Good news! JST successfully got the authorization of invention patent on a Secondary Pack Off Sealing Structure in USA by United States Patent and Trademark Office in July, 2021.

During the drilling operation and oil and gas testing, the casing head slip hanger is the basic part of wellhead equipment, which is installed at the upper end of casing string to hang casing strings of each layer and seal the annular space between casings of each layer. As the main seal of slip type casing head, the performance of pack off seal directly affects the application range and normal use of casing head.

In order to overcome the defects in the prior design, this invention provides a slip seal structure, which can meet the requirements of using slip casing heads under the working conditions of 15000PSI high pressure and PU temperature grade (-29℃~121℃).  The pack off seal structure of the present invention will have a very excellent application prospect.