Response Characteristic Analysis For Self-balancing Subsurface Safety Valve

At present,when oil and gas are being exploited,they are basically carried out under relatively high working pressure environment.Not only the requirements for relative technical means of oil and gas harvesting have been gradually improved,but also the safety of oil and gas harvesting and environmental protection are also being strengthened.Subsurface safety valve as a safety device is more and more applied to land shallow oil and gas wells and offshore oil and gas wells.When there is an abnormal condition in the bottom of the well or the emergency of the ground platform,the subsurface safety valve can close the production channel through the related procedures and equipment to prevent the danger of the flow of the well into the wellhead.With the rapid development of deep well oil recovery,the installation depth of the subsurface safety valve in the underground is also gradually deepening,which makes the valve plate of the subsurface safety valve in the underground to overcome the great bottom hole pressure when it is turned on.Therefore,in order to cooperate with the top opening valve plate of the center pipe,the liquid control system needs to provide high pressure to the liquid control pipeline.The high pressure of the hydraulic control pipeline has seriously affected the service life and the reliability of the work.The successful application of self-balancing subsurface safety valve can solve this problem well,so it is of great significance to analyze the opening characteristics of the self-balancing subsurface safety valve.In this article,based on the research of the self-balancing side-hole subsurface safety valve and the valve plate piston self-balancing subsurface safety valve,the runner model of self-balancing side hole subsurface safety valve and the runner model of the valve plate piston self-balancing subsurface safety valve are established.The relation between the upper pressure of the valve plate and the opening time of the balancing valve is deduced when the bottom of the oil well pressure is constant.The balance time formula of the valve balance plate of the plunger balancing valve is obtained,and the influence of the installation depth of the subsurface safety valve and the size of the plunger balancing valve on the balancing time is analyzed.At the same time,the balance time formula of the side hole self-balancing valve is also obtained,and the factors that affect the balance time of the side hole balance valve are analyzed.Taking the side hole self-balancing subsurface safety valve as the research object,when the subsurface safety valve is opened,the vibration model of the system is established by force analysis,and the displacement response curve of the central pipe is obtained.A specific example is analyzed.When the center tube goes down for a certain time,it can make the central tube down time and the side hole balancing valve balance time consistent by changing the number of side hole balancing valves and the size of the slot,so that the opening of the subsurface safety valve is more successful and reliable.Through the establishment of flow channel model of subsurface safety valve with different opening angles,FLUENT fluid analysis software was used to analyze the distribution of flow field near the valve plate under different opening angles of safety valve.Combined with the post-processing tools of the fluid software,the forces acting on the upper and lower surfaces of the valve plate under different opening angles and the opening resistance of the valve plate under the action of the fluid are obtained.Finally,the unidirectional fluid-solid coupling analysis method is applied to the subsurface safety valve,and the stress distribution of the valve plate subjected to the fluid load under different opening angles is obtained.