Abstract: A method and apparatus to measure the fluid depth in a well or borehole is described. The approach reduces the effects of acoustic noise occurring near the top of the well or borehole that can interfere with the fluid depth measurement. A resonant acoustic structure between an acoustic transducer and the well or borehole provides efficient coupling of spectrally narrow acoustic signals into the well or borehole, as well as providing a bandpass acoustic filter on the returning signal, to improve the signal to noise ratio of the desired acoustic reflection.

Abstract: A method to measure the fluid depth in a wellbore is described. An optimized acoustic pulse stream is launched into the wellbore, and the round-trip time-of-flight between the fluid surface and the top of the wellbore is measured. The method provides improved signal to noise ratio, and can be actively tuned to a plurality of wellbore configurations.

Abstract: A method and apparatus to measure the fluid depth in a well or borehole is described. The approach reduces the effects of acoustic noise occurring near the top of the well or borehole that can interfere with the fluid depth measurement. A resonant acoustic structure between an acoustic transducer and the well or borehole provides efficient coupling of spectrally narrow acoustic signals into the well or borehole, as well as providing a bandpass acoustic filter on the returning signal, to improve the signal to noise ratio of the desired acoustic reflection.

Abstract: A method to measure the fluid depth in a wellbore is described. An optimized acoustic pulse stream is launched into the wellbore, and the round-trip time-of-flight between the fluid surface and the top of the wellbore is measured. The method provides improved signal to noise ratio, and can be actively tuned to a plurality of wellbore configurations.