Abstract:

Drilling riser is a critical component in offshore oil & gas industry. Due to the complicated alternating stress and corrosive environment, stress corrosion cracking (SCC) is the common defect on drilling riser in service. A novel chain alternating current field measurement (ACFM) probe array is proposed to detect surface cracks on drilling riser. The finite element method (FEM) is presented for analyzing the characteristic signal of surface crack. The space between the U-shaped excitation yoke and detecting sensor is determined by simulation. Based on the results of simulation, the chain ACFM probe with giant magneto resistance (GMR) sensor array system is set up and the drilling riser surface crack detection experiment is carried out. The results show that the maximum spacing of U-shaped excitation yoke and sensor array is 80 mm and 10 mm respectively. Furthermore, the chain ACFM probe with GMR sensor array system can detect and locate the surface cracks on drilling riser rapidly and quantitatively with a single pass scanning.

Key words: chain, drilling riser, GMR, SCC, ACFM