Design And Analysis Of A Multi-cavity Hydraulic Workover Machine

The hydraulic workover rig has many advantages compared with the traditional workover rig.For example it has changed the operation mode of traditional workover rig that promoting pipes by the diesel engine cooperate with the travelling block,the hydraulic workover rig can greatly improve the efficiency of work,reduce the labor intensity of worker and alleviate the environmental pollution.This paper has designed a new type of multi-cavity hydraulic workover rig combine with the intership project based on the deepen understanding of the workover rig at home and abroad and deeping study of the hydraulic workover rig.The multi-cavity hydraulic workover rig means to use vertical differential hydraulic cylinder and moving pulley group to lift string,The multi-cavity mens to the new hydraulic cylinder has four cylinder,but the traditional hydraulic cylinder has only two cylinder.It can change the lifting speed according to the load by controlling the inlet and outlet of the four cylinder.This new structure can improve the efficiency of workover rig and reduce the labor intensity of workers.As the central part of multi-cavity hydraulic workover rig,this paper designed the lifting system of multi-cavity hydraulic workover rig.The design includes four aspects: mechanical structure design、hydraulic control system design and simulation、analysis of key parts and modal analysis.First of all,this paper analyzed and studied the development and application of various workover rigs,and organizd the related information and data,i understanded the structural characteristics and the control process of hydraulic workover rig through this process.this paper completed the whole structure scheme of the multi-cavity hydraulic workover rig,designed the structural of lifting system,drawn the 2d diagram of the lifting system by CAD software,drawn the 3d model of the lifting system by Solidworks,introduced the working principle of the lifting system in detail,analyzed the type of load in the work,and determined the parameters of the lifting system.Secondly,this paper designed the hydraulic control system of the lifting system of the multi-cavity hydraulic workover rig,the lifting system can realize the design requirements of adjusting the lifting speed according to the load,this paper also selected the hydraulic components of the hydraulic control system,simulated and verified the designed hydraulic control system by Amesim software,and got the curve of displacement-time and speed-time of piston rod,the curve provided the rationale for field test.Thirdly,this paper analyzed the key parts of the lifting system of the multi-cavity hydraulic workover rig under their extreme working conditions and maximum force by using the static analysis method,the key part inclouded the crown block、the pull rod and the hinge pin between the lifting cylinder and the luffing cylinder,and then observd the deformation and stress of each part,this paper also got the stability analysis of lifting cylinder.It provided the safety and reliability rationale of the parts of the lifting system.Finally,this paper introduced the modal analysis in brief,made a modal simulation of the lifting system of multi-cavity hydraulic workover rig by ANSYS,calculated the first ten natural frequencies of the lifting system.So we should avoid these frequency values and prevent resonance,it could guide the practical workover operation.