Study On The Mechanism Of The Wear Between Casing And Sucker Rod In Three-dimensional Hole Well

Firstly, this thesis briefly analyzes the force condition of the casing and sucker-rod system, and sets thethree-dimensional simulation model which models the finite element of the off-center wear of casing andsucker rod in the well. And preliminarily estimate where the off-center wear may happen by increasing theload differently on the simulation moel. Then it comes to find out the force condition in different wells andwhere the off-center wear may happen by setting different finite element hole model and analogue simulating.Meanwhile it makes an lateral comparison. It makes a further study on the influence law between the differenthole track and the off-center wear in wells. It preliminarily comes to the conclusion that the more hole trackbending, the more easily the off-center wear happens. Finally, we can prevent the off-center wear after thestudy on its mechanism.The contact force between the sucker rod and vitta determines the degree of eccentric wear. This thesishas built a index named curvature to represent the borehole trajectory. And after the theoretical analysis, arelationship model between the curvature of well L, well C and the contact force has been made. We can fixthe cantact force between the vitta and sucker rod and its position by the borehole trajectory using this model.Setting the analytical model of the eccentric wear between the sucker rod and vitta in the Well S, Well Land Well C, We get the law between the borehole trajectory and location and degree of the eccentric wear inthe same type of wells in different oblique and the different type of wells in the same oblique. When thedeviation increases, the curvature of the sucker rod also inereases, and the contact force between the sucker rodand vitta also inereases. In this case, the eccentric weer between the vitta and sucker rod is more prone tohappen. After we install the centralizer on the sucker rod, we made a computation of the finite elementsimulation again. Then we can get the function and significance of the centralizer on preventing the eccentricwear between sucker rod and vitta. Centralizers can significantly reduce the contact force between the vitta andsucker rod, which can effectively prevent the eccentric wear.Lastly, we use the theory method and the finite element modelling method in the pratical well conditions.After comparing the two results that we got in the two methods, we found that the former result is close to thelatter one.