Continuous flow drilling systems and methods

Abstract

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. The tubular string includes: a drill bit disposed on a bottom thereof, tubular joints connected together, a longitudinal bore therethrough, and a port through a wall thereof. The drilling fluid exits the drill bit and carries cuttings from the drill bit. The cuttings and drilling fluid (returns) flow to the surface via an annulus defined between the tubular string and the wellbore. The method further includes rotating the drill bit while injecting the drilling fluid; remotely removing a plug from the port, thereby opening the port; 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. The injection of drilling fluid into the tubular string is continuously maintained between drilling and adding the joint or stand to the drill string. The method further includes remotely installing a plug into the port, thereby closing the port. The first and second flow rates may be substantially equal or different.