| 摘要 |
In a subsea wellhead assembly, a connector attaches a production riser or subsea tree to a wellhead housing. The connector includes a piston that cams a plurality of dogs into and out of engagement with the wellhead housing while sliding axially upward and downward relative to the wellhead housing. The piston is typically actuated by injecting hydraulic fluid into either an upper chamber or lower chamber to move the piston axially up or down. While in the axially downward, or locked position, the piston houses an override chamber. Hydraulic fluid is injected into the override chamber to move the piston axially upward and unlock the connector when the seals of the lower chamber fail. |
