The Design And Research Of Subsea Valve For Oil Production

Subsea valve is an important part of the subsea production system,and it’s an important subsea mining equipment.The safe and reliable operation of the subsea valve is directly related to the safety of the subsea production system and even the entire oil field.The research of subsea valve is relatively backward,which restricts the development of marine natural gas industry in China.Therefore,it is of great practical significance to design and study the valve for subsea oil production and improve the reliability of its action.In combination with the present situation of subsea valve research at home and abroad,a subsea gate valve used at the water depth of 3000 m is designed in this paper,including valve body,gate,bonnet and valve seat.At the same time,the design of the actuator of the subsea gate valve is also carried out.Because the subsea gate valve works underwater,so we put forward higher requirements for the reliability of its operation.In view of the goal of improving the reliability of gate valve’s operation,the improvement of mechanical structure is made in this paper.On the basis of the existing mainstream hydraulic actuator,joined a set of independent operation of the screw drive actuator as a backup.When the hydraulic actuator failure,through the program control,the switching mechanism immediately action,then switching to the screw drive actuator for control the opening and closing of the gate valve.Seal design is another important part of the design of subsea gate valve.The seal of the gate valve designed in this paper,including seal of valve seat and gate,seal of valve cap,seal of balance lever,seal of piston,seal of the end closing ring and seal of actuator end.And several key seals were analyzed to verify the sealing performance.Return spring is an important part of hydraulic actuator.By the finite element analysis of seal to extract the contact pressure of the sealing surface,then the integral calculation is carried out on each unit,so as to get the seal friction force,and to provide data for the design of the return spring.In this paper,the return spring is made of parallel double spring,using MATLAB to carry on the optimal design of the return spring,then got the optimized program of the return spring.In addition,the valve control system is designed and studied in this paper.Using SETP 7 to develop the control program,and using SIEMENS PLC as the lower computer to achieve the control of the valve opening and closing action.And when hydraulic actuator failure,the control program starts the screw drive actuator immediately and continue to complete the valve opening and closing movement.