DOWNHOLE TELEMETRY TOOL WITH ADAPTIVE FREQUENCY TRANSMITTER

摘要

A method for selecting a drilling fluid pressure pulse transmission frequency in a downhole telemetry tool comprises: emitting a frequency sweep wave in a drilling fluid that comprises pressure pulses over a range of frequencies and over a period of time; measuring a pressure of the drilling fluid at the telemetry tool while the frequency sweep wave is being emitted; determining a signal strength at each frequency in the range of frequencies from the measured pressure of the drilling fluid; and selecting at least one frequency in the range of frequencies that meets a selected signal strength threshold as a telemetry signal transmission frequency for the telemetry tool. The method can further comprise encoding the at least one selected frequency in a header message and transmitting the header message to surface using pressure pulse telemetry, and then encoding telemetry data into a pressure pulse telemetry signal and transmitting the pressure pulse telemetry signal to surface at the at least one selected frequency.