Mechanics Analysis And Safety Evaluation Of The Snubbing Key Components

Snubbing operation has the advantages of high efficiency, environmental protection andother features, present in the oil field has been widely used. Bearing structure is one of keyparts of the equipment, a reasonable description of the stress state and safety assessment ofsnubbing operation is crucial.An annular blowout preventer is the guarantee of snubbingoperation carried out smoothly, prevent blowout accident key equipment, the sealing processmainly consists of a spherical rubber core, the spherical rubber core sealing performancedirectly affects the reliability of annular blowout preventer, between a spherical rubber coreand the oil pipe, a spherical rubber core and a blowout preventer shell with double contactcharacteristics, and rubber materials with large deformation, material nonlinear characteristic,visible spherical rubber core sealing properties of a certain degree of difficulty.According to the BYJ70/21snubbing equipment bearing structure design dimensions,considering its working state, set up two kinds of bearing structure of three-dimensional finiteelement model, the maximum lifting force (660kN) condition and the maximum pressure(430kN) under the condition of bearing structure on the mechanical analysis is carried out,obtained in different conditions stress distributions and dangerous section,by introducing thedesign and analysis of stress classification method, the dangerous section is linearized, getecah stress, membrane stress,+bending stress distribution, according to the JB4732-95standards on the linear stress result is evaluated, the results meet the following conditions:membrane stress strength SⅡ≤1.5Sm; an additional two stress intensitySⅣ≤3Sm. Evaluationresults show that the bearing structure meets the strength requirement.FH18-21annular blowout preventer as the research object, considering the doublenonlinear contact and the rubber material nonlinearity, Mooney-Rivililn model was used toestablish the spherical rubber core rubber oil seals of three-dimensional finite element model,and through the ANSYS Workbench software on spherical rubber sealing73mm tubingprocess numerical simulation.Get the rubber core in sealed tubing during motion and stress,strain distribution, the radial displacement is the main factor of seal, rubber and skeletoncombination is the stress concentrated,designing should focus on it, analyzes seal tubingduring sealing parts of contact pressure and its change rule distribution, obtained after thecompletion of the rubber seal is formed around the8cm pressure platform, is the main sourceof the sealing pressure. Provides a theoretical basis for the snubbing design through the device bearing structurestrength analysis and safety assessment;the results of rubber numerical simulation can beuesed to the design and use of the spherical rubber core.