Managed pressure drilling system having well control mode

MANAGED PRESSURE DRIL L ING SYST EM HAVING VEL L CONTROL MODE A method of managing drilling pressures, comprising measuring a flow rate of a drilling fluid (60d) injected into a tubular string extending into a subsea wellbore (100) in a formation; measuring a flow rate of returns from a drill bit disposed on a bottom of the tubular string; comparing the returns flow rate to the drilling fluid (60d) flow rate to detect a kick; exerting backpressure on the returns using a first variable choke valve; and in response to detecting the kick: closing a blowout preventer of a subsea pressure control assembly (PCA) (lp) against the tubular string; and diverting the flow of returns from the PCA (lp), through a choke line having a second variable choke valve, and through the first variable choke valve.