Stress Analysis of Hollow Sucker Rod Screw Thread Jiont and Shape Optimization of Screw Thread

With the maturity of surface driven rod screw pump production technology, many new forms of injection and production processes have been applied to screw pump wells, such as downhole oil water separation systems with twin screw pumps. Due to the significant increase in torque required to drive the normal operation of the entire system compared to conventional screw pump wells, higher requirements are placed on the mechanical properties of matching hollow sucker rods, and their failure parts during use are mainly concentrated at the joints. This paper analyzes the stress characteristics of the screw joint of a 34 mm diameter hollow sucker rod used in the downhole oil water separation system of a twin screw pump. Based on the analysis results, the shape of the screw root is optimized, improving the stress distribution of the screw joint threads of the hollow sucker rod, and improving the mechanical properties of the screw joint of the hollow sucker rod.