With the development of oil well gas drilling operations to more severe working conditions such as deeper, higher pressure and higher temperature, and the continuous improvement of oil drilling technology, conventional oil
casing pipe threads are difficult to meet the development needs of oil fields.
At present, there are more and more high-pressure oil and gas wells. The ordinary API threaded tubing can not meet the requirements of high-pressure sealing. For oil and gas wells with pressure higher than 28MPa, most of them choose gas-tight special buckle type tubing. As more and more H2S/CO2/Cl- containing oil and gas wells will be put into development, ordinary low-carbon low-alloy steel tubing cannot adapt to harsh corrosive environments, and the service life of tubing cannot meet the design requirements of oil and gas wells, so 9Cr, 13Cr. The application of corrosion-resistant material tubing such as 22Cr and 25Cr is also becoming more and more extensive.
