Offshore Workover Derrick Mechanics Analysis

On the base of collecting the information of the design, analysis, calculation and using of the ocean workover rig, this paper checked the intensity of the homemade HYX90 ocean workover derrick serving on the Qinhuang island 32-6 flat. We first applied the simulative wind loads on the derrick, analyzed the response and calculated the time response course of stress, displacement and velocity on the vary parts of the derrick when the ocean workover rig was in the simulative hurricane. This offered the theory basis and way for bettering the work capability, optimizing the ocean workover rig's structure and improving the research level. The work this paper discussed is the need of the oil field and the main work in the cooperate item "studying the wind tunnel test scheme of the ocean workover rig and optimizing structure". The main studying work is following:1 . Through collecting the information of the ocean workover rig, the specialty and disparity between inside and outside country were found. Combining the technology actuality of homemade ocean workover rig with the yield practice in oil field, the detailed study scheme was brought forward;2. The 3D model of the main part of the HYX90 ocean workover rig - derrick was drawn using Pro/E software. This provided the more mechanics analysis and optimization design of the ocean workover rig with model basis;3. There was no uniform criterion on the wind vibration coefficient of the derrick. The thesis calculated the wind vibration coefficient of the derrick according to the stochastic vibration theory considering the HYX90 ocean workover derrick's structure characteristic. This work offered the calculation of the wind loads applying on the derrick with theory basis;4. According to the specialty of the wind load, we simulated the wind loads on the HYX90 ocean workover derrick applying the fundament of simulating the stable normal stochastic process. The time process curve of the wind load acting on the derrick was drawn;5. On the basis of the finite element model of the HYX90 ocean workover derrick, the logical constraint and load condition were confirmed according to the workover condition. This work offered the correctness of the mechanics analysis with theory basis;6. The static mechanics analysis of the HYX90 ocean workover derrick was carried out in the Structure module of the Pro/Mechanica. We calculated the displacement and stress of the derrick in vary condition and found its danger part during working. These data supplied the optimizing design of the derrick with reference data;7. The mode analysis of the HYX90 ocean workover derrick was done and the anterior 8 modes and natural frequencies were calculated. The arouse frequency near the derrick's was found and avoided the sympathetic vibration because of the incorrect operation;8. We first applied the simulative wind loads on the derrick, analyzed the response and calculated the time response course of stress, displacement and velocity on the vary parts of the derrick when the ocean workover rig was in the simulative hurricane. This provided the estimating dynamical characteristic of the derrick with theory basis.This thesis checked the intensity of theHYX90 ocean workover derrick using Pro/Mechanica software. The danger part of the derrick was found during working. We compared the results with test data and validated the model's rationality and the result's correctness. On the basis of these works, we first applied the simulative wind loads on the ocean workover derrick, analyzed the vibration response in the time field. This redeemed the limitation that there has not been the wind-induced response analysis on the derrick all the time. The referenced data was offered to the betterment and design of the ocean workover derrick. And, the technique and results had theory directing meaning for the dynamics analysis of the derrick in the oil field.