Tubular Thickness Measurement Using Complex Group Delay
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Solution Overview
Problem
Current methods for characterizing tubulars in boreholes, such as casing thickness and bond condition evaluation, face challenges with accuracy due to noise interference and unreliable detection of resonant frequencies in acoustic signals.
Innovation Solution
The method involves using an acoustic transducer to emit and receive signals, processing the data to determine complex group delay functions, and characterizing the tubular using phase delay functions, which provide more accurate thickness and bond condition assessments by analyzing the imaginary and real components of the group delay waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional acoustic signal analysis methods are used to determine tubular thickness, then the measurement process is simple, but the measurement precision is poor due to noise interference and unreliable detection of resonant frequencies
Solution Approach 1:
The patent applies partial action by extracting only the imaginary component of the complex group delay function rather than analyzing the entire complex signal. This selective extraction of the imaginary part provides sufficient information for resonant frequency detection while reducing computational complexity and improving measurement precision by focusing on the most relevant signal component
Solution Approach 2:
The patent transforms the acoustic signal from the time domain to the frequency domain using Fourier transform, and then derives the complex group delay function. By changing the parameter representation from raw acoustic amplitude to phase derivative with respect to frequency, the method enables more reliable resonant frequency detection and improves thickness measurement accuracy
2Measurement precision
If complex signal processing methods are used to improve accuracy, then measurement precision improves, but the ease of operation deteriorates due to complex data transformation and analysis requirements
Solution Approach 1:
The patent extracts only the imaginary component of the complex group delay function for bond condition evaluation. This extraction principle simplifies the operational process by eliminating the need to process the entire complex signal, while still maintaining high measurement precision through focused analysis of the most informative signal component
Solution Approach 2:
The complex group delay function serves as an intermediary that bridges the raw acoustic signal and the final thickness/bond condition measurements. By introducing this intermediate transformation step, the patent enables more accurate measurements while keeping the final analysis straightforward through component extraction
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of tubular characterization by reliably determining resonant frequencies and bond conditions, overcoming limitations of prior art methods, and allowing for more precise maintenance and operation of boreholes.
Implementation Method 1
obtaining acoustic waveform data in a time domain using an acoustic transducer configured to emit an acoustic signal and receive a return acoustic signal
Implementation Method 2
emit an acoustic signal and receive a return acoustic signal
Implementation Method 3
transforming, by a processor, the acoustic waveform data into a frequency domain using a frequency domain transform
Implementation Method 4
determining, by a processor, a complex group delay function Gk derived from the frequency domain acoustic waveform data to provide a phase delay function as a function of frequency, wherein the complex group delay function Gk represents a first derivative of phase in the frequency domain with respect to frequency
Data Source
AI summary
A method for characterizing a tubular includes obtaining acoustic waveform data in a time domain using an acoustic transducer configured to emit an acoustic signal and receive a return acoustic signal and transforming the acoustic waveform data into a frequency domain to provide frequency domain acoustic waveform data. The method also includes determining a complex group delay function Gk derived from the frequency domain acoustic waveform data to provide a phase delay function as a function of frequency, wherein the complex group delay function Gk represents a first derivative of phase in the frequency domain with respect to frequency. The method further includes determining an imaginary component function of the complex group delay function Gk to provide a phase delay function as a function of frequency and characterizing the tubular using the phase delay function.