Three-Dimensional Ultrasonic Reverse-Time Migration Imaging of Submarine Pipeline Nondestructive Testing in Cylindrical Coordinates

Submarine pipelines are a safe and energy-efficient mode of gas transport. However, due to the complex manufacturing process harsh operating environment, submarine subject fatigue cracks under long-term cyclic loading. A comprehensive high-precision characterization strategy for can effectively prevent potential safety hazards have significant economic social repercussions. As matter fact, pipeline defects cannot be reliably detected with current traditional 2D methods. On other hand, in ultrasonic testing, cylindrical geometry increases complexity 3D wave field space significantly influences accuracy detection results. In this paper, we put forward novel method image testing that is suitable coordinates. order accurately simulate signal received from pipelines, generalize staggered-grid finite-difference Cartesian coordinates ones full space. Then, processing performed on ultrasound simulation records, reverse-time migration imaging achieved using cross-correlation conditions. The results obtained simulations real data show proposed provides high-quality taking into account multiple scattering conversion information at bottom defects.