Patent ID: 8151905
Filing Date: 2012-04-10
Classification: E21B

Abstract:
1. A downhole telemetry system for use in a wellbore including borehole fluid, the system including: a stator including flow channels; a rotor including flow channels and rotatable relative to the stator, wherein the rotor is coupled to a drive shaft and is configured to drive the rotation of the drive shaft in response to the flow of borehole fluid through the rotor; the rotation of the rotor relative to the stator configured to create pressure variations in the borehole fluid related to the movement of the rotor channels relative to the stator channels, the pressure variations forming a carrier wave; a regulating system configured to adjust the amount of fluid force on the rotor for a given flow rate of borehole fluid through the rotor to maintain the frequency of the carrier wave within a range of a target frequency; an alternator drivable by the rotation of the drive shaft to provide power to the system; and an encoder configured to adjust the rotation of the rotor to modulate the carrier wave.