Technical Field
[0001] The disclosure pertains generally to thermal buffering of electronic components and
more particularly to thermal buffering of downhole electronic components using phase
change materials.
Background
[0002] Components of petroleum well downhole assemblies can be subjected to pressures, temperatures,
and fluid compositions that are hostile to temperature-sensitive components. Temperature-sensitive
components, such as various electronic components in downhole assembly tools can initially
be protected from well temperatures by a housing, but the temperature within the housing
eventually rises above a desired operating temperature as heat-producing components
operate in an enclosed environment.
[0003] Therefore, a need remains for thermal buffering of temperature-sensitive components
particularly in the high temperature environment of a petroleum well.
Summary
[0004] This document provides methods, systems, and techniques relating to thermal buffering
of heat-sensitive components.
[0005] In some embodiments, a downhole assembly of a wellsite system includes a housing
containing an electronic component that can generate heat and a first phase change
material. The first phase change material is packaged in a first container comprising
a first microporous material and placed in thermal communication with the electronic
component such that the heat generated by the electronic component can transfer to
the first phase change material. The first phase change material has a phase change
at a temperature at or below a first temperature.
[0006] In some embodiments, the downhole assembly further includes a second phase change
material packaged in a second container comprising a second microporous material.
The second phase change material is also in thermal communication with the electronic
component such that the heat generated by the electronic component can also transfer
to the second phase change material. The second phase change material has a phase
change at a temperature at or below a second temperature. The phase change temperature
of the second phase change material is different than the phase change temperature
of the first phase change material.
[0007] In some embodiments, the first temperature is a predetermined maximum operating temperature
of the electronic component.
[0008] In some embodiments, the first phase change material changes from solid to liquid,
liquid to gas, or solid to gas at a temperature at or below the first temperature.
[0009] In some embodiments, the second phase change material changes from solid to liquid,
liquid to gas, or solid to gas at a temperature at or below the second temperature.
[0010] In some embodiments, each of the first and second temperatures is at or below a predetermined
maximum operating temperature of the electronic component.
[0011] In some embodiments, the first or second container comprises a microporous polytetrafluoroethylene
material, a microporous film, a laminate, or a coated fabric.
[0012] In some embodiments, the first phase change material is included at a mass sufficient
to increase operating time of the electronic component at or below the first temperature
by at least about 10%.
[0013] In some embodiments, the downhole assembly includes two phase change materials at
a combined mass sufficient to increase operating time of the electronic component
at or below a predetermined maximum operating temperature by at least about 10%.
[0014] In some embodiments, a method includes the steps of: a) providing downhole assembly
comprising a housing, an electronic component disposed inside the housing, and a first
phase change material disposed inside the housing; b) placing the first phase change
material in thermal communication with the electronic component; and c) absorbing
heat generated by the electronic component by a phase change of the first phase change
material at or below a first temperature.
[0015] In some embodiments, the method provides a downhole assembly further comprising a
second phase change material disposed inside the housing. The method further includes
the steps of a) placing the second phase change material in thermal communication
with the electronic component such that heat generated by the electronic component
can transfer to the second phase change material; and b) absorbing the heat generated
by the electronic component by a phase change of the second phase change material
at or below a second temperature.
[0016] In some embodiments, the method further includes automatically stopping operation
of the electronic component when a temperature inside the housing reaches the first
or second temperature.
[0017] In some embodiments, the method further includes stopping operation of the electronic
component at a time point calculated to be at or before a temperature in the housing
reaches the first or second temperature.
[0018] In some embodiments, the first phase change material is provided at a mass sufficient
to increase operating time of the electronic component at or below the first temperature
by at least about 10%.
[0019] In some embodiments, the first phase change material and the second phase change
material are provided at a combined mass sufficient to increase operating time of
the electronic component at or below a predetermined maximum operating temperature
of the electronic component by at least about 10%.
[0020] In some embodiments, the first and second temperatures are at or below a predetermined
maximum operating temperature of the electronic component.
[0021] While multiple embodiments with multiple elements are disclosed, still other embodiments
and elements of the present invention will become apparent to those skilled in the
art from the following detailed description, which shows and describes illustrative
embodiments of the invention. Accordingly, the drawings and detailed description are
to be regarded as illustrative in nature and not restrictive.
Brief Description of the Figures
[0022] Figure 1 is a schematic diagram of a wellsite system in accordance with an embodiment
of the disclosure.
[0023] Figure 2 is a schematic cross-sectional diagram of an assembly in accordance with
an embodiment of the disclosure.
[0024] Figure 3 is an example of a phase change material in a flexible container in accordance
with an embodiment of the disclosure.
[0025] Figure 4 is a flow chart illustrating a method in accordance with an embodiment of
the disclosure.
[0026] Figure 5 is a flow chart illustrating a method in accordance with an embodiment of
the disclosure.
Detailed Description
[0027] One or more specific embodiments of the present disclosure will be described below
including method, apparatus and system embodiments. These described embodiments and
their various elements are only examples of the presently disclosed techniques. It
should be appreciated that in the development of any such actual implementation, as
in any engineering or design project, numerous implementation-specific decisions can
be made to achieve the developers' specific goals, such as compliance with system-related
and business-related constraints, which can vary from one implementation to another.
Moreover, it should be appreciated that such a development effort might be time consuming,
but would nevertheless be a routine undertaking of design, fabrication, and manufacture
for those of ordinary skill having the benefit(s) of this disclosure.
[0028] When introducing elements of various embodiments of the present disclosure, the articles
"a," "an," and "the" are intended to mean that there are one or more of the elements.
The terms "comprising," "including," and "having" are intended to be inclusive and
mean that there can be additional elements other than the listed elements. Additionally,
it should be understood that references to "one embodiment" or "an embodiment" of
the present disclosure are not intended to be interpreted as excluding the existence
of additional embodiments that also incorporate the listed elements.
[0029] Figure 1 illustrates an embodiment of a wellsite apparatus, system, and methodology.
The wellsite system of Figure 1 can be onshore or offshore for, for example, exploring
and producing oil, natural gas, and other resources that can be used, refined, and
otherwise processed for fuel, raw materials and other purposes. In the wellsite system
of Figure 1, a borehole 11 can be formed in subsurface formations, such as rock formations,
by rotary drilling using any suitable technique. A drillstring 12 can be suspended
within the borehole 11 and can have a bottom hole assembly 100 that includes a drill
bit 105 at its lower end. A surface system of the wellsite system of Figure 1 can
include a platform and derrick assembly 10 positioned over the borehole 11, the platform
and derrick assembly 10 including a rotary table 16, kelly 17, hook 18, and rotary
swivel 19. The drillstring 12 can be rotated by the rotary table 16, energized by
any suitable means, which engages the kelly 17 at the upper end of the drillstring
12. The drillstring 12 can be suspended from the hook 18, attached to a traveling
block (not shown), through the kelly 17 and the rotary swivel 19, which permits rotation
of the drillstring 12 relative to the hook 18. A topdrive system could alternatively
be used, which can be a topdrive system well known to those of ordinary skill in the
art.
[0030] In the wellsite system of Figure 1, the surface system can also include drilling
fluid or mud 26 stored in a pit 27 formed at the wellsite. A pump 29 can deliver the
drilling fluid 26 to the interior of the drillstring 12 via a port in the swivel 19,
causing the drilling fluid to flow downwardly through the drillstring 12 as indicated
by the directional arrow 8. The drilling fluid 26 can exit the drillstring 12 via
ports in the drill bit 105, and circulate upwardly through the annulus region between
the outside of the drillstring 12 and the wall of the borehole 11, as indicated by
the directional arrows 9. In this manner, the drilling fluid 26 lubricates the drill
bit 105 and carries formation cuttings up to the surface, as the fluid 26 is returned
to the pit 27 for recirculation.
[0031] The bottom hole assembly 100 of the wellsite system of Figure 1 can, as one example,
include one or more of a logging-while-drilling (LWD) module 120, a measuring-while-drilling
(MWD) module 130, a roto-steerable system and motor 150, and the drill bit 105. As
will be appreciated, bottom hole assembly equipment can include heat-producing components
(e.g., electronic components) as well as heat-sensitive components (e.g., electronic
components), where thermal buffering may be beneficial.
[0032] As shown in Figure 1, the wellsite system is used for a logging-while-drilling (LWD)
or measurement-while-drilling (MWD) operation performed on a land based rig, but could
be any type of oil/gas operations (e.g., wireline, coiled tubing, testing, completions,
production, etc.) performed on a land based rig or offshore platform.
[0033] Figure 2 is a schematic cross-sectional illustration of a downhole assembly 200 that
can, for example, be included in an MWD module, an LWD module, or other downhole equipment
such as well formation pressure testing equipment. The assembly 200 includes a housing
210 containing a heat-producing component 220 in thermal communication with a thermal
buffering (e.g. phase change material) component 230. As used herein, a first component
(e.g., a heat-producing component) is considered to be in thermal communication with
a second component (e.g., a phase change material component) if thermal energy from
the first component can be transferred to the second component within housing 210.
In some embodiments, the heat-producing component 220 and the phase change material
component 230 can be in thermal communication by direct physical contact. In some
embodiments, the heat-producing component 220 and the phase change material component
230 can be in thermal communication indirectly such as, for example, through contact
with another component or part of the housing or open space in the container 210.
[0034] A heat-producing component 220 can be an electronic component such as a multichip
module. In some embodiments, a heat-producing component 220 can include individual
electronic parts such as integrated circuit (IC) chips that are soldered or otherwise
secured to a substrate such as a silicone-on-insulator (SOI) or printed circuit board.
In some embodiments, copper wiring traces within the printed circuit board may assist
in carrying thermal energy away from IC chips and other elements within the heat-producing
component 220.
[0035] A phase change material component 230 includes a phase change material packaged in
a container 232 (Figure 3) having any suitable shape. In some embodiments, a phase
change material is packaged in a flexible container. In some embodiments, a phase
change material can be packaged in a container comprising a material that prevents
the phase change material from flowing out of the container 232 when the phase change
material is in a fluid or semi-fluid phase. Materials suitable for use in a phase
change material container include, without limitation, microporous films or membranes
(
e.g., open pore and/or filled pore microporous polytetrafluoroethylene (PTFE), polypropylene,
polyethylene, polyester, nylon, etc.), woven or nonwoven fabrics (
e.g., polyester, polypropylene, and polyethylene spunbonded, spunlaced, meltblown microfiber
fabrics, etc.), laminates, coated fabrics, and the like. Various microporous films
are available from a number of sources including W. L. Gore & Associates. Various
microporous fabrics are available from various sources including Mogul Tekstil, BP
Amoco, and DuPont.
[0036] In some embodiments, a material used to package a phase change material can be chosen
based on the ability to maintain integrity at high temperature and/or the ability
to conduct thermal energy to the packaged phase change material. In some embodiments,
a material used to package a phase change material can be chosen based on a property
(
e.g., hydrophobicity, hydrophilicity, fluidity of one or more phases, etc.) of the chosen
phase change material. In some embodiments, different materials can be used to package
different phase change materials.
[0037] In some embodiments, for example as illustrated in Figure 3, container 232 is flexible,
allowing the phase change material component 230 to be inserted various spaces within
the housing 210. In such embodiments, the phase change material contained within container
232 may be in a form that can be deformed, such as a pliable solid, a fluid, a powder,
a slurry, or a plurality of encapsulated or unencapsulated portions. In some embodiments,
the phase change material can be preformed to fit within a particular space within
container 232.
[0038] A phase change material can be any suitable material that absorbs thermal energy
during a phase change (
e.g., solid to solid, solid to liquid, liquid to gas, or solid to gas) that occurs as
temperature increases. Examples of suitable phase change materials include, without
limitation, paraffins, fatty acids, salt hydrates, and eutectic materials. Various
phase change materials are available from a number of sources including PCM Products
Ltd., PCM Thermal Solutions, Microtek Laboratories, Inc., and Amec Thermasol.
[0039] A phase change material may be chosen for the ability to absorb thermal energy during
a phase change at or below a selected temperature. In some embodiments, a selected
temperature can be at or below a predetermined maximum operating temperature, at or
below which a heat-sensitive component typically does not fail due to thermal stress.
In some embodiments, a selected temperature can be at or below a temperature at which
a heat-sensitive component begins to fail due to thermal stress.
[0040] In some embodiments, assembly 200 includes a plurality of phase change material components
230 separately comprising different phase change materials each with different temperatures
at which a phase change occurs. For example, different phase change materials may
be chosen in order to increase total thermal energy absorption potential over the
use of a single phase change material within the volume available in housing 210.
In some embodiments, additional phase change materials may be chosen for a phase change
that is at or below that of another phase change material. As such, a temperature
can be selected that is at or below a temperature at which a phase change material
changes phases.
[0041] A phase change material can be included in assembly 200 at a mass sufficient to increase
the time at which a heat-producing component 220 can operate at or below a selected
temperature. In some embodiments, a plurality of different phase change materials
can be included in assembly 200 at a combined mass sufficient to increase the time
at which a heat-producing component 220 can operate at or below a predetermined maximum
operating temperature of a heat-sensitive component. In some embodiments, a phase
change material can be included in assembly 200 at a mass sufficient to increase the
time for which a heat-producing component 220 can operate at or below a selected temperature
by at least about 5%. For example, the time for which a heat-producing component 220
can operate at or below a selected temperature can be increased by at least about
7%, 10%, 12%, 15%, 18%, 20%, 25%, 30%, 50%, or more.
[0042] In some embodiments, assembly 200 can further include additional components, such
as a temperature sensor to gauge the temperature within housing 210. In some embodiments,
a thermal switch can be included in assembly 200 that automatically shuts down the
operation of a heat-producing component 220 when the temperature in container 210
reaches a selected temperature. In some embodiments, temperature within housing 210
can be monitored and the operation of a heat-producing component 220 can be switched
off when the temperature in container 210 is observed to reach a selected temperature.
[0043] In some embodiments, the amount of time a heat-producing component 220 can operate
at or below a selected temperature can be calculated based on a latent heat storage
potential and mass of a selected phase change material included in assembly 200. In
some embodiments, operation of a heat-producing component 220 can be stopped at a
time point that is calculated to be at or before reaching a selected temperature.
[0044] As shown in Figure 4, one embodiment of method 1000 includes the steps of providing
a downhole assembly comprising a housing, an electronic component disposed inside
the housing, and a first phase change material also disposed inside the housing 1050;
placing the first phase change material in thermal communication with the electronic
component 1052; and absorbing heat generated by electronic component by a phase change
of the first phase change material at or below a first temperature 1054. In some embodiments,
as shown in Figure 5, a method 1200 can include the steps of providing a downhole
assembly comprising a housing, an electronic component disposed inside the housing,
and a first phase change material and a second phase change material also disposed
inside the housing 1250; placing the first phase change material in thermal communication
with the electronic component 1252; placing the second phase change material in thermal
communication with the electronic component or the first phase change material 1254;
and absorbing heat generated by electronic component by a phase change of the second
phase change material at or below a second temperature 1256.
[0045] In some embodiments, a method 1000 or 1200 can include automatically stopping operation
of the electronic component when a temperature inside the housing reaches the first
or second temperature, or stopping operation of the electronic component at a time
point calculated to be at or before a temperature in the housing reaches the first
or second temperature.
[0046] Various modifications, additions and combinations can be made to the exemplary embodiments
and their various features discussed without departing from the scope of the present
invention. For example, while the embodiments described above refer to particular
features, the scope of this invention also includes embodiments having different combinations
of features and embodiments that do not include all of the above described features.
1. A downhole assembly comprising:
a housing;
an electronic component disposed within the housing, wherein the electronic component
can generate heat; and
a first phase change material packaged in a first container comprising a first microporous
material and disposed within the housing in thermal communication with the electronic
component such that the heat generated by the electronic component can transfer to
the first phase change material, the first phase change material having a phase change
at a temperature at or below a first temperature.
2. The downhole assembly of claim 1, further comprising a second phase change material
packaged in a second container comprising a second microporous material and disposed
within the housing in thermal communication with the electronic component such that
the heat generated by the electronic component can transfer to the second phase change
material, the second phase change material having an phase change at a temperature
that is at or below a second temperature and different than the phase change temperature
of the first phase change material.
3. The downhole assembly of claim 1 or 2, wherein the first phase change material changes
from solid to liquid, liquid to gas, or solid to gas at a temperature at or below
the first temperature.
4. The downhole assembly of claim 2 or 3, wherein the second phase change material changes
from solid to liquid, liquid to gas, or solid to gas at a temperature at or below
the second temperature.
5. The downhole assembly of any of claims 1-4, wherein each of the first and second temperatures
is at or below a predetermined maximum operating temperature of the electronic component.
6. The downhole assembly of any of claims 1-5, wherein the first or second microporous
material comprises a microporous polytetrafluoroethylene material, a microporous film
or membrane, a laminate, or a coated fabric.
7. The downhole assembly of any of claims 1-6, wherein the first phase change material
is included at a mass sufficient to increase operating time of the electronic component
at or below the first temperature by at least about 10%.
8. The downhole assembly of any of claims 2-7, wherein the first phase change material
and the second phase change material are included at a combined mass sufficient to
increase operating time of the electronic component at or below a predetermined maximum
operating temperature of the electronic component by at least about 10%.
9. A method comprising:
providing a downhole assembly comprising a housing; an electronic component disposed
inside the housing; and a first phase change material disposed inside the housing;
placing the first phase change material in thermal communication with the electronic
component; and
absorbing heat generated by the electronic component by a phase change of the first
phase change material at or below a first temperature.
10. The method of claim 9, wherein the downhole assembly further comprises a second phase
change material disposed inside the housing; the method further comprising:
placing the second phase change material in thermal communication with the electronic
component or the first phase change material; and
absorbing the heat generated by the electronic component by a phase change of the
second phase change material at or below a second temperature.
11. The method of claim 9 or 10, further comprising automatically stopping operation of
the electronic component when a temperature inside the housing reaches the first or
second temperature.
12. The method of claim 9 or 10, further comprising stopping operation of the electronic
component at a time point calculated to be at or before a temperature in the housing
reaches the first or second temperature.
13. The method of any of claims 9-12, wherein the first phase change material is provided
at a mass sufficient to increase operating time of the electronic component at or
below the first temperature by at least about 10%.
14. The method of any of claims 10-13, wherein the first phase change material and the
second phase change material are provided at a combined mass sufficient to increase
operating time of the electronic component at or below a predetermined maximum operating
temperature of the electronic component by at least about 10%.
15. The method of any of claims 9-14, wherein each of the first and second temperatures
is at or below a predetermined maximum operating temperature of the electronic component.