Patent ID: 6021095
Filing Date: 2000-02-01
Classification: E21B,Y10S

Abstract:
A method of controlling a remotely located wellbore tool between modes of operation, comprising:providing (a) an electrically-actuable wellbore tool, (b) an acoustic transmission sensor, and (c) a digital circuit for continually examining during monitoring operations detected acoustic transmissions and providing a control signal if said acoustic transmission defines a plurality of sequentially transmitted acoustic transmission segments each defining a particular predetermined actuation frequency;said digital circuit including:(a) a detection circuit communicatively coupled to said acoustic transmission sensor for generating a pulse signal corresponding to each one of said acoustic transmissions;(b) a counter circuit communicatively coupled to said detection circuit for counting said pulse signal; and(c) an enabling circuit for selectively enabling said counter circuit;(d) wherein said detection circuit, said counter circuit, and said enabling circuit cooperatively operate to cause the generation of said control signal;securing said electrically-actuable wellbore tool, said acoustic transmission sensor, and said digital circuit to a tubular conduit string;lowering said tubular conduit string within said wellbore to a selected wellbore location;providing a wellbore fluid column in contact with a portion of said tubular conduit but out of contact with said pressure sensor;generating an acoustic transmission in said wellbore fluid column which defines said plurality of sequentially transmitted acoustic transmission segments each defining a particular predetermined frequency; andproviding a control signal to said electrically-actuable wellbore tool when said digital circuit determines that said acoustic transmissions define said plurality of sequentially transmitted acoustic transmission segments each defining a particular predetermined frequency.