| 摘要 |
<p>A subsea wellhead structure including a casing hanger having an exterior downwardly facing shoulder for landing within a well bore, a central bore, means for connecting a casing thereto, an upper exterior surface tapering downwardly and outwardly, and an external surface below said shoulder tapering downwardly and inwardly for centering said hanger on landing, a seal assembly with a metal seal sleeve having downwardly extending fingers, an internal metal annular bulbous sealing surface and an external metal cylindrical sealing surface, means for latching said seal sleeve in sealing position, a protector sleeve and means for releasably securing said protector sleeve to said seal assembly and said latching means, the latching means including retaining means preventing premature setting or movement of the latching means prior to the setting of said sealing means. The subsea wellhead structure is adapted to be lowered into the wellhead housing on a running tool which has an adapter ring supported thereon with external threads and an external recess, an internally and externally threaded split ring threaded onto said adapter ring and threadedly engaging said casing hanger, the rotation of said running tool threading said adapter ring through said split ring to allow said split ring to retract into said adapter ring recess thereby allowing release of said casing hanger from said running tool after landing, means on said running tool for supporting the protector sleeve, the seal assembly and the latching assembly thereon for running into the well bore on the running tool with said casing hanger and for lowering and rotating the seal sleeve with the fingers scraping the sealing surface surrounding the casing hanger to clean the sealing surface so that said sealing surface portions of said sealing sleeve provide a metalto-metal seal between the external tapered surface of the casing hanger and the cleaned sealing surface, for release and setting the latching means and for release and recovery of said sealing assembly and said latching assembly by right hand rotation of a retrieving tool.</p> |
