1. Field of the Invention
The invention relates generally to the design and construction of electrical connections for use in sondes and other wellbore logging tools. In particular aspects, the invention provides devices and methods for improved packaging of electrically conductive elements within such a tool and for protecting said elements against wellbore fluids.
2. Description of the Related Art
A number of tools are known today for logging or sensing conditions within a wellbore during various portions of the well productions process. These sensing tools, or sondes, include an outer casing or sub that is often disposed into a wellbore on wireline. Alternatively, the sub may be disposed into the wellbore on coiled tubing or as part of the drill string or even production tubing. The sensing tools are capable of detecting a wide variety of downhole conditions, including temperature, pressure, porosity, resistivity, and so forth. The sensing tool generally features a sensor disposed on the outer side surface of the sub or embedded therewithin the side surface. Electronic equipment is disposed within the interior of the sub, and is typically contained within compartments behind sealed bulkheads that are located proximate each axial end of the sub. This electronic equipment typically includes processing circuitry, storage media, and power sources.
Fluid sealing is provided around the sensor to prevent entry of fluid into the interior of the sub. If damaged, however, the seal may permit fluid to flow into the interior of the sub. A typical external environment for a sonde would be one where the wellbore fluid is at a pressure state that higher than the interior of the sub. The pressure difference may range from 50 psi to 30,000 psi. Once inside the sub, the fluid may corrode or otherwise destroy the conductivity of the wiring that extends between the sensor and the components housed within the two axially-located chambers. Additionally, if either of the bulkheads are breached, the intruding fluid might easily destroy the electronic components housed within. Additionally, present techniques for constructing sondes with bulkheads and the necessary bulkhead electrical connectors are time consuming and costly.
The present invention addresses the problems of the prior art.
In aspects, the invention provides devices and methods for construction of a downhole tool such as a sonde or other sensing tool that includes a side-entry leak protector connector arrangement. The side-entry leak protector connector provides for improved fluid sealing against fluid that might enter a tool proximate the side-mounted device such as a sensor component. An exemplary side entry leak protector connector assembly is described having a body that is secured within a passage within the sub between a shoulder and a retaining member such as a snap ring. The body can be formed of polyethyl-ether-keytone, a metal, a composite or other suitable material. The side entry leak protector connector assembly includes glass-sealed conductive elements and pin connectors to operably engage mating electrical connections leading to an external device such as sensors, the components housed within the sub or elsewhere in the downhole tool.
In other aspects, the present invention provides features that reduce the risk of wellbore fluid invading the interior of the downhole tool. For instance, the connector body can be surrounded by one or more seals that prevent fluid invasion from a lateral opening in a downhole tool. In one embodiment, the seal or seals are configured to withstand a pressure difference between an atmospheric pressure in the downhole tool and an external wellbore pressure. Additionally, the body of the protector connector can include an annular fluid chamber that acts as a reservoir to contain or capture fluid that might enter the sub. Leak protection can also be provided by applying a pressure compensating material around the body. It should be appreciated that embodiments of the present invention eliminate the need for interior bulkheads within the sub.
Embodiments of the present invention also provide enhanced functionality for the downhole tool. For example, the connector can include a body having an axial bore that extends partially or fully through the body. One or more conductors run axially along and adjacent to the axial bore. Advantageously, the axial bore can be configured to perform any number of functions such as acting as a conduit that receives data conducting elements or as a hydraulic conduit for receiving fluid. Another suitable bore configuration includes a cavity that houses downhole devices such as circuitry, batteries, or processors. Yet another suitable bore configuration is an access conduit through which one or more manipulable members such as wires, cables, and linkages can extend.
It should be understood that examples of the more important features of the invention have been summarized rather broadly in order that detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto.
For detailed understanding of the present invention, references should be made to the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:
The present invention relates to devices and methods for providing connection and sealing arrangements for downhole tools. The present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein.
Electronic equipment 34 is contained in each of the chambers 20, 22. The electronic equipment 34 may include processing circuitry, power sources, storage media or the like. Additionally, a sensor 36 for detecting a downhole condition is mounted on the exterior of the housing 18 and provides an electrical pin connector 38 that is disposed within the lateral opening 32. It should be understood that the sensor 36 is merely representative of any device positioned on or external to the downhole tool 14.
A side entry leak protector connector assembly is shown generally at 40 in
The protector connector assembly 40 resides within the axial passage 28 so that one axial end 44 of the protector connector assembly 40 abuts the shoulder 30 of the passage 28. A snap ring 58 retains the protector connector assembly 40 within the passage 28.
In operation, the side entry leak protector connector assembly 40 provides superior prevention of and protection against fluid that might enter the housing 18 via the lateral opening 32. The circumferential channel 48 contains any fluid that might enter the lateral opening 32. In addition, the 0-ring seals 50 provide a secondary seal against fluid ingress past the protector 40 and into the chambers 20, 22. This eliminates or reduces the need for bulkheads to be constructed within the housing 18 to seal off the chambers 20, 22 from the axial passage 28. Additionally, the glass-sealing of the conductive elements 52a, 52b within the body 42 prevents damage to the conductive elements 52a, 52b from borehole fluids.
Referring now to
In one embodiment, the connector 70 has a body 72 that includes one or circumferentially arrayed conductors 74 and one or more axial bores 76. In one arrangement, the conductors 74 and the axial bore 76 run substantially parallel along the body 72. It should be appreciated that this parallel arrangement provides the connector 70 with a plurality of transmission paths or conduits, each of which can be adapted to perform the same function or different functions. For example, the conductors 74, which can include metal wires or optical fibers and suitable terminals, can transmit power, data signals, and/or command signals. The axial bore 76 can also include conductors adapted to convey power, data signals or command signals. However, the axial bore 76 can also be utilized as a hydraulic conduit that transfers pressure pulses or allows fluid flow across the body 72. In still other variant, the axial bore 76 can be formed as an access way for receiving beams, linkages, cables, wires or other members that can be manipulated. In still another variant, the axial bore 76 can be formed to house or otherwise accommodate devices such as electrical components, circuitry, batteries or other equipment.
As noted above, the connector 70 is in part configured to contain or arrest fluid leaks through the opening 32. Such fluid leaks can occur if the seal elements 37, if present, fail or for some other reason wellbore fluid flows through the opening 32. In one embodiment, the body 72 includes one or more seal elements 78 that form a fluid barrier between the body 72 and the downhole tool 14′. For example, one or more seal elements 78 can be positioned uphole and downhole of the opening 32. In an exemplary arrangement, the seal elements 78 are configured to maintain a fluid barrier in an environment wherein the exterior pressure is wellbore pressure and the pressure inside the tool 14′ is approximately atmospheric. Thus, the seal elements 78 can form a primary or a secondary barrier against fluid invasion into the interior of the tool 14′
In one arrangement, the body 72 has one or more windows or access openings 80 through which wiring running from the exterior device 36 can connect with the conductors 74. The access opening 80 exposes the conductor 74 to allow a splice into the conductor or to access to a take-out or other suitable terminal for forming a connection to the conductor 74. Additionally, an annular groove or recess 82 can optionally be formed on an outer surface 84 of the body 72. In a manner previously described, the recess 82 can function as a reservoir that retains fluid entering through the lateral opening 32 and prevents or at least limits such fluid from entering the interior of the tool 14′. Also, optionally, a pressure compensating material can be applied around the body 72 for further protection against fluid leaks. For example, a pressure compensating material can be applied the access openings 80 and/or the recess 82 to further function to prevent fluid leaking into the tool 14′.
It should be understood that the several features and aspects discussed in connection with
In practice, the arrangements of the present invention provide for superior leak protection as well as ease of establishing electrical connectivity between sensors and electrical components 34 that are housed within the sonde housing or in neighboring housings.
Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.
This application is a continuation-in-part of U.S. patent application Ser. No. 10/635,250, filed on Aug. 6, 2003, titled “Side Entry Leak Protection for Sondes.”
Number | Date | Country | |
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Parent | 10635250 | Aug 2003 | US |
Child | 11417418 | May 2006 | US |