Study On Structural Design And Optimization Of Coiled Tubing Drum

At present, coiled tubing technology has been widely used, and it mainly involves every stage from drilling to production. It not only makes great progress in the traditional operations, but also develops rapidly in other new operations, such as fishing, logging, cementing, reaming, descaling, completing and drilling. The coiled tubing drilling technology has gradually become the mainstream direction of petroleum drilling technology development because it has characteristics of high efficiency, wide adaptability, low pollution and cost. Compared with the mature coiled tubing equipment abroad, domestic study on coiled tubing technology starts relatively late and thus needs further studies. Coiled tubing drum is the representative device of coiled tubing machine, and its structure, size and mechanical properties are important factors of coiled tubing machine. Because of its simple structure, study on the drum is often ignored. There are some phenomena which will lead to the failure of operation in practice, such as pipe body deformation, winding disorder, injection head turning and coiled tubing slipping; In addition, size of the drum is too big, which restricts the operation capacity of coiled tubing machine. Therefore, the study wants to achieve the lightweight design of the drum through the comprehensive study on the winding mechanical properties of coiled tubing on the drum, load calculation, structure design and optimization of the drum. The study is of great significance to the improvement of operating properties and work life of the coiled tubing machine.Firstly, the calculation method of the coiled tubing’s tension force can be found through the analysis of bending internal force and winding model of the coiled tubing on the drum; Then, the tension and the axial force in different winding layers are obtained on the basis of determinate relaxation angle.Secondly, through the analysis of the overall force of the drum when coiled tubing is winded, we know that in working process the drum mainly bear the radial and axial pressure, weight of coiled tubing, concentrated force and torque effect of outer tubing on the drum; And the above load is calculated according to the formula of the material mechanics, combination of EXCEL and MATLAB.Again, the basic structure of the coiled tubing drum is designed according to the basic operation principle, function and structure of the drum, which mainly includes structure design of drum’s core and baffle, and three-dimensional geometrical modeling of the drum is bulit by using three-dimensional modeling software-SOLIDWORKS.Finally, there are still space for further optimizaion of drum’s structure by using WORKBENCH to analyze the strength of the drum structure on the basis of its load calculation and model establishment. Therefore, the best design plan of optimizing drum’s structure can be determined by calculating structure strength of different wall thickness and that of surface opening; The effect of drum load and different working conditions on the strength of the drum is analyzed. Through the study on the affecting factors of drum strength, we can have a better understanding of the properties of the drum and lay a foundation for further studies on drum.Through the analysis of winding model of coiled tubing on the drum and load calculation on the basis of the structure design of drum model, the finite element analysis and optimization of the drum’s structure are carried out in the study. The main results are as follows:(1) Formula of calculating internal force of coiled tubing is obtained though analysis of winding model of coiled tubing on the drum and usage of mechanics of materials and mathematics integral method; And formula of calculating coiled tubing tension force is obtained by using single variable calculation method in EXCEL.(2) The main load and calculation method of the drum is found through the analysis of the overall force; And the calculation program of the radial and axial load of coiled tubing winding the drum is formed by using the formula of material mechanics and scientific calculation software-MATLAB.(3) The thesis analyzes the structure strength of designed drum model, and optimizes the structure size by changing thickness of drum and design of reduction hole, which minimizes the weight of drum. Thus, mass of drum reduces 446kg with the reduction rate of 16.25%.In conclusion, the thesis uses the method of numerical simulation to analyze strength and optimize design of the drum on the basis of pressure analysis, load calculation, and structure design. Finally the best plan of optimizing drum’s structure is found, and the author realizes the purpose of lightweight design and lays certain fundation for further study on drum’s structure.