Research And Design Of Safety Assessment And Testing System For Derrick Capacity Of Oil Drilling Rig

Oil derrick is the main component of drilling machinery and equipment,providing the operating height and space for lifting and lowering drilling and placing drill string.It is a large and complex tower mast-type metal steel structure.Therefore,the safety and stability of oil derrick structure directly affects the safety and smooth operation of the whole drilling operation.According to "the oil rig derrick carrying capacity for testing evaluation method(SY6326-2008,SY 6442-2000 and SY/T 6326-1997)" and "API Spec 4F drilling and workover derrick,base specification" standard,The JJ170/42-K oil derrick is analyzed theoretically,tested in situ and simulated by finite element method,the overall characteristics and bearing capacity of the derrick are evaluated by different methods from different aspects.In this thesis,three methods for theoretical evaluation of oil derrick are summarized,namely,modal parameter evaluation theory of residual bearing capacity of oil derrick,reliability analysis theory of oil derrick and bearing capacity strength evaluation theory of oil derrick structure.The structural characteristics of oil derrick can be analyzed and evaluated from three aspects: residual bearing capacity,reliability of oil derrick and bearing capacity strength of oil derrick structure.It is important to evaluate the stability of derrick in use.According to the national energy administration of the industry standard "SY6326-2012",combined with electronic technology,embedded technology,communication technology,computer technology,the design based on resistance strain gauge,PIC microcontroller and RS485 bus field detection system,and use the system completed the JJ170/42-K type oil derrick static load and dynamic load data of in-situ test.Oil derrick is evaluated by field data detection.The finite element model of JJ170/42-K oil derrick was built with the finite element software ANSYS,and material properties and constraints were added to the finite element model of the derrick based on the actual parameters of the derrick.The static finite element analysis of JJ170/42-K oil derrick model under hook load and three different wind load conditions was carried out by using the finite element software structural static analysis method.The size and distribution of deformation and stress of derrick structure under different working conditions are obtained,the analysis results show that each working condition meets the static strength requirements of the derrick.The stability calculation of JJ170/42-K oil derrick is carried out according to the stability calculation theory algorithm,and the results show that the overall stability of the derrick is good and there is no serious instability phenomenon.The finite element stability of JJ170/42-K oil derrick was calculated and analyzed by using the structural buckling analysismethod of finite element software,the minimum buckling coefficient of the derrick is calculated as 1.1789,and then the critical buckling load of the derrick was 1240.1kN,which larger than the maximum designed hook load of the derrick,so the derrick will not suffer from major deformation and instability.In order to determine the natural frequencies and modes of the oil derrick structure and master the vibration characteristics of the structure,the structural modal analysis method of finite element analysis software was used to conduct the modal analysis of j170/42-k oil derrick,and the first ten order natural vibration shapes and natural frequencies of the oil derrick were obtained.Analysis results show that the oil derrick is mainly compressive deformation,the basic mode of vibration is the first mode form,the top of the derrick produces local torsional vibration,corresponding to the natural frequency of 0.83 hz,belongs to large structure of low frequency vibration.Is proposed in this thesis based on the theory of strength and stability of oil derrick bearing capacity evaluation method,a new field testing system for bearing capacity of oil derrick is designed and complete the field test of the static and dynamic load of the derrick,finite element analysis software is used to the static analysis,stability analysis and modal analysis of oil derrick under different working conditions,it provides theoretical reference and experimental data for field use and safety evaluation of oil derrick.Finally,the structural characteristics of oil derrick are evaluated by combining the measured data and finite element analysis results.