Wellbore Integrity Inspection Collimator Design
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Solution Overview
Problem
Current methods for inspecting the integrity of hydrocarbon-producing wells, such as ultrasound and radiation-based techniques, face challenges in accurately detecting defects like annulus and cement de-bonding due to similar signatures from oil and cement, and limitations in traversing multiple layers, especially in high-pressure and high-temperature environments.
Innovation Solution
An apparatus and method utilizing a source collimator with alternating blocking and passing channels to direct radiation into a wellbore, allowing for multiple field of views and precise imaging of wellbore integrity, using high-energy radiation (X-ray or Gamma rays) to differentiate densities and detect defects like voids, cracks, and cement de-bonding with high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasound waves are used to detect defects, then the inspection can be performed in the wellbore, but the similar attenuation signatures of oil and cement make it difficult to accurately determine the presence and extent of defects
Solution Approach 1:
The patent replaces ultrasound-based mechanical wave detection with X-ray/Gamma-ray electromagnetic radiation detection. This substitution fundamentally changes the detection mechanism from acoustic wave reflection to radiation attenuation measurement, enabling clear differentiation between cement and hydrocarbon fluids based on their distinct radiation attenuation properties, thereby resolving the signature confusion problem
Solution Approach 2:
The patent changes the detection parameter from acoustic impedance (ultrasound) to radiation attenuation coefficient (X-ray/Gamma-ray). This parameter change allows for unambiguous identification of cement versus hydrocarbon because these materials have significantly different attenuation coefficients for electromagnetic radiation, eliminating the signature overlap problem
2Measurement precision
If a single radiation source and detector are used, then the device is simple, but it cannot provide multiple field of views to inspect all layers of the wellbore
Solution Approach 1:
The patent segments the radiation detection system into multiple source-detector pairs, each oriented at different angles to provide distinct field of views. This segmentation allows simultaneous inspection of different wellbore layers (casing, cement, formation) from multiple perspectives, enabling comprehensive multi-layer defect detection while maintaining manageable device complexity through modular configuration
Solution Approach 2:
The patent introduces angular dimension by arranging sources and detectors at different orientations around the wellbore. This dimensional change from single-point detection to multi-angular detection enables coverage of all wellbore layers without requiring complex mechanical scanning, as each source-detector pair captures information from a specific angular sector
3Measurement precision
If complex statistical signal processing is employed, then defect detection sensitivity may improve, but the inspection procedure becomes complex and time-consuming
Solution Approach 1:
The patent replaces complex statistical signal processing of ultrasound data with direct measurement and analysis of radiation attenuation. The substitution of detection physics enables simpler, more direct defect identification through attenuation ratio calculations, significantly reducing processing time while maintaining or improving detection sensitivity
Solution Approach 2:
The patent changes the analysis parameter from complex statistical features of reflected acoustic waves to straightforward radiation attenuation coefficients. This parameter change simplifies the data processing requirement from sophisticated statistical analysis to direct comparison of attenuation values, reducing inspection time while preserving defect detection capability
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 accurate detection and imaging of wellbore defects across multiple layers, improving precision and reliability, and simplifying the inspection process by eliminating the need for rotating parts, thus enhancing safety and reducing maintenance costs.
Implementation Method 1
utilizing a source collimator with alternating blocking and passing channels to direct radiation into a wellbore, allowing for multiple field of views and precise imaging of wellbore integrity, using high-energy radiation (X-ray or Gamma rays) to differentiate densities and detect defects
Implementation Method 2
A source collimator having a plurality of alternating blocking channels and passing channels to direct radiation to impinge the target volume, such that the radiation directed from each passing channel forms a plurality of field of views extending radially into the target volume
Implementation Method 3
at least one detector to receive backscatter rays arising from each respective field of view from the plurality of field of views and to generate an image representative of an inspected portion of the wellbore
Data Source
AI summary
An apparatus for inspecting integrity of a multi-barrier wellbore is described. The apparatus includes at least one source to generate radiation to impinge a target volume of the wellbore. The apparatus includes a source collimator having a plurality of alternating blocking channels and passing channels to direct radiation to impinge the target volume, such that the radiation directed from each passing channel forms a plurality of field of views extending radially into the target volume. The apparatus further includes at least one detector to receive backscatter rays arising from each respective field of view from the plurality of field of views and to generate an image representative of an inspected portion of the wellbore. The apparatus is useful for inspecting very small volumes in the multiple barriers of the wellbore and determine the integrity of the wellbore based on the different densities in the image of the inspected portion.