High pressure well cementing plug assembly

摘要

A high pressure well cementing plug assembly (10) for use in a pipe (12) during the cementing of the pipe in a well bore (14) has top (20) and bottom (24) cementing plugs each including a high strength inner tube (62; 80) for supporting high differential pressures exerted on the plugs. The bottom end of the inner tube (80) of the bottom plug (24) is adapted to supportingly engage a float shoe or the like upon landing. Also, the bottom end of the inner tube (62) of the top plug (20) and the top end of the inner tube (80) of the bottom plug (24) are adapted to supportingly engage each other when the top plug (20) lands on the bottom plug (24). The high strength inner tubes (62,80) support high pressure differentials exerted on the plugs and prevent the plugs from collapsing or otherwise being damaged. <MATH>