U.S. patent application number 09/969230 was filed with the patent office on 2002-05-02 for novel completion method for rigless intervention where power cable is permanently deployed.
Invention is credited to Brookbank, Earl B., Neuroth, David H., Shaw, Christopher K..
Application Number | 20020050361 09/969230 |
Document ID | / |
Family ID | 26929821 |
Filed Date | 2002-05-02 |
United States Patent
Application |
20020050361 |
Kind Code |
A1 |
Shaw, Christopher K. ; et
al. |
May 2, 2002 |
Novel completion method for rigless intervention where power cable
is permanently deployed
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.
Inventors: |
Shaw, Christopher K.;
(Damascus, SY) ; Brookbank, Earl B.; (Claremore,
OK) ; Neuroth, David H.; (Claremore, OK) |
Correspondence
Address: |
Bracewell & Patterson, LLP
Suite 1600
201 Main Street
Fort Worth
TX
76102
US
|
Family ID: |
26929821 |
Appl. No.: |
09/969230 |
Filed: |
October 1, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60236485 |
Sep 29, 2000 |
|
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|
Current U.S.
Class: |
166/380 ;
166/105 |
Current CPC
Class: |
E21B 43/128 20130101;
H01R 13/523 20130101 |
Class at
Publication: |
166/380 ;
166/105 |
International
Class: |
E21B 043/00 |
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: 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.
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: (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 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.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Applicant's copending
U.S. provisional application, Serial No. 60/236,485, filed on Sep.
29, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to downhole installations
and relates specifically to rigless interventions using electric
motors and wet-mateable electrical connections.
[0004] 2. Description of the Prior Art
[0005] 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.
[0006] 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
[0007] 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.
[0008] 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.
[0009] 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
[0010] 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.
[0011] 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.
[0012] 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.
[0013] FIG. 3 is a cross-sectional view of electrical connecting
assemblies for use with the submersible-pump assemblies of FIG. 1
or FIG. 2.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] FIG. 7 is a cross-sectional view of electrical connecting
assemblies for use with the submersible-pump assembly of FIG.
6.
[0018] 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.
DETAILED DESCRIPTION OF THE INVENTION
[0019] FIG. 1 shows an electric, submersible-pump assembly 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.
[0020] Pump assembly 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.
[0021] Three wet-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.
[0024] Each 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.
[0025] A 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.
[0027] FIG. 4 shows an 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.
[0028] A 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.
[0029] A 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.
[0030] A metal, electrically-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.
[0031] In operation, 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.
[0032] Submersible pump assembly 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.
[0033] Then, another electrical signal is sent to 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.
[0034] 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 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.
[0035] In the event that sand or other sediments have built up
around 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.
[0036] FIG. 2 shows an alternative embodiment of an electric,
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.
[0037] A second alternate embodiment of the invention is
illustrated in FIGS. 6 and 7. FIG. 6 shows an 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.
[0038] FIG. 7 illustrates details of one embodiment of 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.
[0039] Running 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.
[0040] Other types of running and retrieval tools are feasible,
such as ones employing a separate hydraulic and/or electric line,
run with coiled tubing 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.
[0042] In operation, casing 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).
[0043] After landing, hydraulic pressure is provided by pumping
water down coiled tubing 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.
[0044] The operator then shifts the running tool valves by stroking
the coiled tubing. Hydraulic pressure is then applied to the inner
surface of 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.
[0045] A third alternate embodiment of the invention is illustrated
in FIG. 8. Like those described above, 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.
[0047] In operation, 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.
[0048] 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.
[0049] 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.
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