Abstract: A marine riser anticollapse valve is disclosed for preventing a marine riser from collapsing under external sea water pressure in the event of a sudden loss of internal drilling fluid pressure. An external valve structure is provided for each of a plurality of openings in the wall of a riser pup joint. Each of the valve structures includes a cylinder having an opening in communication with a body wall opening. A piston in each cylinder is subject to sea water pressure but is prevented from opening when riser bore pressure of a sufficient magnitude is applied internally to the piston via the pup joint opening and cylinder opening. When the riser bore pressure falls, the piston is driven to an open position allowing sea water to enter the riser.

Abstract: A system adapted for alternative use as a diverter or a blowout preventer for a bottom supported rig and adapted for positioning beneath a rotary table of the drilling rig is disclosed. The system comprises a fluid flow controller and at least two bases adapted for being alternatively removably secured to the controller. When the first base is in combination with the fluid flow controller, the system may be used only as a diverter and when the second base is used in combination with the fluid flow controller the system may be used only as a blowout preventer. A method according to the invention includes steps for installing the system adapted for alternative connection as a diverter or a blowout preventer for a bottom supported drilling rig after structural casing has been set in a borehole.

Abstract: A system and method for installing a fluid flow controller and telescoping spools beneath an offshore bottom supported drilling rig rotary table is disclosed. Upper and lower telescoping spools are provided for initially connecting a Diverter/BOP convertible fluid flow controller between structural casing in the well and a permanent housing beneath the drilling rig rotary table.A system and method for installing a fluid flow controller and a lower telescoping spool beneath and offshore bottom supported drilling rig rotary table is disclosed.This alternative embodiment of the invention provides the lower telescoping spool connected between the diverter/BOP convertible fluid flow controller and structural casing in the well. The top of the controller is connected to the permanent housing beneath the drilling rig rotary table. Additionally, a diverter system, a low pressure blowout preventer system and a high pressure blowout preventer system are disclosed for both embodiments.

Abstract: A system and method for installing a fluid flow controller and telescoping spools beneath an offshore bottom supported drilling rig rotary table is disclosed. Upper and lower telescoping spools are provided for initially connecting a Diverter/BOP convertible fluid flow controller between structural casing in the well and a permanent housing beneath the drilling rig rotary table. Clamp means are provided for clamping the rig vent line to an opening in the housing wall of the fluid flow controller during drilling of the borehole through the structural casing in preparation for setting and cementing the conductor casing. In that mode, the system is adapted as a diverter system. After the well is drilled for the conductor casing and the conductor casing is cemented and cut off at its top, a mandrel is fitted at the top of the conductor casing to which the lower end of the lower spool may be connected.

Abstract: Apparatus is disclosed which is adapted for connection to a drilling conduit beneath a drilling rig floor for diverting pressurized well bore fluid in the conduit from the rig and sealing the annulus between a pipe or other object and the conduit or closing the vertical flow path of the conduit in the absence of any object in the conduit. The apparatus includes a housing, an annular packing element and two annular pistons. The housing is provided with two outlet passages in its wall. A first piston covers one outlet passage in the housing wall for preventing fluid communication between that outlet passage and the interior of the housing when it is in a nonactivated position and for aligning a first hole in the piston wall with the outlet passage for allowing fluid communication when the piston is in an activated position.