US20020050361A1

US20020050361A1 - Novel completion method for rigless intervention where power cable is permanently deployed

Info

Publication number: US20020050361A1
Application number: US09/969,230
Authority: US
Inventors: Christopher Shaw; Earl Brookbank; David Neuroth
Original assignee: Individual
Current assignee: Baker Hughes Holdings LLC
Priority date: 2000-09-29
Filing date: 2001-10-01
Publication date: 2002-05-02

Abstract

A submersible-pump assembly has an electric motor and pump adapted to be lowered into a string of production tubing. A permanently-deployed power cable is located in the annulus located between an outer surface of the production tubing and an inner surface of a string of casing. A set of wet-mateable power connectors provide electricity to the motor through hydraulically-actuated pins carried in hydraulic cylinders mounted to the outer surface of the production tubing. The power cable is connected to each pin for carrying electricity from the surface of the well to the pins. The pins are moved inward toward the motor to engage receptacles located in the outer surface of the motor. Alternatively, the power connectors may be a receptacle that receives a stab mounted to the tubing.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Applicant's copending U.S. provisional application, Serial No. 60/236,485, filed on Sep. 29, 2000.[0001]

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to downhole installations and relates specifically to rigless interventions using electric motors and wet-mateable electrical connections.

2. Description of the Prior Art

Submersible, downhole pumps are used to pump production fluids from deep within wells to the surface when natural flow rates are insufficient. A typical submersible-well-pump assembly comprises an electric motor and a centrifugal pump attached to the motor. Normally, the pump and motor are secured to a lower end of a string of production tubing. To provide electricity to operate the motor, a power cable is attached to the motor and sealed to prevent contact with the production fluids or, in the case of subsea installations, contact with seawater. The power cable extends downward and is usually strapped to the exterior of the production tubing for the entire depth of the installation. When the pump assembly is removed for maintenance or other reasons, the production tubing and the power cable are also withdrawn. The removal and reinsertion of the power cable is difficult and causes wear on the power cable. There have been proposals for permanently-deployed power cables, but these have had various disadvantages.

Therefore, a need exists for a system including a permanently-deployed power cable and providing electric power to downhole, submersible-pump assemblies having motors with conventional configurations.

SUMMARY OF THE INVENTION

A submersible-pump assembly has an electric motor adapted to be lowered into a string of production tubing and a submersible pump mounted to the motor. A permanently-deployed power cable is located in the annulus located between an outer surface of the production tubing and an inner surface of a string of casing. A set of wet-mateable power connectors provide electricity to the motor through hydraulically-actuated pins carried in hydraulic cylinders mounted to the outer surface of the production tubing. The pins in the power connectors are moved into engagement with receptacles in the pump assembly to connect the power cable to the motor for carrying electricity from the surface to the motor.

In a second embodiment, electrical connector pins are mounted to the pump assembly. These pins are moved from a retracted position to an extended position in engagement with receptacles in the production tubing. Hydraulic pressure extends and retracts the pins, the hydraulic pressure being supplied by pumping down the coiled tubing used to run the pump assembly.

In a third embodiment, an arm extends from the inner surface of production tubing and has a stab located near the inner end of the arm. The stab has circumferential, electrically-conductive bands that are connected to the power cable i the annulus. The pump assembly has a receptacle for receiving the stab when the pump assembly is landed in the tubing, the receptacle having contacts for engaging the bands on the stab.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed to be characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings. [0010]
FIG. 1 is a schematic, cross-sectional view of a submersible-pump assembly installed in a downhole location and constructed in accordance with the present invention. [0011]
FIG. 2 is a schematic, cross-sectional view of an alternate configuration of a submersible-pump assembly installed in a downhole location and constructed in accordance with the present invention. [0012]
FIG. 3 is a cross-sectional view of electrical connecting assemblies for use with the submersible-pump assemblies of FIG. 1 or FIG. 2. [0013]
FIG. 4 is an enlarged view of a portion of the connector assemblies of FIG. 3, with the inner and outer connector assemblies shown prior to connection. [0014]
FIG. 5 is a cross-sectional view of the motor and connector assemblies of FIG. 3, taken along the line V-V of FIG. 3. [0015]
FIG. 6 is a schematic, cross-sectional view of a second alternate configuration of a submersible-pump assembly installed in a downhole location and constructed in accordance with the present invention. [0016]
FIG. 7 is a cross-sectional view of electrical connecting assemblies for use with the submersible-pump assembly of FIG. 6. [0017]
FIG. 8 is a cross-sectional view of a third alternate configuration of a submersible-pump assembly installed in a downhole location and constructed in accordance with the present invention. [0018]

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an electric, submersible-pump assembly [0019] 11 installed in a downhole location. Assembly 11 consists of a pump 13, a seal section 14, and a motor 15. A string of casing 16 is cemented to the inner surface of a borehole, and a string of production tubing 17 is located within and generally coaxial with casing 16 to form an annulus 18 between casing 16 and tubing 17. A packer 19, which may be a swab cup, is located at a lower end of production tubing 17 and lies between casing 16 and production tubing 17 to prevent production flow or other fluids from entering annulus 18. A check valve 20 may be installed in the lower portion of production tubing 17 to prevent fluid loss from fluid flowing downward. Check valve 20 also allows for pressure-assisted removal of assembly 11. An additional swab cup 21, or other type of packer, is located between pump 13 and the inner surface of production tubing 17. Swab cup 21 is a lip seal and is preferably run with pump assembly 11. Swab cup 21 allows upward flow past it, but prevents downward flow. As pump assembly 11 is lowered, swab cup 21 slides on the interior of tubing 17 and allows displaced fluid to flow past swab cup 21.
Pump assembly [0020] 11 is assembled by securing a lower end of pump 13 to an upper end of seal section 14 and securing a lower end of seal section 14 to an upper end of motor 15. A running tool (not shown) releasably engages a neck 22 on the upper end of pump 13, production fluids flowing out of neck 22, as in FIG. 1. The assembly 11 is then lowered with the running tool on a line (not shown), such as coiled tubing or cable, through production tubing 17 until the desired depth is reached. The running tool and coiled tubing are then retrieved. To limit erosion of the inner surface of production tubing 17, neck 22 may be of varying length, as shown by the broken line in FIG. 1. The next time that pump assembly 11 is retrieved for maintenance, it will be run in with a neck 22 of different length than the previous run. Assembly 11 passes through an orienting sleeve 23 and is rotated by engagement of a helical shoulder 25 which rotationally aligns assembly 11 to the required orientation for positioning within a no-go profile 27. The running tool may have a swivel, or other bearing, to allow assembly 11 to rotate during installation without rotating the coiled tubing.
Three wet-[0021] mateable power connectors 29 are used to provide electric power to motor 15. Outer connector assemblies 29 are affixed to production tubing 21 at 120-degree angular increments and may be located fully within annulus 18 or may slightly protrude within tubing 21. Each outer connector 29 is connected to one conductor of a power cable 31 that feeds electricity from a remote source to connector assemblies 29. Power cable 31 extends alongside and is strapped to tubing 17. Motor 15 has a set of inner connectors 33 located in a depending lower section 35 of motor 15 and positioned 120 degrees apart for mating with outer connector assemblies 29. Outer connector assembly 29 is shown engaged with inner connector 33.
[0022] Outer connector assemblies 29 may be hydraulically actuated, as described below and shown in FIGS. 3 through 5, and may be of the general design shown in U.S. Pat. No. 4,589,492 to Greiner, et al. It could also be of other types of retractable, wet-mateable design. Outer connector assemblies 29 are connected to hydraulic lines 37,39,41 and are located a vertical distance from the lower end of production tubing 17 that corresponds to the location of inner connector assemblies 33 when motor 15 is installed in production tubing 17. Lines 37, 39,41 are connected to a valve 43 that is electrically or hydraulically actuated. Valve 43 is connected to a hydraulic line 47 that provides pressure distributed by valve 43 to lines 37,39,41. An accumulator may also be mounted downhole with valve 43.
[0023] Inner connector assemblies 33 are located within the housing of motor 15 and are tangent to a vertical outer surface of motor 15 as seen in FIG. 5. When hydraulic pressure is applied to outer connector assemblies 29 by the position of valve 43, an outer insulator 45 in each connector 29 moves from a retracted position into engagement with inner connector assemblies 33. A connector pin 49 is then moved from a retracted position and through outer insulator 45 to engage an inner portion of inner connector assembly 33 for making an electrical connection insulated from seawater and production flow. To disconnect outer connector assemblies 29 from motor 15, hydraulic pressure is used to cause outer insulator 45 and connector pin 49 to move to their retracted positions. Because they are located in annulus 23, it is unnecessary to remove outer connector assemblies 29 and power cables 31 when removing pump assembly 11.
Each [0024] outer connector assembly 29 has a hydraulic cylinder 51 or housing mounted to the outer surface of production tubing 17. Outer insulator 45 extends radially through a passage 53 in production tubing 17, passage 53 intersecting the axis of production tubing 17 at a 90 degree angle. As shown in FIG. 3, outer insulator 45 is a resilient member that provides electrical insulation and has a convex, cylindrical sealing face 55 on its inner end. A passage 57 extends longitudinally through outer insulator 45 along the axis of outer insulator 45, and passage 57 terminates in a slit 59 at sealing face 55. Slit 59 remains in a closed position, as shown in FIG. 4, unless forced open.
A [0025] piston 61 is reciprocatingly carried in hydraulic cylinder 51, as shown in FIG. 3. Piston 61 is formed of electrical insulation material, such as phenolic, and reciprocates between a stop 63 and the inner end of hydraulic cylinder 51. Hydraulic line 39 supplies hydraulic pressure to move piston 61 between the inner and outer positions. Line 39 is connected to valve 43 which leads to a remote source of hydraulic pressure through line 47. The outer end of outer insulator 45 is secured to piston 61 for movement therewith. Piston 61 will move outer insulator 45 from an outer or retracted position, generally as shown in FIG. 3, to an inner or extended position as shown in FIG. 5. In the retracted position, sealing face 55 will be recessed within passage 53 and will not protrude past the wall of passage 53.
[0026] Male connector pin 49 is reciprocatingly carried within passage 57 of outer insulator 45. Connector pin 49 is a metal pin with a pointed tip 67 on its inner end. The outer end, as shown in FIG. 4, is rigidly secured to a piston 69 carried in hydraulic cylinder 51 which reciprocates between stops 63 and 73. Piston 69 is made of a electrically non-conductive material. An electrical insulator extends around a portion of connector pin 49, and will contact inner piston 61 when piston 69 is moved to the inner position in contact with stop 63. The movement of piston 69 causes connector pin 49 to move with respect to outer insulator 45 and extend past sealing face 55 through slit 59.
FIG. 4 shows an [0027] inner insulator 75 which is located within a cavity 77 in motor 15 and contains an inner connector 79. Inner connector 79 is preferably a female connector having a socket, a closed inner end, an open outer end and grooves or threads contained within. Insulator 75 and connector will remain permanently within motor 15.
A [0028] removable insulator 81 is also located in cavity 77 in motor 15. Insulator 81 has a cavity 83 therein that has an axis that coincides with the axis of inner connector 79 and, when pump assembly 11 is installed, with the axis of outer insulator passage 57. Cavity 83 contains a dielectric fluid 85, which is preferably a silicon gel that serves to prevent contact of electrically conductive liquids with the electrical connectors. Cavity 83 has a central enlarged area 87 of slightly larger diameter than the remaining portions of cavity 83.
A [0029] piston 89 is located in cavity 83, with its axis coinciding with the axis of inner connector 79. Piston 89 is made up of an insulating material that is soft enough to be penetrated by pointed tip 67 of connector pin 49. Piston 89 has a diameter that is approximately the same as the diameter of cavity 83, but smaller than the diameter of enlarged area 87, to allow dielectric fluid 85 to flow around piston 89 when it is moved toward the connector.
A metal, electrically-[0030] conductive sleeve 91 is secured to the inner side of piston 89 for movement therewith. Sleeve 91 has a closed end on its inner end. The outer diameter of sleeve 91 is approximately the inner diameter of inner connector 79. The inner diameter of sleeve 91 is approximately the outer diameter of connector pin 49. A flat rubber seal 93 extends across the outer face of piston 89 and is affixed within a recess 95 which is cylindrical and coaxial with cavity 83. Seal 93 can be pierced by tip 67 of connector pin 49. Recess 95 has a diameter the same as sealing face 55 of outer insulator 45.
In operation, [0031] outer connector assemblies 29 will be attached to the outer surface of production tubing 17, then tubing 17 will be installed in the well. Pistons 61, 69 will be in the retracted position. Sealing face 55 will be recessed within passage 53 in production tubing 17, and tip 67 of connector pin 49 will be recessed within passage 57.
Submersible pump assembly [0032] 11, along with swab cup 21, is lowered through tubing 17 into place in the well, landing on no-go 27. Valve 43 receives an electrical signal from the surface that causes hydraulic pressure to be supplied through line 39 to move piston 61 in each outer connector assembly 29 inward, with hydraulic fluid being returned to another line or to an accumulator. Each outer insulator 45 will move inward, and sealing face 55 will enter recess 95 and abut against seal 93. Well fluid within recess 95 will be purged from recess 95 by sealing face 55.
Then, another electrical signal is sent to [0033] valve 43 causing hydraulic pressure to be supplied through line 41 to push piston 69 inward. Connector pin 49 will extend through slit 59 (FIG. 4), pierce seal 93, and begin pushing piston 89 to the left. As piston 89 moves to the left, dielectric fluid 85 will squeeze into the interior of the connector and will flow around the edges of piston 89, coming into contact with the inner side of seal 93 and into contact with connector pin 49. Piston 89 will continue to move inward, with sleeve 91 entering the interior of connector 79, to establish electrical contact between inner connector 79 and sleeve 91. When sleeve 91 is unable to move any farther inward, connector pin 49 will pierce piston 89 and enter the interior of sleeve 91. This establishes electrical contact between connector pin 49 and cable 31 and prevents the entry of well fluid into motor 15. Stop 63 (FIG. 3) will prevent any farther movement inward of connector pin 49. Insulator 45 will be in abutment with piston 89, shielding connector pin 49 should leakage of well fluid into the housing occur. Pierced seal 93 assists in preventing the entry of well fluid. The coiled tubing is unlatched from pump assembly 11 and retrieved. When pump 13 is operating, well fluids flow upward through check valve 20 into the intake of pump 13 and are pumped up tubing 17. The three pin and insulator assemblies 45, 49 allow upward flow past them.
Submersible pump assemblies must be pulled periodically for maintenance and replacement. Coiled tubing with a retrieval tool is run back into the well and latched into the discharge neck [0034] 22. When removing pump assembly 11, the first step is to signal valve 43 to apply hydraulic pressure to line 39 (FIG. 3) to move connector pin 49 outward. Connector pin 49 will withdraw into passage 57, and slit 59 will close to prevent well fluid from entering passage 57. Then, hydraulic pressure is supplied to line 37 (FIG. 3) to cause piston 61 to move outward. This retracts outer insulator 45, removing sealing face 55 from recess 95 and from passage 53. The running tool will be lowered to connect with neck 22 of submersible pump assembly 11 and lift it through tubing 17 to the surface. Tubing 17, electrical connectors 29, and power cable 31 remain in place. During maintenance, insulator 81, sleeve 91, seal 93, and piston 89 are replaced with another unit filled with dielectric fluid 85. The same connector pins 49 and insulators 45 can be actuated to make the electrical connection.
In the event that sand or other sediments have built up around [0035] pump 13, it may be difficult to retrieve pump assembly 11 by pulling upward on the coiled tubing. If so, the operator may pump fluid down the coiled tubing, which flows down neck 22 and out of the bottom of pump 13. The fluid can not flow past check valve 20, therefore pressure builds up, tending to force pump 13 upward.
FIG. 2 shows an alternative embodiment of an electric, [0036] submersible pump assembly 12. The general method of installation and power connection is the same for the inverted configuration of pump assembly 12 shown in FIG. 2, but motor 15 is installed above seal section 14, and pump 13 is installed below seal section 14. Neck 22 is located on the upper end of motor 15 for grappling by the running tool (not shown). Connector assemblies 29, 33 are located a larger vertical distance from the lower end of production tubing 17. When pump assembly 11 is installed, a stinger 97 depending from the lower surface of pump 13 stabs through a flapper valve 99, the production flow passing into pump 13 through stinger 97. Flapper valve 99 is located in production tubing 17 below assembly 12 and is used to open and close tubing 17.
A second alternate embodiment of the invention is illustrated in FIGS. 6 and 7. FIG. 6 shows an [0037] assembly 101 comprised of pump 13, seal section 14, and motor 15 and assembled in the same orientation as assembly 11 in FIG. 1. Assembly 101 is installed within production tubing 17, which is within and generally coaxial with casing 16. As in the embodiments described above, a swab cup or packer 19 seals the lower portion of annulus 18 between tubing 17 and casing 16. Also, a check valve 20 may be installed near the lower portion of production tubing 17. Assembly 101 is suspended from head 103 by attaching the upper portion of pump 13 to the lower portion of head 103, head 103 being supported by no-go profile 104, a swab cup 105 being located above head 103. Head 103 has three inner power connectors 106 that selectively engage outer power connectors 107 to provide electricity to motor 15, connectors 106, 107 being positioned in 120-degree increments. Unlike the above-described embodiments, inner connectors 106 contain movable components (FIG. 7), and outer connectors 107 are static. Outer power connectors 107 are connected to power cable 31, which extends from a power supply on the surface. Power cable 109 is connected to connectors 106 and conducts power from head 103 to motor 15. Assembly 101 is lowered into position on coiled tubing 111, which provides hydraulic pressure to operate inner power connectors 106.
FIG. 7 illustrates details of one embodiment of [0038] power connectors 106, 107. Each inner power connector 106 comprises an inner insulator 113 and a male connector pin 115. Insulator 113 and pin 115 are connected to pistons 117 and 119, respectively, which are reciprocatingly carried within cylinder 121 of connector 106. Pistons 117, 119 and insulator 113 are formed of electrical insulation material in this embodiment. A slit 123 in insulator 113 allows pin 115 to pass through the outer end of insulator 113. Pin 115 has a pointed outer end 125 and an inner end 127 that is connected to power cable 129. Three ports 131, 133, 135 extend upward through the upper portion of head 103 for providing hydraulic fluid to move pistons 117, 119 within cylinder 121. Ports 131, 133, and 135 align with and sealingly engage passages 137, 139, and 141, respectively, when a running tool 143 is attached to head 103 during installation of assembly 101. Each port 131, 133, 135 has a coupling 132 that sealingly engages a coupling 134 on one of passages 137, 139, 141. Couplings 132, 134 are of conventional design and preferably contain check valves to prevent leakage of fluid pressure and to prevent well fluids from entering head 103 or running tool 143. In FIG. 7, running tool 143 is shown detached from head 103.
Running [0039] tool 143, which is not part of this application, has a latch member that is hydraulically actuated to release pump assembly 101 (FIG. 6) after it has landed. A retrieval tool has the same arrangement. One type of running tool has a chamber containing hydraulic fluid and a piston. The piston has one side in contact with the hydraulic fluid and the other side in contact with water pumped down coiled tubing 111 for applying pressure to the chamber. An output passage from the chamber leads to a valve section that selectively applies the pressure to passages 137, 139, 141 and a port leading to the unlatch mechanism. The valve section has a selector that shifts from one position to another in response to axial manipulation of the string of coiled tubing 111.
Other types of running and retrieval tools are feasible, such as ones employing a separate hydraulic and/or electric line, run with coiled tubing [0040] 111. The hydraulic and electric lines could be used to supply pressure to passages 137, 139, 141 and operate the valves.
[0041] Outer power connector 107 extends through hole 145 in tubing 17 at a position that aligns outer connector 107 and inner connector 106. Insulator 147 is located within hole 145, filling the outer portion of hole 145, a recess remaining in the inner portion of hole 145. Insulator 147 and hole 145 each have the same diameter as inner insulator 113. A slit 149 extends through insulator 147, leading to receptacle 151. Receptacle 151 is attached to power cable 31 and is sized to receive pointed end 125 of pin 115.
In operation, casing [0042] 16 is cemented within a borehole. Outer connectors 107 are installed in tubing 17, then tubing 17 is installed within casing 16. Running tool 143 is attached to coiled tubing 111 (FIG. 6) and head 103 for lowering assembly 101 into the well, ports 131, 133, 135 being sealingly engaged with passages 137, 139, 141. Pistons 117 and 119 are retracted to their innermost positions, the outer end of insulator 113 being nearly flush with the outer surface of head 103 and pin 115 being located fully within insulator 113. Slit 123 is closed to prevent well fluids from entering insulator 113, and slit 149 is closed to prevent well fluids from entering annulus 18. Assembly 101 is lowered within tubing 17 until head 103 rests on no-go profile 104 (FIG. 6).
After landing, hydraulic pressure is provided by pumping water down coiled tubing [0043] 111, which, due to the valves, forces hydraulic fluid through port 133 to force insulator 113 outward toward connector 107. The outer end of insulator 113 contacts the inner surface of insulator 147 of connector 107, slit 123 aligning with slit 149 and well fluids being displaced from hole 145.
The operator then shifts the running tool valves by stroking the coiled tubing. Hydraulic pressure is then applied to the inner surface of [0044] piston 119 through passage 141 and port 135 by pumping water down coiled tubing 111, moving pin 115 outward. Pointed end 125 moves through slit 123 and through slit 149 and enters receptacle 151. Pin 115 carries electricity from power cable 31 to power cable 129, and cable 129 conducts electricity to cable 109, cable 109 conducting electricity to motor 15. When electricity is supplied to motor 15, motor 15 rotates to turn pump 13 to pump well fluids upward. After connectors 106 are engaged with connectors 107, running tool 143 is disconnected from head 103 and removed from within tubing 17. To release, the operator strokes coiled tubing 111 again and then applies pressure through coiled tubing 111. This forces hydraulic fluid to the latching mechanism and release from pump assembly 101. To remove assembly 101 from within tubing 17, running tool 143 is reattached to head 103, and the installation process is reversed to disengage pin 115 and insulator 113 from connector 107.
A third alternate embodiment of the invention is illustrated in FIG. 8. Like those described above, [0045] assembly 151 comprises pump 13, a motor (not shown), and a seal section not shown). Tubing 17 is located within casing 16, and power cable 31 is located within annulus 18. Connector arm 153 is mounted to the inner surface of tubing 17 and connects to power cable 31 through tubing 17. Electrical wires (not shown) within arm 153 conduct electricity from power cable 31 to three bands 155 located on stab 157. Stab extends upward from connector arm 153 and has a pointed or rounded upper end. Bands 155 are circumferential rings formed from metal, or other conductive materials, and are axially spaced apart from each other along stab 157. Though assembly 151 is illustrated with pump 13 at the lower end of assembly 151, pump 13 may be located at the upper end of assembly 151 with the motor being at the lower end.
[0046] Assembly 151 also comprises a motor connector 159 located below pump 13 and used for connecting a power cable 161 to bands 155 on stab 157. Motor connector 159 contains contacts 163, which are preferably spring-biased towards the center of motor connector 159, for contacting bands 155 when stab 157 is inserted into motor connector 159. Contacts 163 protrude sealingly through inner wall 165 and are axially spaced apart by the same lengths as bands 155. Contacts 163 are connected within motor connector 159 to power cable 161 by wires 167. Power cable 161 extends upward to the motor, providing electricity for operating the motor. A wiper 169 is located in the lower end of motor connector 159 for wiping well fluids from stab 157 as stab 157 is inserted. In an alternative embodiment (not shown), motor connector 159 may be located within the motor when the motor is located at the lower end of assembly 151.
In operation, [0047] assembly 151 is constructed with motor connector 159 connected by power cable 161 to the motor, motor connector 159 being located at the bottom of assembly 151. Connector arm 153 is mounted to production tubing 17, and tubing 17 is installed within casing 16. Assembly 151 is then lowered into production tubing 17 on a wireline or by other suitable means until stab 157 enters motor connector 159. The weight of assembly 151 forces motor connector 159 onto stab 157, stab passing through wiper 169 and forcing contacts 163 outward. Assembly moves downward until fully seated on stab 157 and connector arm 153. When fully seated, contacts 163 are aligned with and contact bands 155. The operator provides electricity through power cable 31, the electricity flowing through connector arm 153 to bands 155, then through contacts 163 and wires 167, then through power cable 161 to the motor. To remove assembly 151 from within tubing 17, assembly is connected to a line and pull upwards to disengage motor connector 159 from stab 157.
The advantages of using the present invention include the ability to retrieve a submersible pump assembly without the need for withdrawing the power cable, too. The cable is permanently deployed in the annulus surrounding the string of production tubing and is selectively connected to the pump assembly using wet-mateable electrical connectors. By permanently deploying the power cable, the difficulty of removing the pump assembly and the wear and tear on the cable are both minimized. [0048]
While the invention has been shown in only two of its forms, it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes without departing from the scope of the invention. For example, only one power connector or band may be needed when using DC power, the motor being grounded through the coiled tubing or production tubing. Power connectors may be operated by means other than hydraulic pressure, for example, by electrical, pneumatic, or mechanical means. Also, various means of seating the motor connector on the stab are available, including hydraulic or electric actuators carried in the motor connector. [0049]

Claims

We claim:

1. A well pumping apparatus, comprising:

a string of production tubing located within a casing, defining a tubing annulus between the tubing and the casing;

a submersible pump assembly having a pump, an electric motor, and an electrical motor connector, the submersible pump assembly being dimensioned for lowering and retrieving through the tubing;

a power cable located in the tubing annulus; and

a power-cable connector mounted to the tubing and connected to the power cable, the power-cable connector making electrical contact with the motor connector when the submersible pump assembly motor is landed in the tubing

2. The apparatus of claim 1, wherein:

the power-cable connector comprises an arm extending inward from an inner surface of the production tubing and a stab extending upward from the arm, the stab having at least one conductor on an outer surface; and

the motor connector comprises a receptacle for receiving the stab, the receptacle having at least one contact for engaging the conductor on the stab.

3. The apparatus of claim 2, wherein:

the stab comprises three conductors; and

the receptacle comprises three contacts.

4. The apparatus of claim 1, wherein:

the power-cable connector comprises three conductors radially arrayed about an axis of the tubing in 120-degree increments; and

the motor connector comprises three conductors radially arrayed about an axis of the submersible pump assembly in 120-degree increments.

5. The apparatus of claim 1, wherein:

the motor connector comprises at least one receptacle located on the submersible pump assembly; and

the cable connector comprises at least one pin mounted to the tubing, each pin being selectively moved from a retracted position into engagement with one receptacle.

6. The apparatus of claim 1, wherein:

the motor connector comprises a plurality of receptacles located on the submersible pump assembly; and the cable connector comprises a plurality of pins carried by hydraulic cylinders mounted to the tubing, the hydraulic cylinders moving the pins from a retracted position into engagement with the receptacles.

7. The apparatus of claim 1, wherein:

the cable connector comprises a plurality of receptacles located on the tubing; and

the motor connector comprises a plurality of pins mounted to the submersible pump assembly selectively moved from a retracted position into engagement with the receptacles.

8. The apparatus of claim 1, further comprising:

an orienting guide mounted to the tubing for rotating the submersible pump assembly to a selected orientation while landing in the tubing.

9. The apparatus of claim 1, wherein:

the motor connector comprises a plurality of receptacles located on a connector assembly extending downward from the motor.

10. The apparatus of claim 1, wherein:

the motor connector comprises a plurality of pins mounted to the submersible pump assembly selectively moved from a retracted position into engagement with the receptacles, the motor connector being located above the pump; and further comprising

a lead extending from the motor connector to the motor for conducting electricity from the motor connector to the motor.

11. The apparatus of claim 1, further comprising:

a running tool adapted to be secured to a running line and to the submersible pump assembly for lowering the submersible pump assembly into the tubing, the running tool being releasable from the submersible pump assembly for retrieving the running line and running tool after landing the submersible pump assembly.

12. A well pump apparatus, comprising:

a submersible pump assembly having a pump, an electric motor, and an electrical receptacle assembly, the pump and motor being dimensioned for lowering and retrieving through a string of production tubing;

a power cable adapted to be strapped to an exterior of the production tubing; and

a connector-pin assembly adapted to be mounted to the tubing and connected to a lower end of the power cable for providing electricity to the motor, the pin assembly having a pin that is moved between a retracted position and an engaged position in engagement with the receptacle assembly,

13. The apparatus of claim 12, further comprising:

a hydraulic cylinder for moving the pin between the retracted and engaged positions.

14. The apparatus of claim 12, wherein:

the electrical receptacle assembly comprises three receptacles spaced 120 degrees apart about an axis of the motor; and

the pin assembly comprises three pins adapted to be radially arrayed in 120-degree increments about an axis of the tubing.

15. The apparatus of claim 12, further comprising:

an orienting guide adapted to be mounted to the tubing for rotating the pump and motor to a selected orientation while landing in the tubing.

16. The apparatus of claim 12, wherein:

the electrical receptacle assembly is mounted to a connector depending from a bottom of the motor.

17. The apparatus of claim 12, further comprising:

18. A method of installing a pumping apparatus in a well, the method comprising:

(a) mounting a power-cable connector and a power cable to a string of tubing and lowering the tubing into the well;

(b) providing a submersible pump assembly having a pump, an electric motor, and an electrical motor connector; then

(c) lowering the submersible pump assembly through the tubing; then

(d) engaging the power-cable connector with the motor connector when the motor is landed in the tubing

19. The method of claim 18, wherein:

the power-cable connector comprises an arm extending inward from an inner surface of the tubing and a stab extending upward from the arm, the stab having at least one conductor on an outer surface;

the motor connector comprises a receptacle for receiving the stab, the receptacle having at least one contact for engaging the conductor on the stab; and

in step (d), inserting the stab into the receptacle, each conductor engaging one contact.

20. The method of claim 18, wherein:

the motor connector comprises a at least one receptacle located on the submersible pump assembly;

the power-cable connector comprises at least one pin mounted to the tubing; and

in step (d), selectively moving each pin from a retracted position into engagement with one receptacle.

21. The method of claim 18, wherein:

the motor connector comprise a plurality of receptacles located on the submersible pump assembly;

the power-cable connector comprises a plurality of pins carried by hydraulic cylinders mounted to the tubing; and

step (d) comprises supplying fluid pressure to the hydraulic cylinders to move the pins from a retracted position into engagement with the receptacles.

22. The method of claim 18, wherein:

the motor connector comprises a plurality of pins located on the submersible pump assembly;

the power-cable connector comprises a plurality of receptacles; and

in step (d), selectively moving the pins from a retracted position into engagement with the receptacles.

23. The method of claim 18, wherein:

step (c) comprises lowering the submersible pump assembly on a line; and the method further comprising

releasing the line from the submersible pump assembly and retrieving the line.

24. A method of installing a pumping apparatus in a well, the method comprising:

(c) lowering the submersible pump assembly through the tubing on a running line; then

(d) moving pins contained in one of the power-cable connector and the motor connector into engagement with the other of the power-cable connector and the motor connector when the motor is landed in the tubing; then

(e) releasing the running line from the submersible pump assembly and retrieving the running line.

25. The method of claim 24, wherein:

step (b) further comprises providing the submersible pump assembly with a first discharge tube of a first selected length above the submersible pump assembly; the method further comprising

retrieving the submersible pump assembly through the tubing for maintenance and replacing the first discharge tube with a second discharge tube of a second selected length that differs from the first selected length; and

reinstalling the submersible pump assembly in the tubing.

26. The method of claim 24, wherein:

step (c) comprises installing a swab cup above the submersible pump assembly, the swab cup restricting the upward flow of fluid in the production tubing past the swab cup and preventing fluid from flowing downward past the swab cup; and

installing a check valve in the tubing below the submersible pump assembly the check valve allowing fluid to flow upward through the check valve and preventing downward flow through the check valve.

27. The method of claim 26, further comprising:

reattaching the running line to the submersible pump assembly for retrieving the submersible pump assembly; and

pumping fluid downward through the running line and through the pump to cause a fluid pressure between the swab cup and the check valve, the pressure applying upward force on the submersible pump assembly to assist in retrieval.