The invention relates to the technical field of
oil field drilling liner cementing, in particular to a drilling liner rubber plug, a drilling liner rubber plug device with controllable breakdown pressure and an application method of the drilling liner rubber plug device. The upper body and the
lower body are used for bearing all parts of the
tail pipe rubber plug and arranged on the upper portion and the lower portion of the
tail pipe rubber plug respectively. The
shear pin is used for connecting the
tail pipe rubber plug and the central pipe, and when the pressure applied to the tail pipe rubber plug by the
drill rod rubber plug reaches a first preset pressure value, the
shear pin is
cut off; the emergency shearing sleeve is fixed to the middle of the cavity of the
lower body through the emergency pin, when the pressure applied to the tail pipe rubber plug by the
drill rod rubber plug reaches a second preset pressure value, the emergency pin is
cut off, and the emergency shearing sleeve continues to move downwards along with the
drill rod rubber plug. When the tail pipe rubber plug body is blocked in the tail pipe and cannot be smoothly jacked through, an emergency breakdown mechanism can be started, and excessive
cement paste is effectively prevented from being retained in the tail pipe.