Switches for controlling downhole tools

Abstract

A downhole tool for time delaying a downhole activity. The downhole tool includes a housing having a bore; a moving sleeve configured to move relative to the housing; an electronic valve configured to open and close when receiving an electrical signal; and a switch that is responsive to a fluid pressure inside the bore. The downhole tool electronically counts down a set time.

1 . A downhole tool for time delaying a downhole activity, the downhole tool comprising:
 a housing having a bore;   a moving sleeve configured to move relative to the housing;   an electronic valve configured to open and close when receiving an electrical signal; and   a switch that is responsive to a fluid pressure inside the bore,   wherein the downhole tool electronically counts down a set time.   
     
     
         2 . The tool of  claim 1 , wherein the switch is configured to close an electrical circuit to energize an electronic block. 
     
     
         3 . The tool of  claim 2 , wherein the switch is electrically wired to the electronic block. 
     
     
         4 . The tool of  claim 3 , wherein the electronic valve is electrically wired to the electronic block. 
     
     
         5 . The tool of  claim 4 , wherein the electronic block includes a timer that counts down the set time. 
     
     
         6 . The tool of  claim 5 , wherein the timer counts down the set time after being energized and sends a command to a dump valve of the electronic valve to open. 
     
     
         7 . The tool of  claim 6 , wherein the electronic valve, when opened, allows a fluid from the bore to reach the moving sleeve and move the moving sleeve. 
     
     
         8 . The tool of  claim 5 , wherein the electronic block includes a power source. 
     
     
         9 . The tool of  claim 1 , wherein the switch includes a biasing mechanism that resets the switch. 
     
     
         10 . The tool of  claim 1 , wherein the switch includes a first pressure responsive switch and a second, resettable, pressure responsive switch. 
     
     
         11 . The tool of  claim 1 , wherein the switch includes a first pressure responsive switch and a second switch that includes a pressure transducer. 
     
     
         12 . The tool of  claim 1 , wherein the switch includes a first pressure responsive switch and a second switch that includes a velocity transducer. 
     
     
         13 . The tool of  claim 1 , wherein the tool is a toe valve. 
     
     
         14 . The tool of  claim 1 , wherein the tool is a setting tool. 
     
     
         15 . A switch-valve assembly to actuate a downhole tool, the switch-valve assembly comprising:
 a switch located to have a part exposed to a fluid pressure associated with the downhole tool;   an electronic block electrically connected to the switch; and   an electronic valve electrically connected to the electronic block and configured to open and close when receiving an electrical signal from the electronic block,   wherein the electronic block counts down a set time.   
     
     
         16 . The assembly of  claim 15 , wherein the switch is configured to close an electrical circuit to energize the electronic block. 
     
     
         17 . The assembly of  claim 15 , wherein the switch includes a biasing mechanism that resets the switch. 
     
     
         18 . The assembly of  claim 15 , wherein the switch includes a first pressure responsive switch and a second, resettable, pressure responsive switch. 
     
     
         19 . The assembly of  claim 15 , wherein the switch includes a first pressure responsive switch and a second switch that includes a pressure transducer. 
     
     
         20 . The assembly of  claim 15 , wherein the switch includes a first pressure responsive switch and a second switch that includes a velocity transducer. 
     
     
         21 . A method for actuating a downhole tool in a wellbore, the method comprising:
 lowering the downhole tool into the wellbore;   increasing a pressure into the wellbore above a threshold pressure of a pressure responsive switch to close the switch;   energizing an electronic block associated with the pressure responsive switch;   starting a timer of the electronic block; and   sending a command from the electronic block to an electronic valve at the end of a set time of the timer.   
     
     
         22 . The method of  claim 21 , further comprising:
 decreasing the pressure into the wellbore to open the switch.   
     
     
         23 . The method of  claim 22 , further comprising:
 resetting the timer when the switch is opened.