Patent ID: 6747569
Filing Date: 2004-06-08
Classification: E21B,G01V

Abstract:
A downhole telemetry and power system for use with a borehole extending into a formation, the borehole including a casing positioned within the borehole and a piping structure contained within the casing, the system comprising:a surface choke coupled to the piping structure; a surface system including a data source providing data to be transmitted, a power amplifier coupled to the data source and to an external power source, the power amplifier having an output electrically coupled to the casing and the piping structure downhole from the surface choke, the power amplifier operative to provide a power signal having a first frequency and to modulate, in a first modulation scheme, the power signal with the data to be transmitted, wherein the first frequency of power signal is selected as a function of the depth of the borehole; a downhole choke having a first inductance, the downhole choke disposed downhole a predetermined distance within the borehole and disposed coaxially about the piping structure, wherein the first inductance is selected as a function of the depth of the borehole; a downhole system including a power supply electrically coupled to the downhole choke, the power supply configured and arranged to receive at least a portion of the modulated power signal and to provide at least one output voltage, the downhole system further including a receiver electrically coupled to the choke coil and configured and arranged to demodulate the modulated power signal to recover the data to be transmitted.