Patent ID: 7591315

Claim:
A well drilling assembly for drilling wells subsea with a drilling rig including an upper riser and a lower riser extending between the drilling rig and a well bore, and an upper string of drill pipe and a lower string of drill pipe extending between the drilling rig and the well bore, the well drilling assembly comprising: a subsea riser disconnect for connecting the lower riser extending downward through a seabed and into the subsea well bore with an upper riser extending downward from the drilling rig to the subsea riser disconnect, the lower riser being secured within the well bore, such that the subsea riser disconnect may be selectively activated by axial movement of the upper riser relative to the lower riser to disengage a lower end of the upper riser from an upper end of the lower riser; a subsea riser valve to seal off an interior of the lower riser secured within the well bore, the lower riser extending downward through the seabed and into the subsea well bore, the upper riser extending downward from a drilling rig to the lower riser, the subsea riser valve being selectively operable from the drilling rig; and a drill pipe disconnect for connecting the lower string of drill pipe with the upper string of drill pipe, the lower string of the drill pipe extending downward from the drill pipe disconnect through the well bore, the upper string of drill pipe extending downward from the drilling rig to the drill pipe disconnect, such that the drill pipe disconnect is selectively operable to disengage a lower end of the upper string of drill pipe string from an upper end of the lower string of drill pipe.