Stress Analysis of Sucker Rod and Application of Heavy-weight Rod in Directional Well

Changqing field is located in rough loess plateau area.Recently,in order to save ground surface construction cost and have easy management,cluster wells were drilled directionally in large area and the ratio of directional wells was up to 85%.In the process of production due to peculiarity of well holes,the stress of pumping rods had changed so complex that they would break and slip easily,thus wells production had been damaged.We have taken many measures to solve this problem and weighing under the rod was one of these solutions.After theoretical calculation and field tests the method has been applied extensively and confirmed that it has good effect and can prolong well repair free period.