Research Of Electric Surface-Controlled Subsurface Safety Valve

Subsurface safety valve is an indispensable part of offshore oil and gas exploitation equipment,which plays an important role in the protection of offshore oil and gas exploitation.The research of the subsurface safety valve is just initiated and immature in our country.On the contrast,foreign scientific research institutions have been studying the field of offshore oil and gas exploitation for several years.The technical innovation is carried out on the product prototypes of all kinds of subsurface safety valves,and the development ideas of electric surface-controlled subsurface safety valves are put forward.This situation has greatly restricted the exploitation of offshore oil and gas resources in China.Therefore,it is of great significance for the development of oil and gas equipment to research and design the electric surfacecontrolled subsurface safety valve technology,which can be in line with the international advanced technology.(1)The overall scheme design of the electric control subsurface safety valve is carried out,including the overall structure design of the safety valve body and the control scheme design of the control system.The design idea of the safety valve body is mainly studied,the threedimensional model of the valve body is established,the internal parts are classified and explained according to the function,and the working principle of the electric control subsurface safety valve is described in detail.(2)The key parts of the electric control subsurface safety valve are designed,including the design of the return spring,the design of the magnetic coupling module and the design of the differential pressure self-balancing device.The parameters of the return spring are optimized by Hessian matrix method.By using the equivalent magnetic charge method,the mathematical expression between the axial magnetic force of the main and subordinate moving magnetic rings of the same axis and the parameters between the magnetic rings is derived,and the physical parameters of the magnetic rings are given.The magnetic force of the magnetic coupling device is simulated by the COMSOL physical field analysis software,and the maximum axial magnetic force is obtained.By analyzing the flow state of the fluid in the concentric annular gap,the relationship between the balance time of the differential pressure self-balancing device and the size parameters of the plunger is studied,and the size of the balance plunger is selected.(3)Based on the analysis and calculation of the force on the balance plunger and outer magnetic ring,the power system of the electric control subsurface safety valve is selected,and the advantages and disadvantages of the three kinds of lead screw nuts are compared.Finally,the planetary roller lead screw is selected as the motion conversion mechanism of the device.By analyzing the motion principle of the planetary roller lead screw,the parameters of the parts of the planetary roller lead screw are calculated according to the requirements of the motor output torque.Finally,the 3D model is drawn and imported into the kinematic simulation software for simulation.The simulation results verify the accuracy of the designed parameters.(4)The simulation of flow field and stress field of arc valve plate with different opening is established.The simulation results show that in the process of opening the valve plate,the low-speed vortex will form on its surface,and the position of the low-speed vortex will continuously shift to the center of the upper surface of the valve plate.The low-speed vortex will be conducive to the opening of the valve plate.With the increase of the opening angle of the valve plate,the position of the maximum stress of the fluid also transfers to the transition point of the upper and lower surface of the arc valve plate.According to the simulation results,the material strength of the transition point of the upper and lower surface of the arc valve plate can be increased properly when the valve plate is designed.Through the method of fluid structure coupling,the stress at the joint of valve plate and valve seat is analyzed,and the maximum stress is obtained.Experience proves that the maximum stress at the joint of pin shaft is always less than the yield limit of material,and the designed valve plate meets the requirements.