WELL CEMENTING PLUG ASSEMBLIES AND METHODS

摘要

An improved well cementing plug assembly adapted to be connected to a string of drill pipe or a circulation tool for use in a pipe during the cementing of the pipe in a well bore is provided. The top and bottom plugs are selectively releasable by activating balls dropped into the plug assembly. Different sizes of plugs can be used utilizing the same inner tubes and other assembly parts, and the top plug slides on its inner tube when a pressure differential is exerted on it thereby insuring a seal between the top and bottom plugs when the plugs are landed on a float shoe or the like.