Communication method for untethered downhole systems

Abstract

The disclosure provides methods of communication for untethered systems. The method includes defining a window for sampling a torque-related current and a modulator rotor relative position-related parameter; using the defined window, recording local maximum and local minimum values of the torque-related current versus a modulator rotor relative position-related parameter of a rotor of a rotary pulser system in the untethered system; identifying at least one of consecutive torque-related current minimum values and consecutive torque-related current maximum values based on a periodicity; computing an absolute modulator rotor position based on the periodic maxima and minima of the torque-related current; and controlling the modulator rotor using the absolute modulator rotor position to modulate uplink signals to a surface environment.

Dependencies are inferred from the claim text.