Process and device for generating signals which can be transmitted in a well

Abstract

In a process for generating signals which can be transmitted from above ground to a receiver located below ground in a well, the volume flow of a fluid pump ( 1 ) arranged above ground, which conveys fluid from a fluid tank ( 8 ) through the interior of a drill string to the bottom of a well, is temporally changed. The temporal change of the volume flow of the fluid pump ( 1 ) is caused by a change of the drive speed of the fluid pump ( 1 ), with the drive speed not falling below a minimum speed for maintaining a minimum volume flow.

1 . A method for transmitting signals from above ground to a receiver located below: ground in a well, the method comprising: 
 temporarily changing the drive speed of an above-ground fluid pump that conveys fluid to a bottom of a well through an interior portion of a drill string, thereby changing the volume flow of the fluid pump;    wherein the change of volume flow comprises a signal detectable by the receiver located below ground in the well; and    wherein the drive speed is maintained above a minimum speed so as to maintain a minimum fluid flow.    
   
   
       2 . The method of  claim 1 , wherein the temporary changes of the drive speed of the fluid pump are synchronized to maintain a constant average fluid flow.  
   
   
       3 . The method of  claim 1 , wherein the temporary changes of the drive speed of the fluid pump have a frequency of less than  1  Hertz.  
   
   
       4 . The method of  claim 1  wherein the pump is a reciprocating pump.  
   
   
       5 . The method of  claim 1  wherein the pump is driven by an electric motor.  
   
   
       6 . The method of  claim 1  wherein the pump is driven by a diesel engine.  
   
   
       7 . The method of  claim 6  wherein the diesel engine speed is varied to change the drive speed of the pump.  
   
   
       8 . The method of  claim 6  wherein a hydraulic converter is used to change the drive speed of the pump.  
   
   
       9 . A device for transmitting signals from above ground to a receiver located below ground in a well, the device comprising: 
 an above-ground fluid pump that conveys fluid to a bottom of a well through an interior portion of a drill string;    a value transmitter adapted to modulate a drive speed of the fluid pump, thereby changing the volume flow of the fluid pump, in response to a signal intended for transmission to the receiver located below ground in the well;    wherein the change of volume flow comprises a signal detectable by the receiver located below ground in the well; and    wherein the drive speed is maintained above a minimum speed so as to maintain a minimum fluid flow.    
   
   
       10 . The device of  claim 9 , wherein the signal intended for transmission to the receiver located below ground in the well is generated by a manually operable voltage divider.  
   
   
       11 . The device of  claim 9 , wherein the signal intended for transmission to the receiver located below ground in the well is generated by an analog curve shape generator.  
   
   
       12 . The device of  claim 9 , wherein the signal intended for transmission to the receiver located below ground in the well is generated by a computer that generates the modulation via software.  
   
   
       13 . The device of  claim 12  wherein the computer emits said modulation as an analog signal.  
   
   
       14 . The device of  claim 12  wherein the computer emits said modulation as a digital signal.  
   
   
       15 . The device of  claim 9  wherein the pump is a reciprocating pump.  
   
   
       16 . The device of  claim 9  wherein the pump is driven by an electric motor.  
   
   
       17 . The device of  claim 9  wherein the pump is driven by a diesel engine.  
   
   
       18 . The method of  claim 17  wherein the diesel engine speed is varied to change the drive speed of the pump.  
   
   
       19 . The method of  claim 17  wherein a hydraulic converter is used to change the drive speed of the pump.  
   
   
       20 . A device for transmitting signals from above ground to a receiver located below ground in a well, the device comprising: 
 an above-ground fluid pump that conveys fluid to a bottom of a well through an interior portion of a drill string; and    means for varying the speed of the fluid pump, thereby changing the volume flow of the fluid pump, whereby the changing volume flow comprises a signal to the receiver.