Gas cut detection based ultrasonic receiving circuit

• Main Authors: GU JUN, ZHAN HUIQIN, GUAN JIANGTAO, GU TIANXIANG
• Format: Patent
• Language: Chinese; English
• Published: 21.11.2017
• Subjects: BASIC ELECTRONIC CIRCUITRY; CONTROL OF AMPLIFICATION; EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; ELECTRICITY; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS

The invention discloses a gas cut detection based ultrasonic receiving circuit. As a gas cut signal is a non-stationary signal and the statistical distribution thereof is unfixed no manner in a time domain or in a frequency domain, problem such as gas cut signal distortion, detection sensitivity reduction and circuit frequency band limitation are resulted. Aiming at the problems, the ultrasonic receiving circuit of a low-noise pre-amplifier and a low-noise post-amplifier of programmable gain amplification, an intermediate amplifier between the low-noise pre-amplifier and the post-amplifier, and locked amplifier is provided. A microcontroller collects signal amplitudes output by the low-noise pre-amplifier and the low-noise post-amplifier respectively, adjusts two-stage amplification gains automatically based on size assessment of the signal amplitudes, realizes accurate extraction of a Doppler frequency deviation signal (the gas cut signal) which reflects the gas cut degree. Therefore, the problems, including