Full Coupling Analysis Of Submarine Pipeline Laying

The demand and contend for energy is still growing in modern society.Oil and natural gas will play an important role for a long time.After years of onshore oil exploitation,people have gradually turned their attention to offshore oil resources.The submarine pipeline takes the advantages of high efficiency,low risk and low cost in the transportation of marine energy.However,the marine environment is so complex and changeable that the coupling effects influence the submarine pipe laying,especially for the deep-sea pipe laying.Therefore,it is of great theoretical significance and practical guidance to carry out full coupling dynamic analysis for submarine pipe laying.The study on the pipe response during S-lay and J-lay is performed.Considering the dynamic positioning of the ship,the integral finite element model of the hull-pipe-stinger or J-tower is established.The pipelaying coupling dynamic response is analyzed.The contents of the research include:1.The Study on the dynamic positioning(DP)control of pipelaying barge is carried out.The calculation method of PID control algorithm,and the theory of the distribution of the propeller thrust are introduced.The hull RAO and the propeller thrust under the DP control are discussed.Meanwhile,the hull displacements of pipelaying barge with and without the DP control are compared.2.Moses software is used to establish the S-lay and J-lay hull-pipe-stinger or J tower full coupled FE model.The three dimensional potential flow theory and Morison equation are used to calculate hydrodynamic loads applied to the hull and pipe,respectively.The full-coupled dynamic response of S-lay and J-lay pipeline is performed.The pipeline configuration and distribution of internal force are calculated.The factors affecting the submarine pipeline laying such as the water depth,pipe geometry,tensioner force,the radius of stinger,wave height,current velocity and environmental loads direction are discussed.3.The pipe stress at TDP,tensioner force and laying precision of S-lay and J-lay with water depths of 500 m,1000m,1500 m and 2000 m are computed.It is concluded that the S-lay is suitable for shallow water,while the J-lay for deep water.