A method of drilling a bore hole in a fractured formation. A drill pipe is deployed into the borehole, whereby an annular space is formed between the drill pipe and the borehole wall. A drilling fluid is pumped, by means of primary pumps, into the borehole via an internal conduit of the drill pipe and a drill pipe fluid outlet present in the vicinity of a distal end of the drill pipe. The annular space is pressure sealed using a pressure seal such as a rotating head on a BOP. A well control fluid is pumped into the annular space via a well control conduit that fluidly connects the annular space, in a location between the pressure seal and the drill pipe fluid outlet, to a backpressure system. The well control fluid is pressure-balanced against the pressure seal and the backpressure system.