Blue-Shift Resonance Logging for Cement Channels Behind Casing
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Solution Overview
Problem
Traditional acoustic tools struggle to evaluate cement bond integrity behind production tubing without removing the tubing, as they lack sufficient energy to insonify the casing and are challenged by non-resonant acoustic waves, making it difficult to assess cement properties.
Innovation Solution
The use of acoustic logging tools that emit acoustic signals through conduit strings, allowing for in situ measurements by distinguishing between resonance and non-resonance waves, and separating these signals to determine cement bonding conditions, including fully bonded, free pipe, or partially bonded sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional acoustic tools are used to evaluate cement bond integrity, then the cement bond can be evaluated, but the production tubing must be removed to allow direct signal reach through borehole fluid
Solution Approach 1:
The patent uses resonance mode acoustic waves as an intermediary mechanism to transmit signals through the production tubing and casing system. The resonance waves are excited by an acoustic source and propagate through the tubing-casing-formation system, allowing cement bond evaluation without direct contact or tubing removal. The resonance frequency and quality factor serve as mediators that carry information about cement bonding conditions.
Solution Approach 2:
The patent replaces the traditional mechanical approach of removing production tubing with an acoustic field-based method. Instead of physically accessing the casing through mechanical means (tubing removal), the system uses acoustic resonance waves to penetrate the tubing and casing walls, substituting mechanical intervention with non-intrusive acoustic sensing.
2Measurement precision
If acoustic devices are used to insonify the production tubing, then cement evaluation is possible, but the acoustic devices do not have enough energy to insonify the production tubing
Solution Approach 1:
The patent employs resonance mode acoustic waves that exploit the natural vibrational characteristics of the tubing-casing-formation system. By tuning the acoustic source frequency to match the resonant frequency of the system, the acoustic energy is amplified through resonance, enabling sufficient insonification of the production tubing and casing without requiring excessive input energy from the acoustic device.
Solution Approach 2:
The patent changes the frequency parameter of the acoustic signal to match the resonant frequency of the tubing-casing system. This parameter adjustment transforms the acoustic signal from a non-resonant low-energy state to a resonant high-energy state, dramatically increasing the signal's ability to penetrate the tubing and casing while maintaining energy efficiency.
3Measurement precision
If resonance mode acoustic waves are used to evaluate cement bonding, then valuable CBL information is obtained, but it is difficult to evaluate a CBL in the presence of non-resonant acoustic waves
Solution Approach 1:
The patent extracts and isolates the resonance mode acoustic wave components from the total acoustic signal. By using frequency-domain analysis and resonance-based filtering, the system separates the resonant signal components (which contain cement bond information) from non-resonant background waves, effectively extracting the useful information while eliminating interference.
Solution Approach 2:
The patent utilizes the distinctive vibrational characteristics of resonance mode waves to differentiate them from non-resonant waves. The resonance waves exhibit specific frequency patterns, quality factors, and decay characteristics that allow them to be identified and separated from background noise through spectral analysis and resonance-based signal processing techniques.
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
Enables continuous monitoring of cement bonding without removing production tubing, providing accurate assessments of cement integrity through resonance mode acoustic waves.
Implementation Method 1
acoustic waves may resonate within a well, defined as resonance mode acoustic waves. Resonance mode acoustic waves may provide valuable information in CBL evaluation. Resonance mode acoustic waves may be sensitive to cement bonding with the casing in the presence of tubing.
Data Source
AI summary
A method comprising selecting a cement sensitive mode based at least on the configuration of a conduit string, transmitting an acoustic signal into at least part of the conduit string, measuring a return signal from at least part of the conduit string, computing one or more modal resonance frequencies of a resonance mode from the return signal, and forming a modal frequency log of the resonance signal with at least the one or more modal resonance frequencies. In examples, a system comprising a transmitter configured to transmit an acoustic signal into at least part of a conduit string, a receiver configured to measuring a return signal from at least part of the conduit string.