Research On The Sealing Of Intelligent Downhole Flow Control Valve

The flow control valve is the core component of the intelligent well and is the actuator for intelligent mining to achieve intelligent mining.The flow control valve relies on the pressure signal to control the opening degree.In order to ensure that the pressure signal can be accurately transmitted to the flow control valve and perform the opening adjustment task under the pressure,the flow control valve needs to have a good seal.In the high temperature and high pressure environment under the well,the sealing system is more required to have higher sealing performance and longevity.This paper studies and analyzes the sealing problem of intelligent downhole flow control valve.The main contents include:The first chapter introduces the development and research status of seals at home and abroad,and explains the research background,research content and research significance of the thesis.Chapter 2:Analysis of the sealing characteristics of the flow control valve.The sealing environment of flow control valve,common sealing material and sealing material constitutive model are introduced.The sealing mechanism of static sealing and dynamic sealing in flow control valve is analyzed.The calculation formula of contact pressure of static sealing surface is obtained,and the leakage calculation of dynamic sealing is calculated.Formula and discuss and analyze the main failure modes and life of O-rings.Chapter 3:finite element simulation analysis of O-ring seal.The contact stress and internal stress of the sealing ring were obtained.The effects of compression ratio,radial compression ratio and fluid pressure on the sealing performance and life of the sealing ring were analyzed.The variation of contact stress,internal stress strain and shear stress of O-ring in reciprocating motion is analyzed.The main reason for the failure of O-ring in dynamic seal of downhole equipment is that the seal is subject to friction and wear and shear damage.Chapter 4:Analysis of the combined seal.The change of sealing performance of the VL combination seal during static sealing and dynamic sealing is analyzed,which shows that the L-shaped wear ring has a protective effect on the O-ring.The calculation and comparison of the leakage and friction of the VL combination seal and the O-ring seal and the Cheer seal indicate that the VL combination seal has better sealing performance,better adaptability and reliability in the downhole equipment.Chapter 5:Designed a non-metallic sealing experimental device for the non-metallic sealing structure of the flow controller.The experimental bench is mainly composed of three parts:pressure vessel,hydraulic control system and electronic control system.It can be used at 70MPa pressure and 150°.