Patent Application
20190055817
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.
Downhole tools, such as logging tools, steering and measurement tools, drilling tools, among others, are typically sent into boreholes formed deep within the earth. These tools may often be subject to the high temperatures of the downhole environment. Most downhole tools include an electronics portion. These downhole electronics are usually packaged in an atmospheric environment inside a pressure housing. In some cases, the temperature in the borehole can exceed the operating limit of some electronics components. In such cases, components with high temperature ratings may be selected by design, or various mechanisms are used to keep the electronics temperature below the operating limit. Such mechanism may include but are not limited to thermal flasks, thermoelectric coolers, heat pipes, etc.
Additionally, aside from high bolehole temperatures, many of these electronic components are power-consuming electronics which may generate a large amount of heat on their own. This can also cause component temperature to rise beyond the operating limit if the generated heat is not managed properly. For example, even the most power efficient metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated-gate bipolar transistors (IGBTs) can generate significant amount of heat during operation. Thus, heat management is an ongoing object of downhole tool design.
For a detailed description of the embodiments of the invention, reference will now be made to the accompanying drawings in which:
The present disclosure provides methods and systems for increasing heat dissipation from electronics inside of downhole tools by providing a thermal pathway between heat generating electronics and the outer housing of the downhole tool, thereby dissipating heat into the environment. The present disclosure provides a heat sink which contacts both the heat generating electronics as well as the tool housing to establish such a thermal pathway. The heat sink may also have a tapered shape to provide ease of installation as well as good contact.
Turning now to the figures,
The well 114 may be a vertical well, such as that illustrated in
The drilling system 116 may include a drill string 103 suspended downhole from the well site 106. The drill string 103 includes a drill pipe 112 and a bottom hole assembly (BHA) 120. The drill pipe 112 may include a plurality of segments, each of which are added to the drill pipe 112 as the well 114 is drilled and increasing length of drill pipe 112 is required. The drill pipe 112 provides the length required for the BHA 120 to reach well bottom and drill further into the formation. The drill pipe 112 may also deliver drilling fluid from surface facilities at the well site 106 to the BHA 120.
The BHA 120 may include one or more of a wide variety of downhole tools 122 and components configured to carry out the functions of the well operation 100, such as to form the wellbore 114. Such tools 122 may include, but are not limited to, logging while drilling (LWD) or measurement while drilling (MWD) tools, rotary steering tools, directional drilling tools, motors, reamers, hole enlargers or stabilizers, among others. Many of these downhole tools 122 include electronic components which generate heat inside of the tool 122. The number and types of tools 122 included in the BHA 120 may depend on anticipated downhole drilling conditions and the type of wellbore that is to be formed.
Accordingly, other types of well operations 100 will include other types of downhole tools 122 for carrying out the functions of the respective well operation 100. In some embodiments, the BHA 120 includes a power generation unit 123 which may also be considered a type of downhole tool 122. The power generation unit 123 may be a mud-based power generator that includes a turbine that rotates when traversed by drilling fluid, thereby generating power. The drill string 103 also includes a drill bit 101 for cutting through the formation. In most wells 114, there is a space between the downhole tools 122 and the walls of the well 114 called an annulus 108. In some embodiments, such as in a drilling operation, drilling fluid may flow through the annulus 108. In a production operation, production fluid may flow through the annulus 108.
As noted, the example well operation illustrated in
The electronics assembly 202 is coupled to the chassis within the tool housing 204 and between the chassis and the tool housing 204. The electronics assembly 202 includes a heat sink 214 and a circuit board assembly 216, such as a printed circuit board assembly (PCBA). The circuit board assembly 216 is mounted onto the heat sink 214. In some embodiments, the circuit board assembly 216 includes a plurality of various electronic components such as processors, transistor devices, circuit elements, among many other possible components. The electronic components may include one or more heat generating components 222.
The heat sink 214 includes an inner surface 218 and an outer surface 220. The electronics board is mounted to the heat sink 214 such that the one or more heat generating components 222 are in contact with the inner surface 218 of the heat sink 214. Specifically, the heat generating components 222 may include a heat dissipating surface which is put in contact with the inner surface 218 of the heat sink 214. In some embodiments, when the electronics assembly 202 is fully installed in the downhole tool 122, the outer surface 220 of the heat sink 214 is in contact with the inner surface 208 of the tool housing 204. The heat sink 214 may be fabricated from thermally conductive materials such as plastic, aluminum, copper, among others, which enable heat transfer between the inner surface 218 and the outer surface 220. This allows heat dissipated from the heat generating components 222 to be transferred to the heat sink 214 and then to the tool housing 204 via the heat sink 214. The heat can then be dissipated out of the tool housing 204 and into the annulus 106, thus reducing the temperature rise of heat producing components 222 and other components on the circuit board assembly 216. The arrows indicate a thermally conductive path for dissipation of heat from the components 222 to the housing 204 through the heat sink 214.
The electronics assembly 202 may be coupled to a spring 224 which biases against a spring block 226. In some embodiments, as temperature increases or decreases over the course of an operation, the materials of the heat sink 214 and/or tool housing 204 may expand or contract, which causes the electronics assembly 202 to change positions along the chassis 212. The spring 224, which is fixed at one end to the chassis 212 via the spring block 226, keeps the heat sink 214 urged against the tool housing 204. In some embodiments, the outer surface 220 of the heat sink 214 has a tapered portion and the inner surface 208 of the tool housing 204 has a complementary tapered portion such that close and smooth contact is maintained between the heat sink 214 and the tool housing as the electronics assembly is urged by the spring 224. The tapered shape may also provide ease of installation as the electronics assembly 202 is inserted into the tool housing 204.
When the thermal actuators 804 are not actuated, the heat sink 214 is retracted close to the chassis 212 and away from the tool housing 204, as illustrated in
The thermal actuators 804 illustrated and described herein are only one example of a thermal expansion device that can be used to hold the heat sink 214 away from the tool housing 204 when the temperature is below a threshold and urge the heat sink 214 into contact with the tool housing 204 when the temperature is above the threshold temperature. Other examples may include a thermal expansion material, pistons, memory metals, among others.
In addition to the embodiments described above, many examples of specific combinations are within the scope of the disclosure, some of which are detailed below:
A downhole tool system, comprising:
The system of example 1, wherein the electronic components are coupled to the chassis via a coupling mechanism configured to provide a degree of relative movement between the electronic components and the chassis.
The system of example 2, wherein the coupling mechanism comprises a peg or screw disposed through a slot.
The system of example 1, wherein the heat sink comprises a thermally conductive material, and wherein the inner surface of the heat sink is configured to be thermally communicative with the outer surface of the heat sink.
The system of example 1, herein the tool housing comprises an inner tapered portion having a shape complementary to the tapered portion of the heat sink.
The system of example 1, wherein the at least a portion of the electronic components are coupled to a circuit board, the portion of electronic components comprising heat emitting surfaces, and wherein the heat emitting surfaces are in contact with the inner surface of the heat sink.
The system of example 1, further comprising a spring member configured to bias the heat sink against the tool housing.
A downhole tool system, comprising:
The system of example 8, wherein the at least a portion of the electronic components are coupled to a circuit board, the portion of electronic components comprising heat emitting surfaces, and wherein the heat emitting surfaces are in contact with the inner surface of the heat sink.
The system of example 8, wherein the heat sink comprises a thermally conductive material, and wherein the inner surface of the heat sink is configured to be thermally communicative with the outer surface of the heat sink.
The system of example 8, wherein the electronic components are mounted onto opposite sides of the chassis.
The system of example 8, wherein the thermal expansion device comprises a thermal actuator.
The system of example 8, wherein the electronic components are a part of an electronics assembly which further comprises a retraction mechanism configured to move the heat sink and circuit assembly inward and away from the tool housing.
The system of example 8, wherein the thermal expansion device comprises a thermally expansive material configured to expand in volume upon reaching the temperature threshold.
An electronics assembly for thermal management in downhole tools, comprising:
The electronics assembly of example 15, wherein the thermal expansion device is a thermal actuator.
The electronics assembly of example 15, wherein the thermal expansion device comprises a thermally expansive material configured to expand in volume upon reaching the temperature threshold.
The electronics assembly of example 15, wherein the circuit assembly comprises an electronic component coupled to a circuit board, the electronic component comprising a heat emitting surface, and wherein the heat emitting surface is in contact with the inner surface of the heat sink.
The electronics assembly of example 15, wherein the heat sink comprises a thermally conductive material, and wherein the inner surface of the heat sink is thermally communicative with the outer surface of the heat sink.
The electronics assembly of example 15, wherein the electronics assembly further comprises a retraction mechanism configured to retract the heat sink and circuit assembly.
This discussion is directed to various embodiments of the invention. The drawing figures are not necessarily to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.
Certain terms are used throughout the description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function, unless specifically stated. In the discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. In addition, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. The use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components.
Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2015/061578 | 11/19/2015 | WO | 00 |
