Pulsed Eddy Current Casing Defect Detection
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Solution Overview
Problem
Current methods for wellbore casing evaluation, such as casing removal, are expensive and time-consuming, especially in offshore platforms, and do not effectively detect defects like corrosion, hindering efficient wellbore operations and production.
Innovation Solution
The use of pulsed eddy current techniques with time-domain evaluation methods that approximate the size and shape of defects by comparing response signals with a priori-known small defect information, allowing for better resolution and visibility of flaws in wellbore casings, even in larger diameters, using a Born approximation and multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If casing removal is used for evaluation, then defect detection capability is improved, but cost and time consumption increase significantly
Solution Approach 1:
The patent replaces the mechanical process of casing removal with electromagnetic eddy current testing. The system uses electromagnetic coils to generate eddy currents in the casing wall, and measures the resulting voltage signals to detect defects non-destructively, eliminating the need for physical removal while maintaining defect detection capability
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary between the inspection tool and the casing. The eddy current technique uses electromagnetic induction to probe the casing condition indirectly through electrical measurements, allowing defect detection without direct mechanical intervention or casing removal
2Measurement precision
If casing removal is used for evaluation, then defect detection capability is improved, but operational cost increases
Solution Approach 1:
The patent replaces expensive mechanical casing removal operations with electromagnetic testing that can be performed in-place. This substitution eliminates the high costs associated with rig mobilization, casing handling equipment, and disposal operations while maintaining the ability to detect defects
Solution Approach 2:
The patent enables the casing to be tested while remaining in its installed position, allowing the wellbore infrastructure to serve itself for inspection purposes. The existing casing structure is used as the test specimen without requiring removal, rehandling, or specialized processing facilities
3Speed
If traditional EC techniques are used, then inspection speed is improved, but defect resolution and visibility deteriorate
Solution Approach 1:
The patent uses pulsed electromagnetic excitation instead of continuous excitation. By applying periodic pulses and analyzing the transient response, the system achieves both rapid inspection speed and enhanced defect resolution. The time-domain analysis of pulsed responses provides superior defect characterization compared to traditional frequency-domain methods
Solution Approach 2:
The patent transitions from frequency-domain analysis to time-domain analysis of eddy current responses. By examining the temporal evolution of the voltage signal after pulsed excitation, the system extracts additional defect information that improves resolution and visibility while maintaining inspection speed
4Adaptability or versatility
If larger diameter casings are inspected, then applicability range is improved, but measurement precision deteriorates
Solution Approach 1:
The patent employs dynamic pulsed excitation and time-domain analysis that adapts to different casing geometries. The transient response characteristics provide scaling relationships that allow accurate defect detection across a wide range of casing diameters, from small to large, maintaining measurement precision regardless of the inspected structure's size
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 enables more precise evaluation of wellbore casing defects, improving operational efficiency and production by providing better resolution and monitoring capabilities for multiple casings, including those with larger outer diameters, and reducing the need for costly and time-consuming removal processes.
Implementation Method 1
Casing evaluation tools may include one or more electromagnetic coils configured to generate and direct pulsed eddy current excitation signals toward one or more defects in one or more casings in a wellbore and receive one or more response signals to the pulsed eddy current excitation signals
Implementation Method 2
one or more electromagnetic coils configured to generate and direct pulsed eddy current excitation signals toward one or more defects in one or more casings in a wellbore
Data Source
AI summary
A system comprises one or more electromagnetic coils configured to generate and direct excitation signals toward a plurality of casings in a wellbore and receive response signals based on the excitation signals. The system further comprises one or more processors configured to receive a first response signal from the one or more electromagnetic coils and determine one or more characteristics of a first defect in the plurality of casings using the first response signal and small defect information.