Method for remote control of wellbore end devices

摘要

A method for controlling a remotely located wellbore tool 29 between modes of operation comprises securing to the wellbore conduit string 13 the electrically actuatable wellbore tool 29, an acoustic sensor 25 and a digital circuit for examining the sensor output to produce a control signal to actuate the tool 29 if it detects that a sensed acoustic signal from a transmitter at the surface has a frequency which has been assigned specifically to the relevant tool. The acoustic transmission comprises pressure pulses passing down a column 55 of wellbore fluid and has a frequency assigned before lowering the string 13 into position in the wellbore. Each tool has one or more assigned frequencies which are programmed into the digital receiver circuit by an operator, using a handset.