Open/Close Characteristics of Liquid-Gas Control Valve in Wellhead Control Device

The liquid-gas control valve is used to control the start and stop of the power pump in the blowout preventer control system and stabilize the manifold pressure of the control system.Considering the phenomenon of large pressure fluctuation in manifold on site,numerical modeling was used to identify the open/close characteristics of liquid-gas control valve from three aspects(gas source pressure,oil pressure port area,and spring stiffness),and the test verification was conducted.The results show that the gas source pressure has a relatively small impact on the open/close characteristics of the liquid-gas control valve,the oil pressure port area has a linearly inverse relation with the open/close pressure difference,while the spring stiffness has a conic relation with the open/close pressure difference.It is verified that the spring stiffness should be designed between 94 and 97.3 N/mm,and the oil pressure port area of the liquid-gas control valve should be reasonably increased,in order to achieve stable and precise control.The conclusions provide a theoretical basis for improving the accuracy of liquid-gas control valve,thus ensuring the safety and reliability of the pipe system.