摘要 |
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.
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