Strength Analysis Of Oil Tube In Viscous Oil Of CO₂ Injection

The technology of CO₂ injection displacement has become increasing popular in heavy oil recovery.However,the corrosion problem of CO₂ can easily lead to the failure of oil pipe and cause huge economic losses.Meanwhile,it will result in a great waste of resources,if replacing the oil pipe with small corrosion defect too early.Thus,it is of great significance to conduct strength analysis on the oil pipe with corrosion defects.At first,this paper carries out the mechanical analysis of the tubing operation in the CO₂ injection displacement heavy oil well.By establishing a temperature distribution model of vertical tubing and a tubing mechanics model with packer operation,the method of calculating axial load and internal pressure load is obtained.In addition,with the application of ANSYS,the ellipsoidal defect model and the grooving defect model are set up.Referring to the parameters of Tahe some oilfield,this paper explores the up stroke and the down stroke of sucker rod respectively,to find out the variety law of the maximum equivalent stress caused by these two defections with the tubing depths.Finally,from the result of FEM calculation,it confirms the variety law of maximum Mises stress with the defect size?defect length,defect circumferential width,and defect depth?,tubing pressure and tubing axial force to accomplish the strength analysis on the oil pipe with corrosion defects,Through the BP neural network,the strength of the corrosion resistant tubing is predicted,which can be used to provide evidence for safety assessment.