Wellbore Detector Assembly for Multi-Casing Defect Resolution
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Solution Overview
Problem
Current methods for monitoring the integrity of wellbores, particularly multi-barrier hydrocarbon producing wellbores, face challenges in detecting defects beyond the first metal casing/cement interface and offer poor resolution in defect detection, requiring the retrieval of long metal tubing for inspection.
Innovation Solution
A detector assembly with scintillators arranged in specific patterns, coupled with first and second detectors, and a scintillator collimator, is used to generate and receive backscatter signals, providing depth and azimuthal resolution, allowing for in-situ inspection of wellbore integrity beyond the first casing/cement interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current techniques are used to detect defects in multi-barrier wellbores, then defects may be detected, but the resolution of defect detection is poor
Solution Approach 1:
The detector assembly is divided into multiple scintillator elements arranged in specific patterns, with each element detecting backscatter signals from different spatial regions. This segmentation enables the system to resolve defects at multiple locations simultaneously with improved precision, directly addressing the contradiction between measurement precision and reliability in defect detection
Solution Approach 2:
The patent introduces azimuthal resolution as an additional dimensional parameter beyond traditional radial detection. By arranging scintillators in specific angular patterns and measuring backscatter signals from multiple azimuthal directions, the system achieves three-dimensional defect localization, significantly improving both the precision and reliability of defect detection in multi-barrier wellbores
2Measurement precision
If long metal tubing is retrieved for inspection, then defects in casings and cement annuli can be inspected, but the operation becomes complex and time-consuming
Solution Approach 1:
The patent replaces the mechanical retrieval and physical inspection system with a non-invasive radiation-based detection system. A radiation source emits signals through the wellbore structure, and detector assemblies measure backscatter signals to identify defects in casings and cement annuli while the tubing remains in place, eliminating the complexity of retrieval operations while maintaining inspection capability
Solution Approach 2:
The patent introduces radiation (neutrons or gamma rays) as an intermediary medium to probe the wellbore structure. The radiation penetrates through casings and cement annuli, interacting with defect regions to produce detectable backscatter signals, thereby enabling indirect inspection without physical contact or retrieval of the tubing
3Ease of operation
If detection is limited to the first metal casing/cement interface, then simpler techniques can be used, but defects beyond this interface cannot be detected
Solution Approach 1:
The detector assembly is designed with multiple scintillator elements and configurable detection modes that enable it to detect defects at multiple interfaces (first casing/cement, second casing/cement, and intermediate cement annuli) using the same fundamental detection mechanism. This multi-functional design maintains operational simplicity while extending detection coverage throughout the entire wellbore structure
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 efficient, non-invasive monitoring of wellbore integrity with improved resolution, facilitating the detection of defects and structural flaws across multiple casings and annuli, including beyond the first metal casing/cement interface, without the need to extract the production tubing.
Implementation Method 1
a plurality of scintillators configured to generate a light signal in response to an impinging backscatter signal from a volume in an object
Implementation Method 2
an impinging backscatter signal from a volume in an object
Data Source
AI summary
A detector assembly includes scintillators configured to generate a light signal in response to an impinging backscatter signal, where the scintillators are arranged in a first pattern, a plurality of first detectors, where each first detector is coupled to a scintillator and configured to receive a first portion of a light signal from that scintillator, and where the first detectors are arranged in a second pattern aligned with the first pattern, a plurality of second detectors, where each second detector is disposed adjacent a scintillator and configured to receive a second portion of the light signal from that scintillator, and where the plurality of second detectors is arranged in a third pattern, and a scintillator collimator including a plurality of openings and configured to selectively receive the backscatter signal, where the detector assembly is configured to provide depth resolution, azimuthal resolution, a defect type, a defect size, or combinations thereof.