Analysis And Control Of Dynamic Response Of Suspended Pipeline In Shallow Seas

Submerged pipelines are the lifeline of the offshore oil field, which connect the whole production system together. Most of the gathering and storage of oil, gas, water in Marine oil fields, is accomplished through a submarine pipeline.However, the marine environment of a submarine pipeline is very complex. Especially when the submarine pipeline appears hanging. The situation is directly caused by the wave vacancies arise and the role of ocean currents because of erosion, residual stress and other factors. It is likely that the risk of the operation of submarine pipeline will increase because of many uncertainties factors. Therefore, it is particularly important to analyze of dynamic response of the hanging suspended pipeline and the control of hanging. Taking riser and horizontal hanging pipes in shallow seas as the research objects, a finite element model of riser and horizontal hanging pipe has been built up by the software-ANSYS on the basis of Hydrodynamic theory, Fluid-solid coupling theory and Finite element theory. Based on the comprehensive analysis of dynamic response of suspended pipeline in shallow seas, a set of benthic riser clamps of high adaptability named filling riser clamp have been designed based on the destruction of riser of offshore platform in Chengdao sea area. The results show that the span length of the pipe cross plays the most important part in dynamic response: all the dynamic responses increase and the natural frequency reduces with the increasing length of the pipe cross. It makes the pipe cross occur vortex-induced resonance more easily. How to reduce the span length of the pipe cross effectively has become the key factor to control damages related to pipe cross in submarine pipelines. The filling clamps and control countermeasure of span pipes which are researched in the paper can solve vortex-induced resonance of the pipe cross.