Liner wrinkling in offshore steel lined pipes during reeling installation

Abstract

A three-dimensional numerical model of a mechanically bonded lined pipe is developed, simulating its structural response during the reeling installation method. An installation/failure–repair scenario is considered with five winding–unwinding cycles, accounting for the straightening process. The cyclic deformation of a lined pipe is presented, monitoring ovalization, local curvature and liner detachment from the outer pipe during reeling. The influence of pipe contact with the reel, and the effects of back tension on the structural response of the lined pipe are examined. The results indicate a residual curvature of the pipeline at the end of unspooling. Applying different levels of back tension, the local curvature on the pipe decreases, affecting the detachment of the liner pipe from the outer pipe. Numerical results on imperfection sensitivity demonstrate the significant influence of geometric imperfections on liner buckling. Comparison of the present results with those from a pure bending model shows that a lower liner detachment rate is predicted by the present model. Furthermore, the reeling performance of thicker liners is examined, showing the gradual reduction of liner detachment with increasing wall thickness. Finally, the reeling process in the presence of moderate levels of internal pressure is simulated, verifying its beneficial effect on structural performance, preventing local buckling. © 2021