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.

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.