A casing head[1] is a simple metal flange welded or screwed on to the top of the conductor pipe (also known as drive-pipe) or the casing and forms part of the wellhead system for the well.

It is the primary interface for the surface pressure control equipment, such as the blowout preventers (for well drilling) or the Christmas tree (for well production).

The casing head, when installed, is typically tested to very strict pressure and leak-off parameters to insure viability under blowout conditions, before any surface equipment is installed.

See also