Drilling tool internal blowout preventer for well drilling and method

The invention relates to a drilling tool internal blowout preventer for well drilling and a method. According to the technical scheme, a hole plate is arranged on a hole plate seat; a valve body is arranged on the lower portion of the hole plate; the lower middle portion of the valve body and a body form an airtight containing cavity, and a reset spring is mounted in the containing cavity; a communicating hole is formed in the lower portion of the containing cavity; a channel is formed in the lower portion of the body and internally provided with a filter plate; a plugging head is arranged onthe upper portion of the valve body; the upper portion of the plugging head is an upwards-bulged cone, the middle of the plugging head is cylindrical, and the lower portion of the plugging head is a conical groove; and a replacement plugging block is fixed to the middle of the plugging head through screws, and the section shape of the plugging block is a hollow trapezoid. The drilling tool internal blowout preventer has t