Selection of premium connection for high temperature and high pressure well
High temperature and high pressure wells put forward higher requirements for the premium connection. The manufacturer of the premium connection should not only pay attention to the preparatory work, screw joint design and quality assurance procedures in the early planning stage, but also run through all links of product processing, transportation and well pad.
Premium connection with double sealing surface
The casing with API standard thread connection is difficult to meet the production demand in many cases. In addition to meeting the joint performance, premium connection also needs to have good sealing performance under extreme environment and composite load.
Processing program of premium connection
The processing technology of the premium connection thread is realized by the processing program. CNC machine tools, the systems used and the specific processing procedures are different. The following common problems should be paid attention to when programming:
Processing characteristics and difficulties of premium connection
Premium connection includes thread, sealing surface and shoulder. The processing technology is complex. For example, when the coupling is processed, the distance between the thread and the sealing surface is relatively close, and a special undercut is generally designed at the end of the thread.
Direct connection premium connection
The feature of the direct connection type premium connection is that the tubing and casing are not connected by coupling, and the internal and external threads are directly processed at the end of the tubing and casing.
Selection of main sealing structure of premium connection
The sealing performance of the premium connection depends on the design of its main sealing structure. At the same time, the bonding of the premium connection mainly occurs on the main sealing surface.
The basic method of optimizing the sealing structure of premium connection
The sealing performance of premium connection mainly depends on the form of main sealing structure, the size of sealing interference and the sealing effect of auxiliary sealing structure.
Sealing structure of premium connection
Premium connection generally has multiple seals, including main seal (mainly realized by metal / metal radial seal structure), auxiliary seal (generally realized by torque shoulder), elastic seal (generally realized by teflon seal ring), etc. in addition, although the thread does not play a major role in sealing, it still has a certain sealing effect. Because of these sealing structures, special threaded joints generally have good sealing performance.
Sealing mechanism of premium connection
Premium connection is different. The sealing function of this kind of thread is no longer realized by thread matching, but a special structure is designed for this purpose, generally a metal sealing structure.
Relationship between sealing performance and structure of premium connection
The sealing performance of the premium connection casing joint is closely related to its own structure, such as the form of metal sealing structure, the size of sealing interference, the form of auxiliary sealing structure, etc.