Research On Buckling Behaviors Of Coiled Tubing In Down Hole

Coiled tubing technology is the call of times with the developing of oil fields around the world,because of its high efficiency,safety,low cost,convenient transportation and operation.Coiled tubing is known as “Universal Machine”,and good at deepening old wells and sidetracking operations,this new technology has unlimited development prospects in oil and gas explorations.However,coiled tubing has initial residual plastic bending deformation,as a result of going through reel,gooseneck and injection head,at least 6 times bending deformation at each operation,the plastic deformation will lead to initial defect of coiled tubing,and make it easier to buckling and other failure behaviors.In this paper,the most important is the influence of buckling behavior in down well from initial residual bending of coiled tubing.The paper build finite element model with ABAQUS software,only focus on once operation and ignore plasticity accumulation.Main research contents are:(1)Firstly,simulate the process of going through reel,gooseneck and injector head,and calculate curvature of coiled tubing,then analysis the influence of coiled tubing diameter,reel radius,gooseneck radius and the length of injector head at curvature of coiled tubing.(2)Secondly,simulate moment-curvature finite element model,and get the curvilinear relationship and equation.(3)Simulate the process subjected to bending moment,and get moment-configuration.(4)In the end,simulate coiled tubing buckling process in down hole,analyze the influence of buckling behavior from diameter and thickness from coiled tubing.