Single-stage double-plug casing cementing is the most commonly used cementing method for offshore drilling. It uses double-casing rubber plugs (top and bottom plugs) for cementing. The process flow is shown in the figure. Generally, common casing plugs are used for cementing on jack-up platforms or jackets, while SSR plugs are used for cementing on floating platforms.

Casing rubber plug: mainly used for casing cementing on jack-up platforms and jackets. The bottom plug (red) is used to isolate the cement slurry from the front fluid, preventing the front cement slurry from being damaged before it exits the casing hoop. Pollution. The top plug (yellow) is used to separate the displacement fluid from the cement slurry to prevent the subsequent cement slurry from being polluted by the displacement fluid. At the same time, the top plug is also used to bump pressure to indicate the end of the cementing slurry replacement. The bottom plug is located behind the floating hoop, and the breakdown pressure of the rubber is about 400psi.
The SSR plug group is mainly used for casing cementing of semi-submersible platforms, which allows the cement slurry to be pumped into the well through the drill pipe without the need to run all the casing from the drill floor to the seabed. The drill pipe plug is put in through the drill pipe cement head, which can scrape off the cement slurry in the drill pipe and shear to release the SSR casing plug. The function of the SSR casing plug is the same as that of the aforementioned casing plug.