Information
-
Patent Grant
-
6332499
-
Patent Number
6,332,499
-
Date Filed
Tuesday, November 23, 199925 years ago
-
Date Issued
Tuesday, December 25, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Fletcher, Yoder & Van Someren
-
CPC
-
US Classifications
Field of Search
US
- 166 380
- 166 385
- 166 387
- 166 664
- 166 651
- 166 654
- 166 2426
- 439 194
- 439 195
- 439 191
-
International Classifications
-
Abstract
A connector for use in a deployment system able to deploy and power a device, such as an electric submergible pumping system, in a well. The connector includes pluggable ends that permit connection adjacent segments, each having an outer section of tubing and an internal power cable. Each connector includes a tubing connector portion and a power cable connector portion that permit pluggable connection of sequential tubing segments when deploying a device or system downhole.
Description
FIELD OF THE INVENTION
The present invention relates generally to a system for deploying well-related equipment, such as electric submergible pumping systems, and particularly to a connector that permits secure connection of segments of combined external deployment tubing and internal power cable.
BACKGROUND OF THE INVENTION
A variety of systems are used for deploying equipment used in the production of fluids, such as oil, from producing wells. For example, tubing has commonly been used for the deployment of downhole equipment. Electric submergible pumping systems, for instance, may be deployed by appropriate deployment tubing to a desired location within a wellbore. Depending on the application, the production fluid is produced either through the center of the tubing or through the annulus formed between the tubing and the wellbore casing.
When deploying systems, such as electric submergible pumping systems, it is necessary to provide power to the system. Accordingly, a power cable is connected between a power supply at the surface and a submergible electric motor of the electric submergible pumping system. The power cable generally is either tied to the outside of the tubing or routed through the center of the tubing. For example, if the production fluid is produced through the annulus formed around the deployment tubing, it is convenient to provide power cable through the center of the tubing.
One type of commonly used tubing is coiled tubing. Coiled tubing may be transported in rolls that are unrolled during deployment of the downhole system for relatively rapid and convenient deployment of the system, e.g. an electric submergible pumping system. For certain applications, a power cable is disposed in the center of the coiled tubing. by way of example, Reda of Bartlesville, Okla., a division of Schlumberger Corporation, manufactures REDACoil™, a product in which power cable is prepackaged within coiled tubing. Repairing or connecting lengths of coiled tubing with internal power cable can be difficult, particularly when the splice is made in the field.
Also, the coiled tubing and internal power cable generally are formed in the lengths necessary to accommodate deployment of the electric submergible pumping system to a desired location within a wellbore. However, extremely long lengths of tubing and power cable can be difficult to handle, and the equipment used to deploy downhole systems may be limited to a given length of tubing.
In certain applications, e.g. deep wells, and in certain situations in which the deployment tubing requires repair, it would be advantageous to have a connector system that permitted a relatively simple combination of independent segments of tubing, particularly coiled tubing having a combined power cable.
SUMMARY OF THE INVENTION
The present invention features a connector system for connecting sections of tubing used in deploying a downhole device for production of fluid from a well. The connector system includes a tubing connector having an upper nipple section sized for receipt in a first tubing end. The tubing connector also includes a lower nipple section sized for receipt in a second tubing end. The tubing connector also includes a hollow interior for receiving an electrical feed-through. The electrical feed-through has a first connection end, a second connection end and a plurality of conductors extending between the first and the second connection ends. The tubing connector and the electrical feed-through provide for ready connection of segments in a modular deployment system.
According to another aspect of the invention, a coiled tubing connection system is provided. The system includes a first segment of coiled tubing having a first connector end and a first hollow interior. The system also includes a first power cable disposed in the hollow interior and having a first plug proximate the first connector end. A second segment of coiled tubing has a second connector end and a second hollow interior. Also, a second power cable is disposed in the second hollow interior and has a plug proximate the second connector end. The system further includes a coiled tubing connector having a housing sized to selectively engage the first connector end and the second connector end. The coiled tubing connector further includes an internal plug assembly positioned to conductively engage the first plug and the second plug when the first and second connector ends are engaged with the coiled tubing connector.
According to another aspect of the invention, a connector is provided for use in wellbore environments to connect segments of a tubing-style deployment system. The connector includes an outer housing having a pair of connection ends positioned to connect two consecutive sections of tubing in a wellbore. Additionally, the connector includes an internal electrical connector assembly disposed within the outer housing to electrically couple a power cable deployed within the two consecutive sections of tubing.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and
FIG. 1
is a front elevational view of an exemplary deployment system, deploying an electric submergible pumping system, according to a preferred embodiment of the present invention;
FIG. 2
is cross-sectional view taken generally along the axis of a portion of the connector system utilized in connecting sequential segments of deployment tubing having internal power cable;
FIG. 3
is a cross-sectional view similar to that of
FIG. 2
but showing an internal electrical feed-through, according to one embodiment of the present invention;
FIG. 4
is a partial cross-sectional view showing the connector system components of
FIG. 3
connecting sequential segments of coiled tubing;
FIG. 5
is a partial cross-sectional view of the electrical feed-through showing an exemplary plug portion;
FIG. 6
is a top view of the plug portion illustrated in
FIG. 5
;
FIG. 7
is a partial cross-sectional view of the end of a tubing segment showing the plug portion designed for selective engagement with the plug portion illustrated in
FIGS. 5 and 6
; and
FIG. 8
is a bottom view of the tubing segment plug illustrated in FIG.
7
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring generally to
FIG. 1
, an exemplary deployment system
10
is illustrated in a wellbore environment. Deployment system
10
is attached to an electric submergible pumping system
12
and preferably a bottom intake system. Deployment system
10
can be utilized in the deployment of a wide variety of devices or systems, but the unique design of deployment system
10
is particularly amenable to deployment of electric submergible pumping systems
12
.
A typical bottom intake pumping system
12
may comprise a variety of components depending on the particular application or environment in which it is used. Typically, system
12
includes at least a submergible pump
14
, a pump intake
15
, a submergible motor
16
, a motor protector
17
and a packer assembly
18
. However, a variety of other or additional components can be utilized in the system.
For example, system
12
may include a thrust section
19
and a connector
20
by which submergible pumping system
12
is coupled to deployment system
10
. Also, a variety of component types may be utilized. For instance, an exemplary motor
16
is a three-phase, induction-type motor, and an exemplary pump
14
is a multi-stage centrifugal pump. In this type of system, submergible pump
14
draws wellbore fluid through pump intake
15
and discharges it through a packer discharge head
21
above the packer assembly
18
into the annulus formed about deployment system
10
. A variety of packer assemblies also may be utilized, such as a mechanically set packer or a hydraulic packer, such as the Camco HRP-1-SP Hydraulic Set Packer available through Camco of Houston, Tex.
In the example illustrated, system
12
is designed for deployment in a well
22
within a geological formation
24
that contains desirable production fluids, such as petroleum. In a typical application, a wellbore
26
is drilled and lined with a wellbore casing
28
. Wellbore casing
28
may include a plurality of openings
30
, often called perforations, through which production fluids flow into wellbore
26
.
Although deployment system
10
may have a variety of forms and configurations, it typically comprises tubing, and preferably two or more sections of coiled tubing
32
. A power cable
34
is disposed within a hollow interior
36
of the tubing
32
. The power cable
34
is supported within tubing
32
by appropriate anchors, buoyancy fluid or other means. Power cable
34
often includes at least three conductors
33
surrounded by one or more layers of insulation
35
and an outer protective armor
37
.
As illustrated, deployment system
10
comprises two or more segments
38
connected by one or more connector systems
40
. Each segment
38
includes an outer tube, e.g. a section of coiled tubing
32
, and a combined power cable, such as an internal power cable
34
.
Referring generally to
FIG. 2
, a portion of one of the connector systems
40
is illustrated.
FIG. 2
shows a tubing connector
42
that permits the secure connection of the tubing
32
of one segment
38
to the tubing of the next sequential tubing segment
38
. Tubing connector
42
includes a pair of nipples or inserts, referred to as an upper insert
44
and a lower insert
46
, sized for insertion into the hollow tubing interiors of adjacent segments
38
. Tubing connector
42
also includes an expanded region
48
disposed between upper insert
44
and lower insert
46
. Expanded region
48
provides an upper abutment surface
50
and a lower abutment surface
52
. Upper and lower abutment surfaces
50
,
52
provide a stop against which the external tubing
32
of adjacent segments
38
abut when slid over cylindrical upper insert
44
and cylindrical lower insert
46
.
Preferably, each tubing connector
42
includes one or more seals disposed to prevent liquid flow between tubing connector
42
and an attached deployment system segment
38
. In the illustrated embodiment, upper insert
44
includes a pair of annular grooves
54
formed in an external surface
56
. A sealing member
58
, such as an elastomeric seal, is disposed in each groove
54
to encircle upper insert
44
and to provide a liquid-tight seal between upper insert
44
and a connected segment
38
.
Similarly, lower insert
46
includes a pair of annular grooves
60
formed in an exterior surface
62
. A sealing member
64
, such as an elastomeric seal, is disposed in each annular groove. Seal members
64
provide a liquid-tight seal between lower insert
46
and a connected segment
38
. It should be noted that the actual number of seal members
58
,
64
may be one or more depending on such factors as tubing connector design and application of the overall deployment system.
Additionally, a retention system
66
is used to ensure that segments
38
remain connected to tubing connector
42
during deployment and use of downhole system
12
. In the illustrated embodiment, retention system
66
includes a plurality of dimples
68
formed in exterior surface
56
of upper insert
44
and exterior surface
62
of lower insert
46
. Dimples
68
permit the slight deformation of the coiled tubing
32
of each segment
38
once attached to tubing connector
42
. The sidewall of each section of tubing
32
is appropriately deformed in a radially inward direction such that it deforms into dimples
68
(see
FIG. 4
) to prevent the attached segment
38
from inadvertently sliding off the upper insert
44
or lower insert
56
to which it is attached.
Tubing connector
42
also includes a hollow interior
70
that preferably extends generally along a longitudinal axis
72
. Hollow interior
70
is defined by an interior wall surface
74
that extends between an upper opening
76
and a lower opening
78
.
Hollow interior
70
is sized to receive an electrical feed-through
80
, as illustrated in FIG.
3
. Feed-through
80
is designed for connection to the internal power cable
34
included in each segment
38
. Thus, each connector system
40
includes a tubing connector
42
and an electrical feed-through
80
to couple sequential segments
38
both mechanically and electrically.
In the illustrated embodiment, feed-through
80
includes an outer housing
82
that may be formed from a suitable metal or plastic. Outer housing
82
includes a midsection
84
, an upper plug portion
86
and a lower plug portion
88
. In the exemplary embodiment, midsection
84
has a larger diameter than upper plug portion
86
or lower plug portion
88
. The diameter of midsection
84
may be slightly less than the diameter of interior surface
74
to permit feed-through
80
to be slid into the center of hollow interior
70
. Additionally, one or more annular seals, such as O rings, may be disposed about midsection
84
to form a seal between feed-through
80
and interior surface
74
of tubing connector
42
.
Preferably, upper plug portion
86
and lower plug portion
88
are generally cylindrical in shape and have a smaller diameter than midsection
84
. In the illustrated design, the smaller diameter of the plug portions facilitates the selective, pluggable connection with sections of power cable disposed within adjacent segments
38
. Specifically, the smaller diameter of upper plug portion
86
provides for the formation of an annular space
92
between upper plug portion
86
and interior surface
74
. Similarly, the size and shape of lower plug portion
88
provides for the formation of an annular space
94
between plug portion
88
and interior surface
74
. Additionally, each plug portion
86
,
88
may include regions that facilitate the secure connection between feed-through
80
and adjacent power cable sections. For example, each plug portion may include one or more regions of ridges
96
or other surface abnormalities to help maintain secure mechanical and electrical connection.
Referring generally to
FIG. 4
, an entire exemplary connector system
40
is illustrated. Each segment
38
includes an outer section of tubing
32
, preferably coiled tubing, and an internal power cable section
34
. Each modular segment includes a segment connector end
100
designed for both mechanical and electrical connection into connector system
40
.
As illustrated, the coiled tubing
32
of each connector end
100
has an interior surface
102
of appropriate size to permit sliding engagement with either upper insert
44
or lower insert
46
. Preferably, a retention system is used to maintain secure connection between tubing segment
38
and either upper insert
44
or lower insert
46
. In the exemplary embodiment, a plurality of tubing dimples
104
are formed in the tubing sidewall of each tubing segment
38
such that the tubing material, typically steel, is deformed into dimples
68
of tubing connector
42
.
Additionally, each section connector end
100
includes an electrical connector, such as a plug
106
, that is electrically connected with the corresponding power cable section
34
. In the exemplary embodiment, each plug
106
is sized for insertion into hollow interior
70
to achieve mating engagement with the corresponding plug portion
86
or
88
. Preferably, the length of plug
106
is selected to permit an end of tubing
32
for each segment
38
to lie proximate or against the corresponding abutment surface
50
or
52
when the plug
106
is engaged with its corresponding plug portion of feed-through
80
.
Although a variety of plug styles may be selected, the illustrated plug is sized and designed such that it can slide into hollow interior
70
and along annular space
92
or
94
as it engages upper plug portion
86
or lower plug portion
88
, respectively. Generally, each plug
106
is disposed adjacent midsection
84
when fully engaged.
It is preferred that each plug
106
be mounted securely in its corresponding section connector end
100
. Accordingly, each plug
106
may be connected to tubing
32
by a connection block
108
. Connection block
108
may have a variety of forms, including epoxy blocks or metallic blocks that are mounted in place via appropriate notches and grooves, ring clips disposed above and beneath the connection block, set screws extending through tubing
32
, etc. In some applications, it also may be desirable to seal connection block
108
against interior surface
102
of tubing
32
by appropriate O rings or other seals (not shown). By forming an appropriate seal between each connection block
108
and tubing
32
, the interior of each tubing section
32
, intermediate connection blocks
108
, can be filled with a buoyancy fluid
110
having a specific gravity selected to support power cable
34
within tubing
32
. However, a variety of mechanical power cable anchors and supports can be utilized to support the power cable, as with conventional systems.
A variety of connectors, including other types of plug connectors, can be used for forming the connection between power cable
44
and electrical feed-through
80
to ensure, for example, power delivery to submergible motor
18
. In a typical power delivery system, the connectors, e.g. plugs, must be designed to facilitate the transfer of three-phase power, typically through three or more conductors. An exemplary plug connector system is illustrated in
FIGS. 5 through 8
.
Referring first to
FIGS. 5 and 6
, an exemplary upper plug portion
86
is illustrated. It should be noted that the description of upper plug portion
86
also applies to lower plug portion
88
. As illustrated, upper plug portion
86
is a female plug having an exterior defined by outer housing
82
. Within outer housing
82
, plug portion
86
includes an inner support material
112
, such as an insulative plastic plug material. The support material
112
may be connected to housing
82
by appropriate tabs
114
designed to engage corresponding features formed in housing
82
. Additionally, support material
112
is designed to support a plurality, e.g. three, conductive receptacles
116
.
Each conductive receptacle
116
preferably includes a tapered inlet region
118
to facilitate the insertion of corresponding conductive prongs, as will be described below. Each tapered inlet
118
is formed from a conductive material that is typically a conductive metallic material. Furthermore, each tapered inlet
118
is connected to a conductor
120
that passes longitudinally through feed-through
80
to corresponding conductive receptacles in lower plug portion
88
.
Referring now to
FIGS. 7 and 8
, an exemplary plug
106
is illustrated as designed for mating engagement with a corresponding plug portion
86
or
88
of electric feed-through
80
. As illustrated, each plug is defined by a plug housing
122
having an annular end portion
124
defining a hollow end region
126
. A plurality of prongs
128
extend into hollow end region
126
to form a male plug portion designed for mating engagement with, for example, upper plug portion
86
.
In the specific example illustrated, there are three prongs
128
properly arranged to slide into corresponding conductive receptacles
116
when the tubing segment
38
is inserted into engagement with upper insert
44
or lower insert
46
. Prongs
128
typically are metallic prongs electrically connected to corresponding conductors
130
that extend through plug
106
and power cable
34
.
During coupling of adjacent modular segments
38
, prongs
128
are slid into receptacles
116
as annular end portion
124
slides into either annular space
92
or
94
. Simultaneously, insert
44
or
46
slides into an annulus
132
formed between plug
106
and tubing
32
at section connector end
100
. Thus, a plurality of modular segments can be connected and/or disconnected relatively simply and easily by inserting (or removing) the connector inserts
44
,
46
into adjacent section connector ends
100
of sequential modular segments.
The use of a connector system
40
permits ready repair of coiled tubing, combination of multiple lengths of tubing, and the manufacture of standardized lengths of coiled tubing segments that may be mounted on a wider variety of deployment equipment. The modular coiled tubing segments simply can be plugged together to deploy a given system, such as electric submergible pumping system
12
, to a desired depth within the wellbore.
It will be understood that the foregoing description is of preferred exemplary embodiments of this invention, and that the invention is not limited to the specific forms shown. For example, a variety of electrical connectors can be utilized; various retention systems may be used to maintain a solid connection between modular tubing sections and connectors during deployment; the male and female plugs can be reversed; a variety of materials may be used in forming the electrical feed-through and the tubing connector; and the components may be made in a variety of sizes and diameters. Additionally, locational language, such as “upper” and “lower”, is used in the description above is only to facilitate explanation of the illustrated embodiment, and it should not be construed as limiting the scope of the invention. These and other modifications may be made in the design and arrangement of the elements without departing from the scope of the invention as expressed in the appended claims.
Claims
- 1. A connector system for connecting sections of tubing used in deploying a device for production of a fluid, comprising:a tubing connector having an upper nipple section sized for receipt in a first tubing end and a lower nipple section sized for receipt in a second tubing end, the tubing connector having a hollow interior; and an electrical feed-through disposed in the hollow interior, the electrical feed-through having a first connection end, a second connection end, and a plurality of conductors extending between the first and the second connection ends.
- 2. The connector system as recited in claim 1, wherein the tubing connector includes an expanded midsection having a first abutment surface against which the first tubing end may abut and a second abutment surface against which the second tubing end may abut.
- 3. The connector system as recited in claim 2, further comprising a plurality of external seals disposed about the tubing connector.
- 4. The connector system as recited in claim 1, wherein the first connection end comprises a first plug portion having a plurality of receptacles, each receptacle being coupled to a corresponding conductor of the plurality of conductors.
- 5. The connector system as recited in claim 3, further comprising a plurality of internal seals disposed between the tubing connector and the electrical feed-through.
- 6. The connector system as recited in claim 4, wherein the second connection end comprises a second plug portion having a plurality of receptacles, each receptacle being coupled to a corresponding conductor of the plurality of conductors.
- 7. The connector system as recited in claim 1, wherein the upper nipple section includes a plurality of external dimples to permit interlocking engagement with the first tubing end.
- 8. The connector system as recited in claim 1, wherein the lower nipple section includes a plurality of external dimples to permit interlocking engagement with the second tubing end.
- 9. The connector system as recited in claim 7, wherein the lower nipple section includes a plurality of external dimples to permit interlocking engagement with the second tubing end.
- 10. The connector system as recited in claim 1, wherein the plurality of conductors include three conductors to permit the use of three-phase power.
- 11. A coiled tubing connection system, comprising:a first segment of coiled tubing having a first connector end and a first hollow interior; a first power cable disposed in the first hollow interior and having a first plug proximate the first connector end; a second segment of coiled tubing having a second connector end and a second hollow interior; a second power cable disposed in the second hollow interior and having a second plug proximate the second connector end; and a coiled tubing connector having a housing sized to selectively engage the first connector end and the second connector end, the coiled tubing connector further including an internal plug assembly positioned to conductively engage the first plug and the second plug when the first and second connector ends are engaged with the coiled tubing connector.
- 12. The coiled tubing connection system as recited in claim 11, wherein the housing includes a pair of nipple sections sized for insertion into the first connector end and the second connector end.
- 13. The coiled tubing connection system as recited in claim 12, wherein the housing includes an expanded midsection disposed intermediate the first connector end and the second connector end.
- 14. The coiled tubing connection system as recited in claim 13, wherein the coiled tubing connector includes at least one seal disposed about each nipple section.
- 15. The coiled tubing connection system as recited in claim 14, wherein the coiled tubing connector includes an internal seal disposed between the housing and the internal plug assembly.
- 16. The coiled tubing connection system as recited in claim 11, wherein the internal plug assembly includes opposed female plug ends having receptacles arranged to receive the first plug and the second plug.
- 17. The coiled tubing connection system as recited in claim 11, wherein the internal plug assembly includes opposed plug ends in which at least one of the opposed plug ends comprises a female plug end.
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Foreign Referenced Citations (4)
Number |
Date |
Country |
0 612 913 |
Aug 1994 |
EP |
2 167 616 |
Jun 1986 |
GB |
2 327 441 |
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GB |
2 340 155 |
Feb 2000 |
GB |