The invention provides a ball seat type rubber plug
system for liner cementing. The ball seat type rubber plug
system comprises a
drill rod rubber plug, a
tail pipe rubber plug and a bearing seat (4), wherein the
drill rod rubber plug is fed from a well mouth at the time of mud displacement, the
tail pipe rubber plug is placed below a feeding tool, and the bearing seat (4) is located at the bottom of a
tail pipe. The ball seat type rubber plug
system is characterized in that the tail pipe rubber plug is a ball seat type tail pipe rubber plug, an expansion ball seat (13) is installed at the bottom of the tail pipe rubber plug, the bottom end of the expansion ball seat (13) is of an elastic closing-in structure, and the elastic closing-in structure is opened due to deformation when pressure meets the needs. By adopting the ball seat type rubber plug system provided by the invention, the ball falling time is reduced, the
collision frequency between the ball and tail pipe
bunches in the ball falling process is reduced, the difficulty of easiness in sticking and blocking when
tripping balls in a extended reach well pass through a building section or tangent section at the bottom of the tail pipe is solved, the
operation time is saved, the balls are protected, the sealing effect is improved, the displacement efficiency is effectively improved, the well cementation success rate is improved, the drilling time is saved and the drilling cost is lowered.