Abstract: A blowout preventer assembly for sealing off a well blowout within the confines of the drill stem is disclosed. The blowout preventer assembly comprises an elongated collar member which is located around and is slidable along a section of the drill pipe. Each end of the collar member has an expandable portion made of rubber or the like, which is capable of being expanded to the width of the drill pipe casing. Fixedly attached to the section of drill pipe at a location above the slidable collar member is a rigid metal collar section having around its circumference a plurality of equally-spaced wing flanges tapering down from a right angle at the top of the fixed collar to a slope at the lower end thereof.

Abstract: A blow out preventor assembly for attachment to the drill stem and being placed within the drill casing during well operations provides a bottom seal assembly having an attachment for slideably attaching the bottom seal assembly peripherally to a section of drill stem with the bottom seal assembly having at least one flow opening allowing oil, gas and drilling fluids to pass therearound. The upper portion of the bottom seal assembly forms a valve which cooperates with a provided port-ring mounted above the bottom seal assembly and having an outer diameter substantially equal to the diameter of the casing. The port-ring forms a flow closure between the drill stem and casing, and has at least one flow opening therethrough and a valve seat at the valve opening adapted to receive the valve portion of the bottom seal assembly. Upper and lower seat rings provide gravitational supports to the port-ring and bottom seal assemblies respectively.