Systems and Methods for Downhole Communications Using Power Cycling

Abstract

Systems and methods for using power cycle events to cause a downhole tool to change its operational state and/or transmit a data stream to the downhole tool. In one embodiment, a tool such as a gauge for an ESP is positioned downhole in a well and is configured to receive power from a control unit at the surface of the well. The control unit power cycles the downhole tool to communicate a need to modify the operational state of the tool. The tool may include a non-volatile memory to store an indicator of the tool's current operational state. When the tool is power cycled, the operational state is modified and the indicator is updated. The power cycling may cause the tool to increment through available operational states, or the timing of the power cycles may convey parameters or other operating information to the downhole tool.

1 . A system comprising:
 control equipment positioned at the surface of a well;   a downhole tool positioned within the wellbore of the well; and   a power cable coupled between the control equipment and the downhole tool;   wherein the downhole tool is configured to receive power through the power cable;   wherein the control equipment is configured to control the delivery of power through the power cable to the downhole tool and to thereby selectively power cycle the downhole tool; and   wherein the downhole tool is configured to modify operation of the downhole tool in response to being power cycled.   
     
     
         2 . An apparatus comprising:
 a downhole tool configured to be positioned within the wellbore of a well;   wherein the downhole tool is configured to modify operation of the downhole tool in response to power cycle events.   
     
     
         3 . The apparatus of  claim 2 , wherein the downhole tool includes a non-volatile memory, wherein the downhole tool is configured to store at least one operational state of the downhole tool, wherein the downhole tool is configured to modify the at least one operational state in response to the power cycle events. 
     
     
         4 . The apparatus of  claim 3 , wherein the non-volatile memory stores a plurality of operational states, wherein modifying the at least one operational state comprises operating in a first one of the plurality of operational states and then operating in a different one of the plurality of operational states. 
     
     
         5 . The apparatus of  claim 4 , wherein the downhole tool is configured to increment between the operational states in response to the power cycle events. 
     
     
         6 . The apparatus of  claim 4 , wherein a first function performed in the first one of the plurality of operational states is different from a second function performed in the different one of the plurality of operational states. 
     
     
         7 . The apparatus of  claim 4 , wherein a first function is performed in both the first and different ones of the plurality of operational states, wherein the downhole tool operates using a first set of operating parameters in the first operational state and a different set of operating parameters in the different one of the plurality of operational states. 
     
     
         8 . The apparatus of  claim 2 , wherein the downhole tool is configured to determine one or more timing associated with successive power cycle events, identify one or more modifications of the operation of the downhole tool corresponding to the delays, and implement the one or more modifications in the operation of the downhole tool. 
     
     
         9 . The apparatus of  claim 8 , wherein the one or more modifications comprise a state change. 
     
     
         10 . The apparatus of  claim 8 , wherein the one or more modifications comprise changing one or more operating parameters of the downhole tool. 
     
     
         11 . The apparatus of  claim 10 , wherein the downhole tool is configured to selectively enter a state in which a number and power-on durations of subsequent power cycles are determined and interpreted as compressed data values. 
     
     
         12 . The apparatus of  claim 2 , wherein the downhole tool comprises a downhole gauge which is configured to sense one or more conditions downhole and to transmit data corresponding to the downhole conditions to equipment positioned at the surface of the well. 
     
     
         13 . A method implemented in a downhole tool, the method comprising:
 powering up a downhole tool and thereby causing the downhole tool to operate in a first operational state of the downhole tool; and   power cycling the downhole tool and thereby causing the downhole tool to operate in a second operational state which is different from the first operational state.   
     
     
         14 . The method of  claim 13 , wherein the downhole tool incorporates a non-volatile memory that stores a plurality of operational states including the first and second operational states. 
     
     
         15 . The method of  claim 14 , wherein the downhole tool increments between the plurality of operational states in response to detecting power cycle events. 
     
     
         16 . The method of  claim 14 , wherein in the first operational state, the downhole tool performs a first function, and in the second operational state, the downhole tool performs a second function which is different from the first function. 
     
     
         17 . The method of  claim 14 , wherein in both the first and second operational states, the downhole tool performs a first function, wherein in the first operational state, the downhole tool performs the first function using a first set of operating parameters, and in the second operational state, the downhole tool performs the first function using a second set of operating parameters which is different from the first set of operating parameters. 
     
     
         18 . The method of  claim 13 , further comprising determining one or more delays between successive power cycle events, identifying one or more modifications of the operation of the downhole tool corresponding to the delays, and implementing the one or more modifications in the second operational state. 
     
     
         19 . The method of  claim 18 , wherein the one or more modifications comprise changing the function of the downhole tool. 
     
     
         20 . The method of  claim 18 , wherein the one or more modifications comprise changing one or more operating parameters of the downhole tool. 
     
     
         21 . The method of  claim 20 , further comprising selectively placing the downhole tool in a state in which a number and power-on durations of subsequent power cycles are determined and interpreted as compressed data values. 
     
     
         22 . The method of  claim 13 , wherein the downhole tool comprises a downhole gauge, and wherein operate in at least one of the first and second operational states comprises sensing one or more conditions downhole and transmitting data corresponding to the downhole conditions to equipment positioned at the surface of a well.