Changes proposed to improve leak resistance of casing due to mismatching thread leads
The leak resistance of the API buttress casing connection can be improved by mismatching the thread leads between coupling and casing members. These modifications can be made such that the improved product will meet all present API standards and will not affect interchangeability with present products or require changes in gages or tooling. The buttress thread casing connection is one of the most widely used oil well casing connections. It is now an American Petroleum Institute (API) standard connection. It is listed in API Standard 5B and titled ''Buttress Thread Casing''. This connection was patented by Samuel Webb in 1956, assigned to United States Steel. The purpose of the invention was to develop a threaded tubular connection as strong as the pipe body in axial tension without having to upset the tube ends. The inventor also recognized that a connection needed to be leak tight even when carrying high tensile loads. The patent states, ''There has also been a tendency for conventional joints to leak when subjected to high pressures when bearing heavy loads and it is imperative that the casing joints do not leak under such conditions''. This latter point is the subject of this article.
- Research Organization:
- Tublar Corp of America, Houston, TX
- OSTI ID:
- 6718645
- Journal Information:
- Oil Gas J.; (United States), Vol. 82:4
- Country of Publication:
- United States
- Language:
- English
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