Remote actuation of downhole tools using fluid pressure from surface

摘要

An apparatus for and a method of transmitting signals from the surface of a well to a location downhole in the well utilize a downhole fluid pressure sensor (52), a signal processing means (54; 56; 58) located downhole in electrical connection with the pressure sensor (52) and a downhole programmable logic unit (60) capable of counting at least two signals received by the downhole pressure sensor (52). Typically, signals transmitted from the surface comprise a peak in pressure of downhole fluid located in production tubing run into a well bore and these signals are sensed by the downhole fluid pressure sensor (52). The logic unit (60) outputs a signal to a tool to be actuated if it receives a number of signals within a particular time period, wherein the logic unit (60) actuates the tool by the frequency of signals received rather than the amplitude of the signals received.