S seal and O ring both can be used for wellhead casing but they have different functions and suitable for different working conditions.

O ring is a static seal. It is suitable for lower pressure, small groove gap and smooth groove surface. O ring is usually combined with back up ring. But in hostile environment, such as H2S, high pressure, high and lower temperature, rough groove surface, o ring would not be suitable. Therefore people normally use S seal instead of o ring.

JST S seal elastomer provides high mechanical strength and wear-resistant properties. It has good resistance to various oilfield chemicals including H2S and amine corrosion inhibitors. It is also resistant to rapid gas decompression and is approved to many RGD specifications.

S seal is easy to install, even in a blind recess. The use of integral anti-extrusion springs in S seal eliminates the risk of these elements becoming dislodged or damaged during assembly. S seal anti-extrusion elements are bi-directional to prevent incorrect installation.

JST’s S seal uses HNBR85 material which is suitable for for H2S environment and LU temperature rating and 20000 Psi pressure rating. The material has been tested and approved by the third party Alpine.

Guangzhou JST Seal technology Co.,ltd is ISO/API/HSE registered manufacturer and supply wide range of elastomer seals and polymer seals that can be customized according to clients’ requirements.