METHOD OF OPERATING A MUD PULSE TELEMETRY APPARATUS WITH A PRESSURE TRANSDUCER

摘要

A method of operating a dual pulse height fluid pressure pulse generator of a downhole measurement-while-drilling telemetry tool, the pulse generator operable to flow a drilling fluid in a full flow configuration to produce no pressure pulse, a reduced flow configuration to produce a high amplitude pressure pulse and an intermediate flow configuration to produce a low amplitude pressure pulse, the method comprising:
(a) operating the pulse generator to produce the no pressure pulse, the high amplitude pressure pulse and the low amplitude pressure pulse and measuring the pressures of the no pressure pulse, high amplitude pressure pulse and low amplitude pressure pulse;
(b) determining an amplitude of the high amplitude pressure pulse and an amplitude of the low amplitude pressure pulse from the measured pressures;
(c) comparing the determined amplitudes to a low amplitude reference pressure and a high amplitude reference pressure; and
(d) operating the pulse generator between the full and intermediate flow configurations in a low amplitude pulse mode to transmit a telemetry signal to surface only when the determined amplitude of the low amplitude pressure pulse is above the low amplitude reference pressure; or, operating the pulse generator between the full and reduced flow configurations in a high amplitude pulse mode to transmit a telemetry signal to surface only when the determined amplitude of the high amplitude pressure pulse is below the high amplitude reference pressure.