Abstract: An acoustic source and a spaced-apart acoustic receiver are moved through the casing of a well. Electrical signals indicative of the source signal and the receiver signal are applied uphole by way of a conductor to a time series analyzer and recorder. The time series analyzer provides power-spectral density functions and cross-spectral density functions of the source and receiver signals during reconnaissance logging operations. From these functions there is determined the ability of the casing-cement formation combination to transmit the source signal to the receiver and also the linear correlation of the source signal and receiver signal.

Abstract: A pair of acoustic detectors are moved through a well to detect sound at various levels within the well. Electrical signals indicative of the detected sound are applied from the acoustic detectors by way of a conductor cable to uphole recording equipment including an amplifier, spectrum analyzer, crosscorrelator, and recorder. The spectrum analyzer provides frequency spectrums of the amplified signals from the acoustic detectors. The crosscorrelator provides an indication of the time differential between the traveltimes of acoustic noise to the acoustic detectors for use in the location of flow leaks through or behind the well casing.

Abstract: An acoustic detector is moved through a well to detect sound at various levels within the well. An electrical signal indicative of the detected sound is applied from the acoustic detector by way of a conductor cable to uphole recording equipment including an amplifier, spectrum analyzer, and recorder. The spectrum analyzer provides a frequency spectrum of the amplified signal from the acoustic detector. This frequency spectrum is recorded for use in the identification of flow leaks through or behind the casing of the well in accordance with predetermined spectrum analysis characteristics of single-phase gas and single-phase liquid leaks.