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.

Abstract: A method for drilling a wellbore includes drilling the wellbore by advancing the tubular string longitudinally into the wellbore; stopping drilling by holding the tubular string longitudinally stationary; adding a tubular joint or stand of joints to the tubular string while injecting drilling fluid into a side port of the tubular string, rotating the tubular string, and holding the tubular string longitudinally stationary; and resuming drilling of the wellbore after adding the joint or stand.

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.

Abstract: Methods and apparatus enable reliable and improved isolation between two portions of a bore extending through a casing string disposed in a borehole. A downhole deployment valve (DDV) may provide the isolation utilizing a valve member such as a flapper that is disposed in a housing of the DDV and is designed to close against a seat within the housing. The DDV includes an operating mechanism for opening/closing the DDV. In use, pressure in one portion of a well that is in fluid communication with a well surface may be bled off and open at well surface while maintaining pressure in another portion of the casing string beyond the DDV.