Research On The Righting Manipulator Buffer Mechanism For Catching Pipe In Large Automatic Workover Process

Currently,most domestic oilfields' workover operations still use workers and semi-automatic device together to achieve workover construction,which makes workover construction long-periodic,labor-intensive,and prone to accidents.Based on this situation,this thesis fully investigated current situation of domestic and oversea automatic workover devices and studied the operational relationship between various portions of the whole system.Then the results revealed that for the fixed catwalk workover system,the righting manipulator worked intensely and bore large impact.Based on the current existing equipment and to maximize the use of resources as far as possible,this thesis proposed and designed a buffer mechanism for righting manipulator catching pipe process,which is called righting manipulator buffer mechanism or receiver buffer mechanism later in the thesis,to assist the righting manipulator and improve the existing automatic workover devices.Therefore the traditional workover operation can be transformed into automatic conveniently.The main research contents are as follows:Firstly,this thesis summarized the research on righting manipulators of workover operations and various buffer devices in the domestic and overseas.Then analyzed the relationship between the righting manipulator and other parts of the automatic workover rig and discussed the key points for the righting manipulator buffer mechanism.Secondly,through the analysis of the righting manipulator movement in the workover down pipes process,the workflow of the righting manipulator buffer mechanism was confirmed and the overall design of the mechanism came up.Then the overall structure of the mechanism was determined,the hydraulic system was designed and the strength of key components was checked.Thirdly,the multi-body dynamics theory was used to establish the kinematics and dynamics model for the righting manipulator buffer mechanism lifting process,then the corresponding displacement,velocity,acceleration equations and the hydraulic cylinders driving force equation of the mechanism in the arm lifting process were gained.Fourthly,the virtual prototype model of the righting manipulator buffer mechanism lifting process was established in the ADAMS software,also kinematics and dynamics simulation analyses were processed.Then the driving force curves of the hydraulic cylinder and velocity,acceleration curves of the arm were obtained.Also it analyzed the impact force between the pipe and receiving part.Compared with different materials and shapes of the receiving part and different arm swing angles,different impact force curves were gained.So the material and shape of the receiving part and arm swing angle of the mechanism were chose from it to decrease the impact force.Lastly,inside hydraulic cylinder throttle buffer device was used in the righting manipulator buffer mechanism.The mathematical models of fixed throttle and variable throttle buffer devices were established in the MATLAB and Simulink software to do modeling and simulation.Then the buffer characteristic curves of two different buffer devices were gained.Compared with the simulation results,the thesis summarized that the mechanism used variable throttle buffer device,arranging the orifices reasonably at the end of the buffer chamber,could get better buffering effect.In this thesis the righting manipulator buffer mechanism could meet the demand of practical engineering,and it could also improve the workover automation system.And the results had some reference value to relevant research.