Patent ID: 8851181

Claim:
A method for removing a fluid influx from a wellbore, the wellbore drilled using a drill string having an internal passage therethrough, the wellbore having a wellhead disposed proximate a bottom of a body of water disposed thereabove, a fluid outlet of the wellbore coupled to an inlet of a mud return pump, an outlet of the return pump coupled to a return line to the water surface, the method comprising: detecting the influx; diverting flow from the wellbore from the return pump to a choke line when the influx reaches the wellhead; operating a choke in the choke line so that a substantially constant bottom hole pressure is maintained, while continuing fluid flow into the drill string, the bottom hole pressure being less than a hydrostatic pressure that would be exerted by a column of the fluid flowing into the drill string from a surface of the water to a bottom of the wellbore; and redirecting fluid flow from the wellbore to the return pump inlet when the influx has substantially left the well.