Subsea well safing system

A subsea well safing system, comprising:

• a safing assembly comprising a lower safing assembly connected to a blowout preventer stack connected to a subsea well and an upper safing assembly connected to a marine riser;
• a safing assembly connector in a latched position interconnecting the lower safing assembly and the upper safing assembly providing a bore therethrough in communication with the marine riser and the well, the safing assembly connector operable to an unlatched position thereby disconnecting the upper safing assembly from the lower safing assembly;
• and
• an ejector device connected between the upper safing assembly and the lower safing assembly, the ejector device operable to push the upper safing assembly and the lower safing assembly apart and thereby physically separate the upper safing assembly and connected marine riser from the lower safing assembly.

A subsea well safing sequence, the method comprising:

• utilizing a safing assembly installed between a blowout preventer stack of a subsea well and a marine riser, the safing assembly comprising a lower safing assembly connected to the blowout preventer stack and an upper safing assembly connected to the marine riser forming a bore between the riser and the blowout preventer stack, wherein the lower safing assembly comprises lower slips and the upper safing assembly comprises upper slips;
• securing a tubular suspended in the bore with the lower slips at a position in the lower safing assembly;
• securing the tubular with the upper slips at a position in the upper safing assembly;
• shearing the tubular in the bore between the position in the lower safing assembly and the position in the upper safing assembly at which the tubular has been secured;
• and
• after shearing the tubular, physically separating the upper safing assembly and the connected marine riser from the lower safing assembly connected to the blowout preventer stack.