CPC E21B 47/13 (2020.05) [E21B 21/08 (2013.01); E21B 47/18 (2013.01); H04L 25/028 (2013.01); H04L 27/02 (2013.01); H04L 27/10 (2013.01); H04L 27/18 (2013.01); H04L 27/34 (2013.01); E21B 47/0228 (2020.05); E21B 47/06 (2013.01); E21B 47/07 (2020.05); E21B 49/00 (2013.01)] | 11 Claims |
1. A method comprising:
receiving, by a signal modulator, direct current (DC) from an electrical power supply, the signal modulator comprising: a first reactive circuit and a second reactive circuit; a first output terminal and a second output terminal for direct or inductive connection to the transmission medium at separate, spaced-apart locations; and a plurality of switches being controlled by the controller to alternatingly switch the signal modulator between a first configuration and a second configuration;
receiving, by the signal modulator, controlling commands from a controller;
transmitting, by the signal modulator, at least one electromagnetic (EM) telemetry signal in response to the controlling commands, the at least one EM telemetry signal transmitted through a transmission medium between a surface location and an underground location or between the underground location and another underground location,
wherein transmitting the at least one EM telemetry signal comprises:
operating the signal modulator in the first configuration, such that an input of the first reactive circuit is at least intermittently connected to the power supply, an output of the first reactive circuit is connected to the first output terminal, and the second output terminal is connected to an electrical return path which bypasses the second reactive circuit; and
at another time, operating the signal modulator in the second configuration, such that an input of the second reactive circuit is at least intermittently connected to the power supply, an output of the second reactive circuit is connected to the second output terminal, and the first output terminal is connected to another electrical return path which bypasses the first reactive circuit, optionally each of the first reactive circuit and the second reactive circuit comprises at least one inductor, at least one capacitor, or at least one inductor and at least one capacitor.
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