U.S. patent application number 10/973133 was filed with the patent office on 2006-04-27 for downhole cooling system.
This patent application is currently assigned to Halliburton Energy Services, Inc.. Invention is credited to Christopher A. Golla, James E. Masino, Roger L. Schultz.
Application Number | 20060086506 10/973133 |
Document ID | / |
Family ID | 36205144 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060086506 |
Kind Code |
A1 |
Golla; Christopher A. ; et
al. |
April 27, 2006 |
Downhole cooling system
Abstract
Apparatus and methods for operating an electronics assembly of a
downhole tool. A method comprises disposing a temperature-sensitive
electronic component within an insulated chamber contained within a
downhole tool. The temperature of the temperature-sensitive
electronic component is monitored and a temperature control system
is selectively activated to regulate the temperature of the
temperature-sensitive electronic component. A downhole electronic
assembly comprises a temperature-sensitive electronic component and
a temperature-tolerant electronic component in electrical
communication with the temperature-sensitive electronic component.
An insulating chamber provides a thermal barrier between the
temperature-sensitive electronic component and the
temperature-tolerant electronic component. A temperature control
apparatus in thermal communication with the temperature-sensitive
component.
Inventors: |
Golla; Christopher A.;
(Houston, TX) ; Masino; James E.; (Houston,
TX) ; Schultz; Roger L.; (Aubrey, TX) |
Correspondence
Address: |
CONLEY ROSE, P.C.
PO BOX 3267
HOUSTON
TX
77253-3267
US
|
Assignee: |
Halliburton Energy Services,
Inc.
Houston
TX
|
Family ID: |
36205144 |
Appl. No.: |
10/973133 |
Filed: |
October 26, 2004 |
Current U.S.
Class: |
166/302 ; 166/57;
166/65.1 |
Current CPC
Class: |
E21B 47/017
20200501 |
Class at
Publication: |
166/302 ;
166/057; 166/065.1 |
International
Class: |
E21B 43/24 20060101
E21B043/24 |
Claims
1. A method for operating an electronics assembly of a downhole
tool, the method comprising: disposing a temperature-sensitive
electronic component within an insulated chamber contained within a
downhole tool; monitoring the temperature of the
temperature-sensitive electronic component; and selectively
activating a temperature control system to regulate the temperature
of the temperature-sensitive electronic component.
2. The method of claim 1 wherein the temperature of the
temperature-sensitive electronic component is maintained within a
predetermined range of temperatures.
3. The method of claim 2 wherein the predetermined range of
temperatures has a lower limit higher than the ambient temperature
at the surface.
4. The method of claim 3 wherein the predetermined range of
temperatures has an upper limit lower than the ambient temperature
in the wellbore.
5. The method of claim 1 wherein selectively activating the
temperature control system further comprises: increasing the
temperature of the electronic component when temperature is below
the predetermined range; and decreasing the temperature of the
electronic component when the temperature is above the
predetermined range.
6. The method of claim 1 wherein the temperature control system
comprises a thermoelectric cooler.
7. The method of claim 1 wherein the temperature control system is
only activated when the temperature-sensitive electronic component
is needed to perform selected functions.
8. The method of claim 1 wherein selectively activating the
temperature control system further comprises: not regulating the
temperature of the temperature-sensitive electronic component;
activating the temperature control system to regulate the
temperature of the temperature-sensitive electronic component so
that the component can perform a selected function; and
deactivating the temperature control system.
9. A method for controlling the temperature of a downhole
electronic component, the method comprising: isolating a
temperature-sensitive electronic device within an insulated chamber
disposed within a downhole tool; and regulating the temperature
within the insulated chamber by intermittently activating a
temperature control system.
10. The method of claim 9 wherein the temperature within the
isolated chamber is maintained within a predetermined range of
temperatures.
11. The method of claim 10 wherein the predetermined range of
temperatures has a lower limit higher than the ambient temperature
at the surface.
12. The method of claim 11 wherein the predetermined range of
temperatures has an upper limit lower than the ambient temperature
in the wellbore.
13. The method of claim 9 wherein regulating the temperature within
the insulated chamber further comprises: increasing the temperature
within the insulated chamber when temperature within the chamber is
below the predetermined range; and decreasing the temperature
within the insulated chamber when the temperature within the
chamber is above the predetermined range.
14. The method of claim 9 wherein the temperature control system
comprises a thermoelectric cooler.
15. The method of claim 9 wherein the temperature control system is
only activated when the temperature-sensitive electronic device is
needed to perform a selected function.
16. The method of claim 9 wherein intermittently activating the
temperature control system further comprises: not regulating the
temperature within the insulated chamber; activating the
temperature control system to reduce the temperature within the
insulated chamber so that the temperature-sensitive electronic
component can perform a selected function; and deactivating the
temperature control system.
17. A downhole electronic assembly comprising: a
temperature-sensitive electronic component; a temperature-tolerant
electronic component in electrical communication with said
temperature-sensitive electronic component; an insulating chamber
providing a thermal barrier between said temperature-sensitive
electronic component and said temperature-tolerant electronic
component; and a temperature control apparatus in thermal
communication with said temperature-sensitive component.
18. The electronic assembly of claim 17 wherein said temperature
control apparatus further comprises: a temperature sensor operable
to measure the temperature within said insulating chamber; a
thermostat operable to receive the measured temperature from said
temperature sensor; and a thermodynamic device coupled to said
thermostat and in thermal communication with said
temperature-sensitive component.
19. The electronic assembly of claim 18 wherein said temperature
control apparatus further comprises a switching amplifier or a
variable switch-mode power supply coupled to said thermostat and to
said thermodynamic device.
20. The electronic assembly of claim 18 wherein said temperature
control apparatus further comprises a switching amplifier coupled
to said thermostat and to said thermodynamic device.
21. The electronic assembly of claim 18 wherein said thermodynamic
device is a thermoelectric cooler.
22. The electronic assembly of claim 17 wherein said temperature
control apparatus is operable to maintain the temperature within
said insulating chamber within a range of temperatures.
23. The electronic assembly of claim 17 wherein said temperature
control apparatus is operable to selectively regulate the
temperature of said temperature-sensitive component when performing
a temperature-limited function.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND
[0003] The present invention relates generally to methods and
apparatus for operating electronic components on a downhole tool
within a wellbore. More particularly, the present invention relates
to methods and apparatus for controlling the temperature of
downhole electronic components.
[0004] Many wellbore logging and evaluation tools utilize
electronic components to gather data from the wellbore and
surrounding formation and transmit that data back to the surface.
Because the temperature within a wellbore increases with depth,
these electronic components are routinely exposed to very high
ambient temperatures. The temperature of the electronic components
is also increased by the consumption and production of power by the
electronic components themselves.
[0005] Many of these electronic components may be temperature
sensitive components that may face degrading performance with
increasing temperatures. Further, some of the electronic components
may only satisfactorily operate within a certain range of
temperatures. Therefore, as the complexity and sophistication of
the electronic components disposed within downhole tools increases,
methods and apparatus for cooling these components take on greater
importance.
[0006] Several downhole electronic component cooling systems have
been developed that use an array of temperature control
technologies. Some of these systems are passive systems that seek
to insulate the electronic components to delay the inevitable
temperature increase. These passive systems extend the operating
life of the tool but may or may not provide sufficient operating
life to accomplish the desired analysis.
[0007] Active systems are also available that cool the electronic
components through refrigeration or some other temperature control
technique. Active systems require a source of power, such as a
supply of chilled fluid from the surface or electricity from a
battery or turbine located downhole. The sources of power are often
limited and the power consumed by the cooling system reduces the
power available to the electronic components to perform the desired
monitoring.
[0008] There remains a need to develop more efficient methods and
apparatus for controlling the temperature of downhole electronic
components that overcome some of the foregoing difficulties while
providing more advantageous overall results.
SUMMARY OF THE PREFERRED EMBODIMENTS
[0009] The problems noted above are solved in a large part by
apparatus and methods for operating an electronics assembly of a
downhole tool. A method comprises disposing a temperature-sensitive
electronic component within an insulated chamber contained within a
downhole tool. The temperature of the temperature-sensitive
electronic component is monitored and a temperature control system
is selectively activated to regulate the temperature of the
temperature-sensitive electronic component. A downhole electronic
assembly comprises a temperature-sensitive electronic component and
a temperature-tolerant electronic component in electrical
communication with the temperature-sensitive electronic component.
An insulating chamber provides a thermal barrier between the
temperature-sensitive electronic component and the
temperature-tolerant electronic component. A temperature control
apparatus in thermal communication with the temperature-sensitive
component.
[0010] Thus, the present invention comprises a combination of
features and advantages that enable it to overcome various problems
of prior devices. The various characteristics described above, as
well as other features, will be readily apparent to those skilled
in the art upon reading the following detailed description of the
preferred embodiments of the invention, and by referring to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more detailed description of the preferred embodiment
of the present invention, reference will now be made to the
accompanying drawings, wherein:
[0012] FIG. 1 is an illustration of a drilling rig including a
measurement while drilling tool;
[0013] FIG. 2 is a schematic illustration of an electronic assembly
of a downhole tool; and
[0014] FIG. 3 is a schematic illustration of a cooling system
constructed in accordance with embodiments of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Referring now to FIG. 1, a drilling rig 10 supports and
drives a drill string 12 to form a wellbore 14. Located at the
distal end of drill string 12 is a bottom hole assembly 16
comprising drill bit 18 and monitoring tool 20. Monitoring tool 20
includes power supply 22 and electronics module 24. Electronics
module 24 includes data acquisition module 26 and data storage and
transfer module 28. Acquisition module 26 gathers data, such as
seismic data or pressure data, from wellbore 14 and/or the
surrounding formation. This data is stored in storage and transfer
module 28 and communicated to surface module 30, via cable
connections, sonic signals, or wireless telemetry.
[0016] Referring now to FIG. 2, electronics assembly 200 is shown
including power supply 202, temperature-tolerant electronic
component 204, temperature-sensitive electronic component 206, and
temperature control system 208. Temperature-sensitive electronic
component 206 is isolated within insulated chamber 210. Temperature
control system 208 includes temperature sensor 212, temperature
regulator 214, and controller 216. Sensor 212 and regulator 214 are
partially disposed within, or in thermal communication with,
insulated chamber 210. Controller 216 may be located outside of
chamber 210.
[0017] Temperature-tolerant component 204 includes those
electronics that have operating envelopes including relatively high
temperatures and those components that tend to generate large
amounts of heat during operation. Temperature-sensitive component
206 includes one or more components that have operating
characteristics significantly dependent on temperature. This
temperature dependence may be manifested in a variety of ways,
including a degradation of performance, an inability to fully
function, and a limitation on stability.
[0018] In operation, controller 216 monitors the temperature inside
chamber 210 via sensor 212. Controller 216 operates regulator 214
that adds or removes heat from chamber 210 in order to maintain a
desired temperature for temperature-sensitive component 206. Once
the temperature within chamber 210 reaches a desired level,
controller 216 shuts down regulator 214. Regulator 214 may be
periodically activated to keep the temperature within chamber 210
within a desired range. By isolating temperature-sensitive
component 206 within chamber 210, the mass of the temperature
controlled components and the required heating load can be
reduced.
[0019] Assembly 200 may include one or more chambers 210 isolating
separate temperature-sensitive components 206. Each separate
chamber 210 may have its own temperature control system 208 such
that each temperature-sensitive component 206 can be maintained
within a selected temperature range independent of the temperature
ranges for the other components.
[0020] Referring now to FIG. 3, temperature control assembly 300 is
shown including temperature-sensitive component 302, thermoelectric
cooler 304, heat sink 306, insulated chamber 308, temperature
sensor 310, thermostat 312, and amplifier 313.
Temperature-sensitive component 302 is disposed within insulated
chamber 308 and in thermal contact with thermoelectric cooler 304.
Heat sink 306 is located outside of insulated chamber 308 and in
thermal contact with thermoelectric cooler 304. Thermostat 312
monitors the temperature within chamber 308 via sensor 310 and
provides power to thermoelectric cooler 304 through amplifier 313
and electrical connection 314. Amplifier 313 may be a class-D
amplifier, liner amplifier, variable switch-mode power supply, or a
switching amplifier.
[0021] Thermoelectric cooler 304 is a Peltier-type device
comprising p-type semiconductor 316 and n-type semiconductor 318
sandwiched between two conductive plates 320, 322. Semiconductors
316, 318 are connected electrically in series and thermally in
parallel. Conductive plates 320, 322 have a high thermal
conductivity and are often a ceramic material, such as a metallized
beryllium oxide and/or an aluminum oxide. In certain embodiments,
conductive plate 320 may be integrated into component 302. A DC
voltage is applied through electrical connection 314.
[0022] A positive DC voltage applied to n-type semiconductor 318
causes electrons to pass from p-type semiconductor 316 to n-type
semiconductor 318. As these electrons pass to n-type semiconductor
318 they absorb heat, essentially causing heat to flow from
conductive plate 320 to conductive plate 322. This, in effect, acts
as a heat pump, transferring heat from temperature-sensitive
component 302 to heat sink 306.
[0023] A negative DC voltage applied to n-type semiconductor 318
has the reverse effect and causes electrons to pass from n-type
semiconductor 318 to p-type semiconductor 316. As these electrons
pass to p-type semiconductor 316 they absorb heat, essentially
causing heat to flow from conductive plate 322 to conductive plate
320. This, in effect, acts as a heat pump, transferring heat to
temperature-sensitive component 302 from heat sink 306.
[0024] Semiconductors 316, 318 may be fabricated from an alloy of
bismuth, telluride, selenium, and antimony and may be doped and
processed to yield polycrystalline semiconductors with anisotropic
thermoelectric properties. A plurality of thermoelectric coolers
304 may be stacked in a multistage or cascading arrangement to
increase the potential thermal transfer through the cooler.
[0025] Temperature control assembly 300 can be operated in a first
mode where thermostat 312 is utilized to maintain the temperature
within chamber 308 within a selected temperature range. For
example, temperature-sensitive component 302 may be a temperature
compensated zener diode being used as a voltage reference in a
downhole application. Further, the zener diode may be specifically
constructed to have a zero temperature coefficient (ZTC) at or near
150.degree. C., normally the ZTC point is engineered to occurs at
approximately 25.degree. C. or ambient room temperature.
[0026] Thermostat 312 is used to control the environment of the
zener diode and other temperature sensitive components within
chamber 308. Thermostat 312 senses the temperature within chamber
308 via sensor 310 and operates thermoelectric cooler 304 to
maintain the temperature at 150.degree. C.+/-2.degree. C. As
operation of the downhole tool is initiated, the temperature within
chamber 308 can be increased to within the desired range by
operating thermoelectric cooler 304 as a heater. Once the tool is
downhole and subjected to higher ambient temperatures, the
thermoelectric cooler 304 can be operated as a cooler to maintain
the temperature within the desired range.
[0027] Operation in this mode allows the temperature sensitive
components to operate at a relatively constant temperature and
effectively shifts much of the burden of stabilization to the
accuracy of the thermostat and thus away from having to perform
higher order curvature corrections. Regulating the temperature of
the selected components provides an efficient and cost effective
way of stabilizing the output voltages of the zener diode voltage
reference without any high order curvature correction schemes.
[0028] Temperature control assembly 300 can also be operated in a
second mode where thermostat 312 is utilized to intermittently
maintain the temperature within chamber 308 within a selected
temperature range. For example, temperature-sensitive component 302
may be a memory storage component in a downhole application. Many
memory components can effectively store data at higher temperatures
than are allowable for reading and writing to the memory.
[0029] Thermostat 312 can be used to control the environment of the
memory components within chamber 308. Thermostat 312 senses the
temperature within chamber 308 via sensor 310. When data is ready
to be written to, or read from, the memory thermoelectric cooler
304 is operated to reduce the temperature to within the allowable
range. Once the read/write process is complete, thermoelectric
cooler 304 is deactivated and the temperature within chamber 308 is
allowed to increase.
[0030] Batch cooling the memory modules in this manner allows for
more efficient use of power from a limited supply of power often
associated with a downhole application. This batch cooling method
could also be used with a voltage reference to cool the reference
only when being used or with a calibration reference that benefits
from being calibrated to a controlled temperature. Batch cooling
methods could also be used with other temperature control and
refrigeration systems and are not limited to use with
thermoelectric coolers.
[0031] While preferred embodiments of this invention have been
shown and described, modifications thereof can be made by one
skilled in the art without departing from the scope or teaching of
this invention. The embodiments described herein are exemplary only
and are not limiting. Many variations and modifications of the
system and apparatus are possible and are within the scope of the
invention. For example, the relative dimensions of various parts,
the materials from which the various parts are made, and other
parameters can be varied, so long as the apparatus retain the
advantages discussed herein. Accordingly, the scope of protection
is not limited to the embodiments described herein, but is only
limited by the claims that follow, the scope of which shall include
all equivalents of the subject matter of the claims.
* * * * *