Patent Application
20140242825
In a variety of well applications, electrical power is delivered to downhole components. For example, electric submersible pumping system applications use submersible electric motors that are powered via a power cable run downhole along a tubing string. The power cable is connected to the submersible electric motor by a connector, sometimes referred to as a pothead.
Because of the high pressure, high temperature, harsh wellbore environment, the connector is designed to protect both the power cable and the powered component from the environmental factors. A variety of elastomeric elements are employed to help form seals between the pothead and both the submersible motor and the power cable. The submersible motor is generally a three-phase motor, and the pothead is designed as a single connector having a triad configuration of three conductors for carrying three-phase power. Difficulties can arise in adequately sealing the pothead against the deleterious effects of the harsh downhole environment over substantial periods of submersible motor operation.
In general, the present invention provides a system and method for connecting a power cable to a submersible component. A connector system comprises a plurality of individual connectors for connecting power carrying conductors to the submersible component. Each of the individual connectors is separately connectable to the submersible component which enables improved sealing with respect to the submersible component. When multi-phase power is provided to the submersible component, an individual connector can be used for each phase.
This summary section is not intended to give a full description of the subject matter. A detailed description with example embodiments follows.
Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:
In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
The present invention generally relates to a system and method for connecting a multi-conductor power cable to a submersible component in a high temperature environment. For example, the connection system can be used in a harsh, high temperature, high pressure well environment for connecting a power cable to a submersible motor. The connection system uses a plurality of individual connectors coupled to the power cable and separately connectable to the submersible component. The individual, separate connectors avoid the traditional requirement of a single connector pothead for electrically coupling a plurality of conductors to a submersible component.
In many applications, the connection system enables two or more individual connections to be made with corresponding submersible component contacts. For example, if three-phase power is provided to a submersible electric motor, individual connectors can be used for each phase. In one embodiment, the connector for each electrical input phase uses an outer metallic tubing which seals to a motor housing via a metal-to-metal connection that requires no elastomer sealing elements. By way of example, each metal-to-metal sealed connection can be formed and maintained with a compression fitting.
Referring generally to
The well system 20 may comprise a variety of well systems used to perform many types of well related operations. In general, the well system 20 comprises at least one submersible, electrically powered component 36 that receives power via an electric power cable 38. Power cable 38 is mechanically and electrically connected to submersible component 36 by a connector system 40. Connector system 40 is sealed with respect to submersible component 36 and power cable 38 to protect both component 36 and cable 38 from the high pressure, high temperature, harsh wellbore environment 42. The harsh wellbore environment 42 is typically at a temperature of greater than 300 degrees Fahrenheit and under substantial pressure. Additionally, a variety of harsh gases, liquids and other substances found in wellbore environment 42 can have deleterious effects on submersible component 36 and/or power cable 38 if the seal is not maintained.
In the embodiment illustrated in
Connector system 40 is designed to improve the dependability of the connection between power cable 38 and submersible powered component 36. In
In the embodiment illustrated, each individual connector 60 is separately connected and disconnected with a corresponding connector region 62 of submersible component 36, e.g., a submersible electric motor. Each connection with submersible component 36 may be formed as a sealed metal-to-metal connection to limit or avoid the use of conventional elastomer seal elements. In one example, each connector 60 comprises a sleeve 64 that may be formed of a metallic material. Each sleeve 64 surrounds a corresponding conductor 58 and is separated from the corresponding conductor 58 by an insulation layer 66. Each sleeve 64 may be used to facilitate the metal-to-metal seal with the submersible component 36 and to further facilitate a seal with power cable 38.
Individual sealed connections can be formed with various components having a number of configurations. In the embodiment illustrated, however, each connector 60 is in the form of a compression fitting having a male compression thread fitting 68 that is attached to submersible component 36 by a threaded engagement, a weldment, or another suitable attachment mechanism. Each illustrated connector 60 further comprises a female compression thread fitting 70 that couples the corresponding sleeve 64 to the male compression thread fitting 68. Male compression thread fitting 68 and female compression thread fitting 70 are threaded together and sufficiently torqued to provide the pressure seal needed to prevent wellbore fluids from entering submersible component 36.
Each of the sleeves 64 can be formed from various materials that allow the male and female compression thread fittings 68, 70 to grip onto the sleeve 64 and provide the necessary seal. Additionally, each individual sleeve 64 may be sealed to the underlying insulation layer 66 used on the corresponding conductor 58 to further provide a barrier against wellbore fluids entering submersible component 36.
With respect to power cable 38, each sleeve 64 is used to form a seal with the connection end of the power cable. For example, each sleeve 64 can be sealed with respect to a jacket 72, e.g., a lead jacket, of the power cable 38 and/or with the conductor insulation layer 66 surrounding each conductor 58. The sealed connection can be accomplished according to several techniques, including soldering or welding between each sleeve 64 and the power cable jacket 72. Alternatively, each sleeve 64 can be taped with respect to the jacket 72 and/or insulation layer 66. In other embodiments, adhesives can be used to bind each sleeve 64 to the jacket 72 and/or conductor insulation 66. The seals formed between connector system 40 and submersible component 36/power cable 38 are capable of continuous operation in a well environment at temperatures greater than 300 degrees Fahrenheit.
The connector system 40 also can be used to facilitate formation of electrical connections between the power cable 38 and the submersible component 36. For example, an electrical connection can be made for each phase by connecting individual conductors 58 with submersible component 36 via plug-in style connections or tape-in style connections.
Referring generally to
As illustrated, each conductor 58 terminates with a terminal 76 designed for engagement with a corresponding contact 78 of submersible component 36. Each terminal 76 is surrounded by a shroud 80 which may be formed from an insulation grade molded or machined material. Additionally, a seal member 82, such as an elastomeric seal, can be disposed within individual connector housing 74. During connection of the individual connector 60 to submersible component 36, the seal member 82 is energized to seal between, for example, conductor insulation 66 and connector housing 74.
In another embodiment, the electrical connection is formed via a tape-in style connection, as illustrated in
Referring generally to
The pothead design, in which individual connectors 60 are used to connect a plurality of individual conductors/phases to a powered submersible component, promotes improved reliability and durability of the connection. Furthermore, formation of a metal-to-metal connection between a portion of each individual connector and a submersible component housing further promotes the longevity of the connector by eliminating materials susceptible to the detrimental effects of the harsh wellbore environment. It should be noted, however, that a variety of connector components can be used to form the mechanical connection between the individual connectors and the powered submersible component. Similarly, a variety of structural components and techniques can be used to mechanically seal each connector to the power cable. Additionally, various components and techniques can be used to form the electrical connection between each conductor/phase of the power cable and the corresponding contact of the submersible component via the individual connector.
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the subject matter. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
This continuation patent application claims the benefit of priority to U.S. patent application Ser. No. 12/141,468 to Watson et al., filed on Jun. 18, 2008 and incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12141468 | Jun 2008 | US |
| Child | 14142994 | US |
