| With the rapid development of China's economy,the demand for oil and gas resources is growing with each passing day.As the land reserve of oil and gas has been unable to meet the demand,China's oil and gas exploration and development has been shifted from the land and shallow water area to deep water area.Subsea production system is one of the core systems of deepwater development,of which the subsea tree is key equipment that can only be imported at present.In order to break the overseas technical monopoly,China has carried out researches on correlative technology in recent years and has developed prototype of subsea tree.Due to the complex structure and function,hazardous work environment and high installation and positioning requirements of subsea tree,the prototype needs to go through a series of tests so as to verify its function and performance,among which sea experiment is an important mean for testing the performance and installation technology of subsea equipment currently.So far,there are not sea experiment experiences of subsea tree domestically,neither are relevant standards.Meanwhile,few detailed technical literature about sea experiment exists at abroad.Therefore,further study should be conducted on sea experiment program,content,procedures and evaluation of subsea tree.Based on the sufficient investigation and analysis of the practical installation and testing experience of subsea equipment and in combination with the structure and function features of subsea vertical tree,researches on installation technology of subsea vertical tree are launched in this paper,including the selection of installation method,the installation sequence,the content of installation exercise,etc.At the same time,according to the purpose and the water depth of sea experiment,sea experiment program is formulated,main equipments are determined,sea experiment procedure is conformed,and the entire sea experiment operation process is finally refined.After that,according to the features of the marine environmental loads,the environmental load under the sea experiment circumstance is calculated by the unguided installation mechanical analysis,and through the force analysis in the process of guided installation of tree,mechanical model of cable-guide installation was established.MATLAB software is utilized to solve the mechanical model,and the changing rule of the lateral displacement that changes with the down-pass depth during the process of tree guide installation is obtained,so is the force feature of the cable.Meanwhile,OrcaFlex software simulation research is carried out,of which the theoretical results and simulation results are highly consistent.According to the calculation principle of the operating window,the combined conditions of different current velocity and wave height are calculated and the operating window of the tree and the tubing hanger is obtained.Finally,according to the sea experiment content and features of subsea vertical tree,the analysis and evaluation system of sea experiment of subsea vertical tree is established,evaluation indicators are determined through document study and Delphi method and every indicator weight is calculated by using Analytical Hierarchy Process.Expert Decision is simulated and fuzzy comprehensive evaluation method is adopted to evaluate the results of sea experiment.The research results of this subject provide theoretical and technical support for the next step of practical sea experiment of subsea vertical tree and turn into the effective guarantee of the practical sea experiment exercise.At the same time,it can also provide reference for the sea experiment exercise of other subsea production equipment. |
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