Patent ID: 7497266

Claim:
A method for circulating out a formation influx from a subterranean formation below a subsea blowout preventer, comprising: letting gas associated with a formation influx into a well escape from below a subsea blowout preventer to a riser connected to the subsea blowout preventer; adjusting the level of a liquid/gas interface between a liquid in a lower part of the riser and gas at atmospheric pressure in an upper part of the riser to maintain a bottom hole pressure between formation fracture pressure and pore pressure; allowing the gas associated with the influx to collect in the upper part of the riser above an outlet in the riser, said outlet being substantially below seawater level and above seabed; pumping liquid out the outlet by way of a subsea pump connected by a flow return line to the outlet; and venting the gas collected in the upper part of the riser at atmospheric pressure at the upper end of the riser.