The while-drilling annulus plugging device comprises an upper central
pipe and a lower central
pipe, a first liquid inlet hole and a setting liquid inlet hole are formed in the upper central
pipe, and a second liquid inlet hole is formed in the lower central pipe; the rubber sleeve is sleeved outside the central pipe to form a closed ring cavity; the upper rubber sleeve protection sleeve and the lower rubber sleeve protection sleeve are respectively sleeved outside the rubber sleeve and can axially move along the central pipe; the setting starting mechanism comprises a starting / closing
piston arranged in the annular space and used for controlling on-off of the setting liquid
inlet flow channel. The ball throwing unblocking mechanism comprises an unblocking
ball valve seat supporting sleeve, an unblocking
ball valve seat and an unblocking ball body, the unblocking ball body can block a
drilling fluid descending channel after being thrown in, and meanwhile, a pressure relief hole and a
check valve are arranged, so that one-way flowing of
drilling fluid is ensured; the ball injection setting mechanism comprises a ball injection setting connector and a setting
ball valve seat and is used for blocking a
drilling fluid descending channel in the
drill rod. The device is compact in structure and easy and convenient to operate, annulus plugging in the
deep sea drilling process can be effectively achieved, and high practicability and reliability are achieved.