Time Domain Coupling Analysis Of Dynamic Positioning Of S-lay Vessel

With the oil and gas exploration and development to the deeper water, the submarinepipeline plays a very important role in the transportation of the oil and gas. And the pipelinetechnology is requested higher as result of the complexity of the deep water work. So, deepwater installation and laying technology also become one of the main obstacles of our countryto develop deepwater oil and gas field, therefore, it is very important step to grasps the deeplaying technology in the development of deepwater oil and gas field. Among the pipelinelaying technology, S-lay is one of the main methods and shows many advantages in thedeepwater pipeline laying technology.This article focuses on the deepwater S-lay barge, launching the coupling analysis on thepipeline laying installation under the condition of the dynamic positioning, enclosing thecontent about S-lay ship motion performance analysis, dynamic positioning performanceanalysis, the coupling analysis of the barge-stinger-pipeline, mechanical characteristics andregularity of the laying pipelines.The analysis of the motion performance of S-lay ship. In order to study the influence ofthe assembly of the stinger on ship motion performance, it conducts the analysis of thestinger’s assembly on the ship performance in shallow and deep water (500m and3000m),and discusses the differences of the near field and far field formula through calculating theship’s second order wave forces. A series of computation of hydrodynamic parameters isprovided for the time domain simulation.The analysis of the dynamic positioning performance of the s-lay vessel. It compilesdynamic link library to package control function making use of the PID (proportion, integraland differential) dynamic positioning system theory, so it can realize the real-time control ofthe s-lay barge. In order to study the vessel’s dynamic positioning performance of thepipelaying operations, only considering the frequency motion of the ship, the paper analyzesship motion curves and thrust curves in the different flow direction, to verify the effectivenessof calling dynamic link library with dynamic positioning control function to realize real-timecontrol of s-lay vessel.The time domain coupling simulation in the pipe-laying operation. In the laying operation, the ship-stinger-laying pipe can be thought as a complicated dynamic mooringsystem. In order to simulate laying condition better, it firstly discusses the influence of thestinger form on the stress and strain in the pipelines installation, makes use of the continuousstinger model to conduct the stinger parameters optimization in four depths (145m and1175m,2000m and3000m). Then, it creates laying barge-discrete stinger-laying pipelinesystem model in four depths to realize the coupling analysis of the laying operations under thedynamic positioning. It is proved the coupling analysis’ accuracy and authenticity.bycomparing the coupling and uncoupling method in simulating the pipe-laying operation.Finally it discusses and summarizes the mechanical characteristics and variation law of thes-lay pipeline in the whole laying process.