Multi-variable Cement Evaluation Workflow for Multiple Casing Strings
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Solution Overview
Problem
Current methods for evaluating cement bonding in wellbores rely on indirect measurements from sonic and ultrasonic tools, failing to accurately characterize cement integrity and annular flow paths, especially in multiple casing strings, which is critical for plug and abandonment operations and fluid isolation.
Innovation Solution
The use of sonic, ultrasonic, density, and neutron tools to provide direct and accurate measurements of cement bond quality and annular equivalent density, integrating data from these tools to characterize cement-casing interfaces without requiring new hardware or adaptations, allowing for the detection of defective cement bonds and fluid migration paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If indirect measurement methods using single sensor system are used, then device complexity is reduced, but measurement precision and reliability of cement bond evaluation deteriorate
Solution Approach 1:
The patent combines multiple independent sensor systems (sonic, ultrasonic, density, and neutron tools) into an integrated evaluation workflow. Each tool measures different physical properties of the cement annulus, and their data are merged through a unified inversion process to derive accurate cement parameters, thereby achieving high measurement precision without requiring a single complex sensor system
Solution Approach 2:
The patent creates a multi-functional evaluation system where a single workflow framework can process data from various types of sensors (sonic, ultrasonic, density, neutron) and perform multiple evaluation functions (cement parameter derivation, bond quality assessment, flow path detection). This universal approach improves measurement precision while avoiding the need for specialized complex hardware for each measurement type
2Ease of operation
If current single-interface evaluation methods are used, then ease of operation is maintained, but adaptability to multiple casing strings deteriorates
Solution Approach 1:
The patent segments the wellbore into multiple evaluation zones corresponding to different casing strings and interfaces. The workflow processes each interface (first casing-formation, second casing-first casing, third casing-second casing) separately through the same inversion algorithm, allowing systematic evaluation of multiple casings while maintaining the simplicity of a standardized operational procedure
Solution Approach 2:
The patent creates a dynamic evaluation framework that can adapt to different well configurations (single casing, double casing, triple casing) by adjusting the number of interfaces to evaluate. The same core workflow methodology remains operational across different scenarios, providing both ease of operation and adaptability to multiple casing strings
3Device complexity
If indirect inference methods are used, then device complexity is reduced, but reliability of fluid flow path identification deteriorates
Solution Approach 1:
The patent replaces indirect mechanical inference methods with direct physical measurement approaches. By using density tools to directly measure annular equivalent density and neutron tools to directly characterize annular media, the system achieves reliable fluid flow path identification through direct physical property measurement rather than indirect mechanical inference
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 evaluation and characterization of cement bonds, enabling more precise identification of gaps and defects, thereby preventing fluid migration and contamination, and allowing for targeted sealing to maintain well integrity.
Implementation Method 1
obtaining sonic data of the first and second annular media using a sonic wave emitted from a sonic data tool included in the tool string
Implementation Method 2
obtaining ultrasonic data of the first annular media using an ultrasonic wave emitted from an ultrasonic data tool included in the tool string
Implementation Method 3
obtaining density data of the first annular media using gamma rays emitted by a density tool included in the tool string
Implementation Method 4
obtaining cased-hole neutron data using a neutron porosity tool included in the tool string
Data Source
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AI summary
Sonic data, ultrasonic data, density data, cased-hole neutron data, and open-hole neutron data of the wellbore are obtained. The sonic and ultrasonic data provides the amplitude, frequency, and phase of the altered sonic and ultrasonic waves. The far counts, near counts, and energy spectrum are obtained from density data, cased-hole (CH) neutron data, and open-hole (OH) neutron data. The amplitude, frequency, and phase provide the interface densities of the first, second, and third interfaces. The hydrogen index (HI) of the formation and the cased wellbore are obtained from the CH and OH neutron data. The widths of the second and third interfaces are obtained from the HI's and the densities of the second and third interfaces.