Research on the 3D Reverse Time Migration Technique for Internal Defects Imaging and Sensor Settings of Pressure...

Area of Science:

• Non-destructive testing
• Ultrasonic imaging
• Geophysical exploration techniques

Background:

• Pressure pipelines are vital for transporting oil, gas, and chemicals but are prone to fatigue cracks under cyclic loading.
• Current 2D ultrasound imaging struggles to fully visualize internal pipeline defects and topography.
• Accurate pipeline defect characterization is crucial for mitigating safety risks and ensuring operational efficiency.

Purpose of the Study:

• To introduce a 3D ultrasonic Reverse Time Migration (RTM) imaging method for pressure pipelines.
• To enhance the visualization of internal defects and optimize sensor settings.
• To address limitations of current 2D ultrasound imaging for pipeline inspection.

Main Methods:

• Adapted Reverse Time Migration (RTM), a geophysical exploration technique, for ultrasonic non-destructive testing.
• Developed a 3D ultrasonic RTM imaging approach tailored for cylindrical pipeline coordinates with absorbing and double free boundaries.
• Simulated wave field extrapolation and analyzed imaging results from various sensor configurations.

Main Results:

• Achieved high-precision 3D imaging of internal pipeline defects by suppressing artifacts.
• Demonstrated an imaging range accuracy up to 97.85% in both simulations and field data.
• Optimized the observation system design for improved imaging and interpretation of pipeline defects.

Conclusions:

• The proposed 3D ultrasonic RTM method offers superior imaging of internal pipeline defects compared to traditional methods.
• This technique effectively accounts for complex wave phenomena like multiple scattering and mode conversions.
• The optimized sensor settings provide a foundation for practical application in real-world pipeline integrity assessments.