Configuration Optimization Design Of Directional Well Rod String Centralizers Based On The Prediction Of Wear Life

As the core component of rod pump well, the sucker rod and tubing string suffer complicated and long-time alternating loads when working. Coupled with the impact of directional wellbore bent,makes the rod-tubing eccentric wear a major failure mode of the directional well. Once the rod or tubing string is out of work,the well cannot work normally, and the crude oil production will be affected.At present,since the pump inspection cannot be predicted, the inspection for pumping wells are mostly occurred after the pumping wells have been out of work.The post-pump inspection cause the increasing of the pump inspection and the shut down days during the pumping inspection,and it will reduce the economic benefits of oilfields seriously.Aiming at the rod-tubing eccentric wear of directional wellls,the following contents was studied in this paper:Based on the simulation of the directional wellbore track and the analysis of the sucker rod string environment load,the “space beam element + spring element” finite element analysis model was established.And the simulation of contact position and pressure between the rod string and tubing string of directional wells was achieved.Based on the finite element simulation of the rod-tube contact results and combining with the energy wear theory, the computational model of transient wear amount between the rod string and tubing string in a swabbing cycle was established;The computational model of the sucker rod and coupling and centralizer wear life was established;The directional well sucker rod string stabilizer configuration method based on wear life prediction is proposed. The mathematical model of directional well sucker rod centralizer configuration optimization design was established.The corresponding software for directional well eccentric wear life and sucker rod centralizer configuration optimization design was programmed applying Visual Basic 6.0. This softwear can be used to guide the design of the centralizer configuration and provide a reliable design method for preventing the rod tubing eccentric wear and for predicting the pump inspection.