that comes along the support  42 . Alternatively, the cleaning tool may use a reciprocating motion with a shaped circumferential cleaning tool or a combination of reciprocating and rotating motion. A simple pair of contacting wheels or gears should develop enough power to spin the housing  64  on its axis as the brushes  58  are rotated on shafts  60 . As another alternative, if all the shafts  60  are turning the same direction, a net force will develop that will walk the brushes  58  around the respective contacts that they are trying to clean. While the brushes  58  can be bristles made of fiber or metal other forms of mechanical or chemical cleaning are contemplated such as using spray jets to remove debris or chemicals that will not attack the contacts  52  and  54  but will dissolve or otherwise remove the debris that has accumulated on them are all contemplated to be a part of the invention. 
         [0039]      FIG. 5  shows the tool  40  with the brushes  58  aligned with the contacts such as  52  and  54  for cleaning them. The contacts  52  and  54  can be configured to be removable and replaceable with the tool  40 . For example the contacts  52  and  54  can be semi-circular with retainers that can be operated with the tool  40  with one set of rotating members that can release the fasteners while grasping the contact to radially retract it. A replacement contact can also be in position to be articulated into position to replace the contact just removed by repositioning the housing  64  a predetermined amount so that the replacement contact can be pushed in radially and secured with the same fasteners that held its predecessor. In this manner the tool  40  can replace one to all the contacts downhole without a need to remove the liner  66 . 
         [0040]    Referring to  FIG. 6  the male connector  68  can be enclosed in a cylindrical housing  70  and filled internally with fluid  72  that will prevent well fluids from reaching the contacts on the connector  68  that is wholly within the housing  70 . The housing  70  can have a removable cover  74  that can be penetrated or otherwise removed by the advancing female component cover  76  that carries the female connector  78  whose contacts will align with the contacts on the male connector when the  FIG. 7  position is reached. Thus the initial mating of  78  and  68  is done in the presence of the fluid  72  after the cover is removed or otherwise gotten out of the way. After the ESP  62  is later removed it is desirable to protect the connector  68  if it will be a long time before another ESP will be lowered into position. The tool  80  be lowered in and deliver replacement fluid  72  and a cover  74 ′ over it and fasten it to the housing  70 . 
         [0041]      FIG. 9  shows two cables  82  and  84  going into the shoe  86  with  82  being connected to the male connector  88 . If cable  82  stops working for any reason it is possible to use tool  90  to reconfigure connector  88  to be connected to cable  84  instead of cable  82  so that there is no need to pull the liner  92 .  FIGS. 10 and 11   a  show the tool  90  landed on the male connector  88 .  FIG. 11   b  shows the male connector  88  lifted enough to remove the connecting prong  94  from its receptacle  96  that had allowed cable  82  to be connected to it. In  FIG. 11   c  the male connector  88  is rotated on its axis to now align prong  94  with receptacle  98 . In  FIG. 11   d  the male connector  88  has been lowered to get prong  94  into receptacle  98 . There are alternative ways to do this such as simply rotating the male connector  88  and using flush connectors instead of prong and socket devices that require a pickup force. The connector  88  can have a sealingly and rotatably mounted base that can alternatively make contact with either cable below the base with flush contacts that are sealed off from well fluids. Although alternating between two cables is illustrated, it is also possible to have more than two cables for services where interruptions need to be kept to a minimum. 
         [0042]    The downhole remote operated tool  100  in this operation has multiple tool heads for example  102 ,  104 ,  106  and  108  in several tool locations. Preferably, each tool head has the necessary motors and rams to perform its individual function. Preferably, the motors or rams would be hydraulic but other motivating forces such as electric motors and solenoids are possible as well. There is also an operating ram  110  that can move from storage locations to pick up the tool head required for the particular operation it is required to do. Only 4 tool heads are shown in  FIG. 12  but there may be more as required for the planned operation. 
         [0043]      FIG. 12  shows the tool  100  loaded with an two empty gripper tools  106  and  108 , one gripper tool with a new set of contacts  102 , and a contact cleaner tool  104  being lowered in the well. 
         [0044]      FIG. 13  shows the tool  100  landed on the ESP seating shoe  112 , and sealed to the seating shoe. The tool  100  has a sealing cap  114  installed on its bottom face to prevent well fluid contamination of the inside of the tool  100 . There can be well fluid trapped between the cap  114  and the seating shoe  112  that can be eliminated using several methods. The nose of the tool  100  can be covered with an expendable rubber gasket (not shown) and the cap  114  filled with a clean fluid or gel. The gasket would wipe the seating shoe contacts and surfaces while the gel would be expelled out of the cavity of the cap  114  and seating shoe  112  removing the contaminating well fluid. The tool  100  would then seal against the seating shoe  112 . 
         [0045]    In  FIG. 14  an empty gripper tool head  108  is moved from its storage location to under the operating ram  110 . Necessary hydraulic or electrical connections are made between the gripper  108  and ram  110 . The forces and motions to move the tool  108  from the storage location may be included in the ram  110  or in the storage location. 
         [0046]      FIG. 15  shows the empty gripper tool head  108  moved down to the operating position. It will grip the sealing cap  114  and apply the correct forces and or motions to remove the sealing cap  114  and expose the old set of contacts  116  that are in the well. 
         [0047]      FIG. 16  shows the gripper head  108  with the sealing cap  114  moved up.  FIG. 17  shows the gripper head  108  with the sealing cap  114  moved laterally.  FIG. 18  shows the empty gripper head  106  moved into position below the operating ram  110 .  FIG. 19  shows the empty gripper head  106  moved down to the operating position. It will grip the old contact set  112  and apply the appropriate forces and motions to release the old contact set  112  from the seating shoe. Not shown is that the contacts may require a flushing operation while they are released to prevent hydraulic lock or to eliminate contaminated fluids in the contact receptacle area. A port may be provided down the length of the contact that could be opened by the gripper head  106  and the appropriate fluid flushed into the receptacle area while the contacts  112  are removed. 
         [0048]      FIG. 20  shows the gripper head  106  with the old contacts  112  moved up.  FIG. 21  shows the old contacts  112  and gripper head  106  moved laterally. In  FIG. 22  the ram  110  moves up above new contacts  118  and in  FIG. 23 , the new contacts  118  in a gripper head  102  are moved to below the operating ram  110 . 
         [0049]      FIG. 24  shows the new contacts  118  being moved down to the seating shoe  112 . The gripper head  102  would apply the appropriate forces and motions to the contacts  118  to install them into the seating shoe  112 . If flushing and sealing the contacts is required, that function could be designed into the gripper head tool  100  or it may be in a separate tool that would be used after the gripper head installs the new contacts  118 . Likewise, the opening and flushing operations on the old contact set may be accomplished by a separate tool that is used before the gripper head  106  removes the old contacts  116 . 
         [0050]      FIG. 25  shows the shows the empty gripper head  102  being moved up while  FIG. 26  shows the empty gripper  102  moved laterally into a storage position. 
         [0051]    Other operations may be performed at this time with tool heads designed for this purpose. The contact cleaning tool  104  shown in  FIG. 27  could be used to clean the contacts before the tool is retracted. Also, it would be desirable to be able to check continuity of all the cable lines  82 ,  84  from the surface. A special tool head (not shown) can be moved down to the newly installed contacts  118  and to short them out and allow the cable continuity to be measured from the surface. The cable insulation resistance could be measured at the same time. If the readings are low some troubleshooting or remedial operations may be completed such as cleaning and flushing the contacts. The contacts could be changed from one cable  82  to another  84  using a gripper head. 
         [0052]    The gripper tool  108  and the sealing cap  114  are moved to the operating ram  110  in  FIG. 28 .  FIG. 29  shows the operating ram  110  and moved down to the operating position. The gripper  108  will use the appropriate forces and motions to reinstall and seal the sealing cap  114 . The down hole remote operated tool may be unseated from the seating shoe  112  at this time to using the flushing capability of the gripper tool  100  or a separate tool to equalize the pressure in between the remote operated tool  100  and the seating shoe  112  and prevent a hydraulic lock between the remote operated tool  100  and the seating shoe  112 . The empty gripper  108  is shown being moved up in  FIG. 30 . The empty gripper  108  is moved laterally in  FIG. 31  and the remote operated tool  100  is being removed from the well in  FIG. 32 . 
         [0053]    There are many functions that could be accomplish with a remote operated tool in an oil well such as inspecting, cleaning or replacing permanent instrumentation, or even gas lift mandrels. 
         [0054]    Of course the remote operated tool would be properly instrumented to allow the remote operated tool to be properly controlled by its operator. Temperatures, pressures, voltage, current, vibration and other parameters would be monitored as required as well as appropriate video cameras used to allow the operator to see the operation of the remote operated tool. Of course, appropriate flushing means would be used to keep clear fluid between the video cameras and the area that is being observed. 
         [0055]    The tool head magazine shown has stationary tool head storage locations and a moving ram and operating head. The storage locations may be moved as on a carousel or by a chain drive system or a guided path where the tools heads and storage locations are moved by shoving on the tool heads, or the storage locations or on both, and the operating head may be stationary. Alternatively a combination of movable storage locations and a movable operating head may be used. 
         [0056]    While the preferred applications for servicing wet connections downhole with a variety of tools that avoid removal of the portion of the connection mounted downhole has been in operating ESP, those skilled in the art should understand that other types of downhole tools that require operation or control from the surface can also be used with the assortment of downhole service tools that in the preferred embodiment have covered functions such as contact cleaning or replacement, contact isolation from well fluids such as for periods of extensive downtime, or switching cable feeds to the downhole mounted connection without pulling it out of the hole. 
         [0057]    The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.