The Basic Design And Analysis Of Deepwater J-Lay System

Because of the innate adaptability of deep water,J-Lay method has been widely used for pipe laying in deepwater.To better integrate into international deepwater engineering operation market,our country is planning to build a deepwater semi-submersible lifting and pipe laying vessel,with maximum lifting capacity of 16000 tons,equipped with a set of J-Lay system.The paper takes this vessel as target to develop the basic design and analysis of deepwater J-Lay system,the specific content as follows:On the basis of the research for J-Lay process and the international existing deepwater semi-submersible lifting and pipe laying platform's pipe laying proposal and performance parameters,in the comprehensive consideration of the J-Lay system's laying cost,efficiency and operability,carry out the selection analysis for J-Lay system,and design a new type of deepwater heavy J-Lay system aiming at the selection result,the system mainly including J-Lay tower,J-Lay tower angle adjustment system,J-Lay pipeline transport system,J-Lay critical equipment.After completing basic design,carry out the normal J-Lay cycle research on the designed system,verifying the rationality of system design;Develop the structure strength analysis for the infrastructure J-Lay tower of designed J-Lay system,elaborate the overall strength analysis method of tower,and establish the structural model of J-Lay tower by using finite element software,the content of analysis including the overall strength of the tower under the working conditions that target platform is in fully loaded voyage,standby self-existence,once-in-a-century self-existence,full loaded laying,crane vertical lifting.Check the structure strength of J-Lay tower's shell element and beam element in all working conditions and analyze the checking results;Carry out the construction technology research on J-Lay aiming at designed deepwater heavy J-Lay system,put forward the pipe laying program which is fit for the designed J-Lay system in the paper and focus on the technological process of pipeline initiation,pipeline termination which also includes the research on steel catenary riser taken as the preferred riser system in deepwater oil and gas resources development;Taking the steel catenary riser(SCR)as research object,carry out J-Lay research on riser.First develop J-Lay strength analysis for the pipe laying,pipe lifting,pipe transfer three installation steps of riser.Then,carry out the operation window analysis of the period that the force value acting on riser is maximum in pipe laying process,getting the environment parameters which meet the riser use condition.