Analysis Of Mechanical Properties And Optimization Design Of Composite Sliding Sleeve Fracturing Ball

Sliding sleeve fracturing ball is a tool for segmented seal in the process of oil and gas drilling,so as to realize the multi-stage segmental fracturing of oil and gas Wells.Fracturing ball should have good strength to ensure that failure does not occur when fracturing.When the fracturing stage of a fracturing ball is higher,the advantages of increasing the production of oil and gas wells,shortening the construction period,and reducing the production cost are more obvious.In order to meet the requirements of fracturing stages and design pressures,the development of high-strength fracturing balls is required.In this paper,firstly,from a theoretical perspective,based on the Hertz contact theory,the expressions of the maximum contact stress and the half contact width at the interface between the fracturing ball and the ball seat were established.According to the above derived semi-contact width expression and the corresponding geometric relationship,the cone angle of the ball seat was designed.Then,the finite element method was used to study the deformation and stress of the fracturing ball seal structure.The influence of the liquid pressure,friction coefficient and cone angle on the deformation of the fracturing ball and stress distribution at the contact surface was discussed.It was found that as the friction coefficient increases,the contact stress and the contact width decrease,and thus the sealing reliability decreases.However,the failure risk of the fracturing ball is also reduced.By comparing with a fracturing ball with a functionally graded material,it is found that when the surface of a ball is plated with a more rigid functionally graded material,the pressure capacity of the fracturing ball can be increased.Finally,based on the secondary development of ABAQUS,the failure process of the fracturing ball was simulated,and the characteristics and mechanism of the failure process were analyzed.