Method of determining depths of wellbore reflectors

A system for determining depth of wellbore reflectors by analyzing a pressure signal at a wellhead, the system comprising:

• a wellbore enabling performing a wellbore operation producing a pressure wave and its reflections from the wellbore reflectors;
• a wellbore high-frequency pressure sensor configured for registering a pressure wave and its reflections;
• a processing system configured to receive and automatically process data obtained by the pressure sensor during well operation, wherein the processing comprises:
• preprocessing a registered pressure wave and its reflections by applying a linear combination of a zero frequency notch filter and a lowpass filter, wherein application of the linear combination is configured to preserve a periodic structure of a reflected signal;
• transforming the registered pressure wave and its reflections from a time domain representation into a frequency domain representation with a Short Time Fourier Transform (STFT);
• applying a predictive deconvolution filter to the frequency domain representation after transforming the registered pressure wave and its reflections into the frequency domain representation to produce a normalized intensity of wellbore reflectivity, wherein applying the predictive deconvolution filter comprises:
• generating a normalized intensity of wellbore reflectivity response;
• and
• tuning one or more expected two-way travel time intervals to improve a sensitivity of the predictive deconvolution filter;
• identifying the reflected signal on a plot in coordinates of reflection time as a function of physical time and determining a respective reflection time for a respective signal reflected from the wellbore reflectors;
• and
• determining a depth of a respective wellbore reflector by multiplying the respective reflection time by a pressure wave speed.