Study On The Sealing Device Of The Casing Of The External Pressure

In the current oil and gas field, the leakage of casing sealing does not only exert great influence on future construction, but also brings security issues for environment and society. From production and completion of casing, there are several factors that would affect sealing of casing connection, such as damages in the operation, manual damages, torque confirmation when screwing on the hydraulic tong, and cleanness between a connector and a sealing surface. As making the casing, it applies the internal pressure examination equipment to casing thread sealing performance in real time. However, it is figured out that some problems happen in the application of internal pressure examination equipmentincluding inconvenience operation, more time consuming, possible dropping fishing phenomenon and hard examination of small diameters casing. As the above mentions, it puts forward to a method for examination on casing threads sealing based on external pressure and finishes the design of the device.(1) It is invented that the external pressure method is to examine sealing performance for casing threads as disadvantages for internal pressure examination.(2) It is studied that sealing forms and mechanism of casing threads are in the current application. By the help of finite element stimulation, it analyzes the equivalent stress and contact stress when the internal and external pressure examinations are separately used. As a conclusion, the external pressure one is acceptable.(3) Based on the principle of BOP and current operating situation, the way and device of sealing examination are selected and then the design of mechanical structure is completed for the external pressure examination device on casing sealing threads.(4) It tells that the conjoint analysis of experimental data is done by the Mooney-Rivlin constitutive model, Ogden constitutive model and Yeoh constitutive model after the completion of simple tension and compression experiments. It is found out that the material characteristic of rubber core is illustrated clearly when Yeoh constitutive model is taken.(5) The structure design of sealing rubber core is achieved on the basement of theoretical investigation for important parameters of sealing structure. By means of finite element stimulation, the impact on sealing effect is researched by these parameters such as partial distance e, radius difference A, partial distance on forward face of pad iron et and outer arc radius of pad iron R.2. What’s more, the better dimension parameters are selected for the rubber core of device.(6) It is included that the design on the hydraulic cylinder structure and the hydraulic control system are completed. The strength of external shell in the bearing pressure parts, where stress concentration happens, is validated. It also gives that structure dimensions are optimized.