Patent ID: 9013955
Filing Date: 2015-04-21
Classification: E21B

Abstract:
1. A method of characterizing cement in proximity to a casing installed in a borehole in an earth formation, the method comprising: activating a transducer at at least one azimuthal orientation in the borehole and generating an acoustic pulse; receiving a signal comprising a plurality of overlapping events resulting from the generation of the acoustic pulse, at least one of the plurality of overlapping events being due to a ringing of the transducer; estimating an envelope of the received signal; and estimating from the envelope of the received signal an arrival time of each of the plurality of events by, at least in part, applying a Gaussian Laplace operator to the envelope to estimate arrival times, the arrival times being characteristic of a property of the cement in proximity to the casing, the property being an acoustic impedance of the cement in proximity to the casing.