Design And Research Of Hydraulic Rolling Casing Repair Device

Influenced by engineering factors,geological factors and corrosion factors,the casing eventually suffers from Necking Deformation,distortion,fracture and corrosion perforation.As the most common type of casing damage in domestic oilfields,deformation causes huge economic losses.Aiming at the problems of long construction time,poor controllability of repair process,high cost and low service life of tools existing in traditional repair technology of deformed casing,a new type of hydraulic rolling casing repair device is designed in this paper.The new type of repair device can use the hydraulic system to control the casing shaping process;When the string connection repair device is put into the well once,it can continuously repair the deformed casing,shorten the workover time and reduce the repair cost.The new type of hydraulic rolling casing repair device is composed of anchoring device,double spiral swing hydraulic cylinder group,direct acting hydraulic cylinder group,radial bending device and spherical convex shaping head.Using CAD,Solid Works and other design software to complete the repair device structure design,get the assembly drawing and parts drawing.The hydraulic control system based on computer control is designed.Based on the mechanical knowledge,the theoretical formula of the depth of the anchor claw embedded in the casing is deduced.The anchoring process of the anchor claw is analyzed by the finite element simulation.The anchoring force and moment produced by a single axial anchor claw and a rotating anchor claw are determined to be 13.872 k N and 0.684 k Nm respectively.The structure design of swing hydraulic cylinder is completed,and the structure parameters of two-stage spiral gear pair are determined.By using Lagrange equation and virtual work principle,and considering the friction between the parts of screw pair,the dynamic equation of two-stage screw pair is established.The dynamic equation is analyzed by MATLAB,and the influence of helix angle and friction coefficient on output torque and mechanical efficiency is analyzed.The simulation analysis is carried out by using Adamas to determine the curves of the angular displacement of the transmission shaft and the displacement of the mass center of the hollow piston with the simulation time,and the curves of the output torque with the driving force.The calculation formula of repairing force produced by direct acting hydraulic cylinder group is deduced.On the basis of previous theoretical analysis,the process of spherical convex shaping head repairing deformed casing is further analyzed,and the theoretical formulas of repair force and repair torque are derived.The repair process is simulated by ANSYS.Based on the analysis of the influence of the structure parameters of the shaping head on the repair process of the elliptical deformed casing,the optimal structure size parameters are selected: the curvature radius of the spherical bulge is 11 mm,the axial length of the shaping head is 150 mm,nine rows of bulges are arranged,and the number of circumferential bulges is 22.The influence of casing damage type,confining pressure,friction coefficient and repair amount on casing repair process is analyzed.The new repair device is suitable for casing damage type: single point depression and elliptical deformation;The linear equations of confining pressure,friction coefficient,repair amount,maximum repair force and maximum repair moment are fitted respectively,which can provide reference for casing repair construction.Finally,the optimized shaping head is used to repair the elliptical deformation casing,and it is found that the rolling expansion is helpful to reduce the repair force compared with the direct expansion.