Mechanical Analysis Of JJ170/45-K Derrick And Study On Stability Optimization

At present,due to the massive exploitation of oil and gas resources in various countries,the shallow surface oil and gas resources can no longer meet the demand,so the application ratio of ultra-deep well drilling rigs in oil fields has begun to increase.Nevertheless for deeper oil extraction,there have to have a strong derrick as the foundation.Therefore,research on the performance level of the derrick has been elevated to the primary strategic position for a long time.It has an effect on many functions in drilling hoist systems and suspended travelling systems,such as drilling tools,discharge pipe,casing and related operations.In the field of drilling derrick research,the stability of the overall structure of the oil rig derrick has been the focus of this aspect.This article specifically analyzes the JJ170/45-K drilling rig derrick in conjunction with the ANSYS analysis platform.Based on the analysis of the plane and space steel frame structural model,according to its structure and stress,the derrick model is used to simplify the principle and various parameter expression to establish a mathematical simulation model of the derrick system by the beam44 platform.The static performance of the derrick under the conditions of maximum design hook load and hoisting load is analyzed,and the dangerous area of the loading derrick is found.Then,based on the theory of linear buckling analysis that its stability is calculated and discussed.According to the theory of single-degree-of-freedom vibration system,its modal conditions are analyzed,and on this basis,the natural frequency and vibrational mode of the derrick are determined.Next,the finite element method is used to study the stress mode to determine the first 6 of order natural vibration modes.The comparative analysis results show that the basic vibration mode is the first-order vibration mode.During operation,it is found that under certain load conditions,which its mainly produces compression deformation,and regional torsional vibration occurs at the same time.Finally,the natural frequency of this derrick structure is calculated to be 1.58 Hz,which is at a low level.Through this natural frequency,designer can guide to change the frequency of the turntable or hook that causes the derrick to vibrate,that avoiding resonance and protecting the safety of people and property.Finally,the main thigh variable cross section plus welded steel plate method was selected to optimize it,and the results before and after optimization were comparedand analyzed.The maximum stress of the optimized derrick dropped by about 40%,the corresponding load-bearing performance was significantly improved,and the overall strength was also increased to a certain extent.Subsequently,it was tested in the laboratory,and the results of the comparison and analysis found that the simulated value and the measured value had a high degree of coincidence,thus indicating that the bearing capacity of the derrick can meet the requirements.Then the misering construction can be guided on site under the design load conditions.The research results in this paper can provide support for the application and design of this type of oil rig derrick,and have certain reference value.