CONTINUOUS FLOW DRILLING SYSTEMS AND METHODS

摘要

In one embodiment, a method for drilling a wellbore includes injecting drilling fluid into a top of a tubular string disposed in the wellbore at a first flow rate and rotating a drill bit, wherein the tubular string includes the drill bit disposed on a bottom of the string, tubular joints connected together, a longitudinal bore therethrough, a port through a wall thereof, and a sleeve in fluid communication with a hydraulic chamber and operable between an open position where the port is exposed to the bore and a closed position where a wall of the sleeve is disposed between the port and the bore; and injecting drilling fluid into the port at a second flow rate while adding a tubular joint or stand of joints to the tubular string, wherein injection of drilling fluid into the tubular string is continuously maintained between drilling and adding the joint or stand to the tubular string.