The Optimization of Casing Thread Types for Horizontal Tight Oil Wells in Mahu Oilfield, Xinjiang

To tackle the fracture failure of casing thread joints when running casing in horizontal tight oil wells in Mahu Oilfield, Xinjiang, numerical simulations of casing thread joints and full-scale experiments on casing were conducted to compare and analyze the connection strength and fatigue life of API-LC long round thread joints and TP-G2 special thread joints during the lifting and lowering process of casing running. The results of simulations and experiments showed that the stress of TP-G2 special thread joints was significantly lower than that of the API-LC long round ones under the same tension or compression forces, and further, the fatigue life of TP-G2 special thread joints was about 6.9 times of that of API-LC long round thread joints under the same cyclic and alternating tensile-compressive load. According to our research, TP-G2 special thread joints can play a better role than API-LC long round thread joints in meeting the technical demands for casing operation in horizontal tight oil wells in Mahu Oilfield, Xinjiang and in improving operation efficiency.