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 . Process for generating signals which can be transmitted from above ground to a receiver located below ground in a well, wherein the volume flow of a fluid pump arranged above ground, which conveys fluid from a fluid tank through the interior of a drill string to the bottom of a well, is temporally changed, and wherein the temporal change of the volume flow of the fluid pump is caused by a change of the drive speed of the fluid pump, with the drive speed not falling below a minimum speed for maintaining a minimum volume flow.  
     
     
         2 . Process according to  claim 1 , characterised in that after reduction of the drive speed of the fluid pump, the drive speed is temporarily increased above the normal value set before the reduction.  
     
     
         3 . Process according to  claim 2 , characterised in that the temporal changes of the drive speed of the fluid pump are synchronised with one another in such a way that the volume flow of the fluid pump is on average constant.  
     
     
         4 . Process according to  claim 1 , characterised in that the temporal changes of the drive speed of the fluid pump have a frequency of less than 1 hertz.  
     
     
         5 . Process according to  claim 1 , characterised in that the temporal changes of the drive speed of the fluid pump result from a temporal change of the desired value of a control or regulating device for controlling or regulating the drive speed.  
     
     
         6 . Process according to  claim 1 , characterised in that the temporal changes have a trapezoidal shape.  
     
     
         7 . Process according to  claim 1 , characterised in that the temporal changes have a sinusoidal shape.  
     
     
         8 . Device for generating signals which can be transmitted from above ground to a receiver located below ground in a well, comprising: 
 a fluid pump arranged above ground, which conveys fluid from a fluid tank through the interior of a drill string to the bottom of a well,    a desired value transmitter for adjusting the drive speed of the fluid pump,    a signal generator for generating signals, which are intended for transmission to a receiver located below ground in a well, and    an interface which temporally changes the desired value set at the desired value transmitter as a function of the signals of the signal generator.    
     
     
         9 . Device according to  claim 8 , characterised in that the signal generator is a manually operable voltage divider.  
     
     
         10 . Device according to  claim 8 , characterised in that the signal generator is an analog curve shape generator.  
     
     
         11 . Device according to  claim 8 , characterised in that the signal generator is a computer which generates the required modulation via software and emits said modulation via digital/analog conversion as electric analog voltage or directly as a digital signal.  
     
     
         12 . Device according to  claim 8 , wherein the interface comprises an input for an electric desired value, an input for an electric modulation signal, a signal processing stage for processing the modulation signal, and a multiplier stage for linking the processed modulation signal with the electric desired value to a desired value change which is present at an output.  
     
     
         13 . Device according to  claim 8 , wherein the interface comprises an input for a hydraulically or pneumatically transmitted desired value, an input for an electric modulation signal, electrically controlled proportional valves for changing the hydraulically or pneumatically transmitted desired value, an electric control device for controlling the proportional valves as a function of the modulation signal and an output for the changed hydraulic or pneumatic desired value.  
     
     
         14 . Process for generating signals which can be transmitted from above ground to a receiver located below ground in a well, wherein the angular velocity of a rotatably-driven drill string located in the well is temporally changed.  
     
     
         15 . A device for executing the process according to  claim 14  with a rotary drive located above ground for rotatably driving a drill string and with a desired value transmitter for adjusting the drive speed of the rotary drive, wherein a signal generator for generating signals, which are intended for transmission to a receiver below ground located in a well, and an interface which temporally changes the desired value set at the desired value transmitter as a function of the signals of the signal generator.  
     
     
         16 . Device according to  claim 15 , wherein the interface comprises an input for an electric desired value, an input for an electric modulation signal, a signal processing stage for processing the modulation signal, and a multiplier stage for linking the processed modulation signal with the electric desired value to a desired value change which is present at an output.  
     
     
         17 . Device according to  claim 15 , wherein the interface comprises an input for a hydraulically or pneumatically transmitted desired value, an input for an electric modulation signal, electrically controlled proportional valves for changing the hydraulically or pneumatically transmitted desired value, an electric control device for controlling the proportional valves as a function of the modulation signal and an output for the changed hydraulic or pneumatic desired value.