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

Abstract In recent years, the screw pump is used as a new artificial method for it has the advantages of less investment, simple device structure, conventional operation, obvious energy saving and strong adaptability. It could reduce the cost of production effectively and improve production efficiency. Now it has become the main method of oil field mining machine. With the maturity of the ground drive screw pump oil recovery technology, many new forms of injection-production technology gradually applied to the screw pump well, such as, the downhole double screw pump oil-water separation system. For the torque which load on the whole system increases considerably than conventional screw pump, Higher mechanical property requirement of the supporting hollow sucker rod is needed, the failure area mainly concentrated on the screw thread joint. The Stress analysis was applied to the 34 hollow sucker rod which is supported on the on and off attachment of the downhole double screw pump oil-water separation system. According to the stress analysis results, shape optimization was applied on the root shape of the screw thread, the stress distribution of the screw thead on hollow sucker rod joint was improved, the mechanical property of the screw thread joint of hollow sucker rod was improved.