Naked hole ball throwing open type annulus pressure drop tool

The invention discloses a naked eye ball throwing open type annulus pressure drop tool which comprises a shell, a movement mechanism and a power mechanism, and the movement mechanism and the power mechanism are arranged in the shell. The shell comprises a lower joint, a spiral outer cylinder and an upper joint which are in threaded connection in sequence; the movement mechanism comprises a body, a mandrel arranged in the body, a gear set and a bearing set. The power mechanism comprises a ball seat arranged on the connector side of the mandrel, a ball arranged in the ball seat, a rotor cap arranged outside the ball seat in a sleeving mode and a turbine set arranged outside the mandrel in a sleeving mode. The tool is started in a ball throwing mode, the function of reducing annulus pressure consumption while drilling is achieved, and therefore the risks of low-pressure stratum fracture and well leakage are reduced, and the yield increasing effect of a horizontal well is greatly improved. 本发明公开了一种裸眼投球开启式环空压降工具，包