Research on High Strength Casing Suitable for Working Condition of Staged-fracture Exploitation of Shale Gas

During the process of staged-fracturing in the shale gas well,the casing is being loaded with periodic and complex stress,which may very possibly cause damage and structural failure thereof.Researched and analyzed via the circulating hydraulic pressure test and the collapse test are the circulating internal pressure-resistance,the fatigue resistance and the collapse resistance of the TP110T hi-strength casing,and the key factors as affecting the performance of the pipe such as steel grade,microstructure,size and residual stress,etc.Accordingly relevant optimization method is proposed to enhance the service performance of the casing as used under the complex staged-fracture working condition, which provides certain technical support for the shale gas production.