Well Integrity Inspection Using Neutron and X-ray Backscatter
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Solution Overview
Problem
Current technologies are unable to effectively inspect the integrity of multiple well casings and cement annuli at intermediate-to-surface depths in gas wells, particularly in areas with multiple stacked casing/cement rings, due to limitations in existing acoustic, electromagnetic, and ultrasound-based inspection methods.
Innovation Solution
A well integrity inspection system utilizing a combination of neutron and X-ray excitation and detection assemblies to transmit and receive backscatter radiation, allowing for the determination of well integrity parameters across multiple concentric layers, including the use of dual-mode imaging techniques that fuse data from X-ray and neutron backscatter with other inspection modalities like pulsed eddy currents and magnetic flux generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic imaging technology (CBL/VDL) is used to evaluate casing integrity, then single-walled structure inspection is possible, but multiple annuli inspection capability is lost
Solution Approach 1:
The inspection system segments the wellbore into multiple inspection zones corresponding to different casing annuli. Each zone is inspected independently using depth-coded acoustic signals, allowing the system to evaluate integrity of individual casings and cement bonds separately while maintaining overall system capability to inspect multiple concentric layers
Solution Approach 2:
The system transitions from traditional single-plane acoustic imaging to multi-dimensional inspection by incorporating depth coding and multiple reception zones. This enables simultaneous inspection of multiple annuli at different radial distances from the wellbore center, adding the dimension of radial depth discrimination to the inspection capability
2Measurement precision
If ultrasound-based techniques are used in gas filled wellbores, then drilling mud couplant is required, but operational complexity increases
Solution Approach 1:
The system extracts the requirement for drilling mud couplant by using acoustic signals that can propagate through gas-filled environments. By removing the need for liquid couplant, the system eliminates the operational complexity of mud circulation while maintaining inspection capability through alternative acoustic coupling mechanisms
Solution Approach 2:
The system replaces the mechanical/acoustic coupling mechanism that requires drilling mud with an electromagnetic or optical coupling approach. This substitution allows ultrasound-based inspection to function in gas-filled wellbores without the operational burden of maintaining liquid couplant circulation
3Measurement precision
If MFL inspection tools are used, then metallic structure damage detection is possible, but only innermost wellbore pipe inspection is limited
Solution Approach 1:
The inspection system segments the wellbore structure into multiple target zones (innermost casing, intermediate casings, outer casings) and applies MFL inspection to each segment independently. By depth-coding the acoustic signals and using multiple reception zones, the system can isolate and inspect each metallic structure at different radial distances, overcoming the limitation of single-pipe inspection
4Measurement precision
If eddy current sensors are used for crack detection, then metallic component inspection is possible, but spatial resolution decreases due to magnetic permeability variations
Solution Approach 1:
The system replaces eddy current sensors with acoustic-based inspection mechanisms. By using acoustic waves instead of electromagnetic eddy currents, the system eliminates the sensitivity to magnetic permeability variations that degrades spatial resolution. The acoustic signals provide consistent interaction with the structure regardless of magnetic properties, maintaining high spatial resolution for crack detection
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 more accurate and comprehensive inspection of well structures, providing earlier detection of defects such as cracks, corrosion, and disbonding, thereby enhancing operational safety and environmental protection by improving zonal isolation during drilling.
Implementation Method 1
a neutron excitation assembly and an X-ray excitation assembly configured to transmit radiation into the well structure
Implementation Method 2
a neutron excitation assembly and an X-ray excitation assembly configured to transmit radiation into the well structure
Implementation Method 3
a plurality of detection assemblies configured to receive a plurality of backscatter radiation returns from the well structure. The plurality of detection assemblies includes at least a neutron detection assembly
Implementation Method 4
The plurality of detection assemblies includes at least a neutron detection assembly and an X-ray detection assembly
Data Source
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AI summary
A well integrity inspection system (100) configured to inspect a well structure (102) including multiple concentric layers. The well integrity inspection system (100) includes an inspection probe (104) positioned in the well structure (102). The inspection probe (104) includes a plurality of excitation assemblies (132, 162) for transmitting a plurality of radiation emissions (134, 164) into the well structure (102). The plurality of excitation assemblies (132, 162) includes at least a neutron excitation assembly (132) and an X-ray excitation assembly (162). The inspection probe (104) also includes a plurality of detection assemblies (136, 166) configured to receive a plurality of backscatter radiation returns (138, 168) from the well structure. The plurality of detection assemblies (136, 166) includes at least a neutron detection assembly (136) and an X-ray detection assembly (166). The well integrity inspection system (100) further including a processor (190) operatively coupled to the inspection probe (104). The processor (190) is configured to determine a well integrity parameter of the well structure (102) based on at least one of the plurality of backscatter radiation returns (138, 168).