Research Of Subsurface Safety Valve System For Subsea Production System

Subsea safety valve system is indispensable part of subsea production system,because its reliability and fail-safe feature are directly relate to the safe of production process,and it is the barrier of well integrity.The research of the subsea safety valve system is just initiated and immature.On the contrast,the foreign institute has ran the subsea production system for several years and conducted lots of research of subsea safety valve.This situation restricts the exploitation of the offshore hydrocarbon resource of China.So the domestic design and research of subsea safety valve system is very significant for China.In this thesis an innovative subsea safety valve system is designed after fully investigating the related technologies.The major unique parts of the design are driving force system and buffering structure.In driving force system,there are two pistons offering thrust and pull,so the spring is no need.And fail-safe structure is fused in driving force system to ensure the safety when subsea safety valve system is out of control.To avoid flapper crash and hydraulic shock,the buffering structure is devised.It can make the motion of flapper slower down at the final stage of the closing process.There are other structure designed to ensure the safety valve run well such as pressure equation valve and orbicular seal.The electro-hydraulic control system is also devised as a part of the system.The structure and dynamics of the subsea safety valve system is estimated when finished the design.Finite element method is used for analysis of structural strength and sealing performance to testify the reliability of the valve.Mathematical models are established to analyze the buffering structure.The dynamic properties of buffering process are verified via the models.Finally the hydraulic part of the control system is simulated to study the dynamics of the system.And the results show that the control system works well to ensure safety of well.The thesis offers some new ideas and theoretical foundation in design and analysis of subsea safety valve system,so it is valuable for research of subsea safety valve system...