ROTATING BOP AND METHOD

摘要

A rotating blowout preventer and method is disclosed that includes a flexible bladder that defines a pressure chamber radially outwardly of the bladder for direct activation of the bladder to allow for gas tight sealing along the variable profile of drill pipe and the irregular shape of the kelly. The pressure chamber for activating the bladder is preferably defined within the rotating seal assembly. As well, the rotating seal assembly includes both the bladder and the bearings. A pressure drop element is included within the hydraulic flow line through the rotating seal assembly so that the upper seal and bearing have a significantly reduced pressure drop for increased lifetime operation. The rotating seal assembly is hydraulically secured within the rotating blow-out preventer housing, preferably by remote control, by means of a preferred single cylindrical latch piston that moves upwardly and downwardly substantially parallel to the well bore axis. The latch piston wedgeably moves latch dogs radially inwardly to effect latching. After the latch piston is moved from the latch position, the latch dogs move radially outwardly as the rotating seal assembly is lifted from the rotating blow-out preventer housing as by a rig cat line to thereby effect quick change out of the bearings and/or the bladder.