ABSTRACT

During the installation process, drag anchors may impact or hook with subsea pipelines buried in seabed, resulting in damage to the pipelines. The inshore subsea pipeline is often protected by a rockfill protection layer, so the pull-out trajectory of drag anchors in the rockfill protection layer is the key index to evaluate the protection performance of rockfill protection layers. At present, there are few researches on the installation process of drag anchors in rockfill protective layers. In this paper, the installation process of drag anchors in the seabed was simulated based on Coupled Eulerian-Lagrangian Method (CEL), and the installation trajectory of drag anchors in the clay seabed was obtained. The embedding-pulling motion trajectory of drag anchors in a rockfill protective layer with different particle sizes was simulated by Discrete Element Method (DEM). The numerical simulation results can provide a reference for the risk assessment of subsea pipelines and the performance study of rockfill protection layers.

INTRODUCTION

Drag anchor is the most widely used mooring device. Under the pull of anchor chains, the drag anchor will drag a certain distance to ensure that it reaches the designed working depth. Subsea pipeline is an important part of offshore oil and gas engineering, which undertakes the important task of transporting materials between sea and land. In the process of drag anchor installation, if it impacts or hooks with subsea pipelines buried in the seabed, subsea pipelines may have damage accidents such as fracture and leakage, resulting in huge economic losses and environmental damage. In recent years, with the gradual improvement of navigation capacity and frequency at sea, the damage caused by anchor movement has become one of the main risks faced by subsea pipelines, and more and more attention has been paid to research on the installation trajectory of drag anchors in seabed.

This content is only available via PDF.
You can access this article if you purchase or spend a download.