US Patent 7392135 Adaptive equalization of downhole acoustic receivers

Methods and apparatus are provided for reducing and/or substantially eliminating sensitivity mismatch of acoustic receivers used with acoustic sources to determine acoustic properties of geologic formations as a logging tool traverses the formations. Methods are directed to detecting waveform arrival times at receivers, determining places in a well where arrival times of waves are substantially the same at a plurality of receivers, and estimating effective receiver sensitivities and equalization factors using Stoneley wave amplitudes and windowed deconvolution of Stoneley waves. Methods are further directed to correcting wave amplitudes using estimated effective receiver sensitivities and equalization factors for receivers.