On bottom Stability of Pipelines against Wave and Current Forces; Case Study at Northern Parts of Kish Island

Offshore pipelines are usually used for transferring oil or gas productions from a source point to a terminal destination. On-bottom stability analysis of offshore pipelines is a challenging task. Hydrodynamic pressures act as active forces and pipe weight acts as the main resistive force. Therefore, it is so important to evaluate the hydrodynamic forces accurately. Hydrodynamic forces along a pipeline located between Kish Island and the main land of Iran is evaluated in this study. For this purpose, wave parameters and current velocities are modeled by means of a calibrated Mike۲۱ model and then, Morison equations have been utilized to predict the applied forces on the pipe route. The importance of current forces in comparison to the wave forces is analyzed and it is concluded that the wave force is dominant to the current force even in a sheltered area such as Kish Island. However, it is also necessary to consider current forces even inside the surf zone. According to the results, the maximum load along the pipeline occurs near the outer boundary of the wave-breaking zone and a smaller local peak load occurs inside the surfzone.

Keywords:

Pipeline , hydrodynamic forces , wave , current , stability