DELAYED OPENING BALL SEAT

摘要

A removable ball seat assembly is disclosed. It features a solid ball seat backed up by segmented dogs pinned to each other and mounted under the ball seat. Upon actuating a downhole tool with fluid pressure applied to a ball on the seat, the pressure is increased and the ball and seat move at a regulated rate. The dogs reach a recess and the ball moves through the seat. Subsequent, larger balls can pass through the seat, with the dogs in th e recess, at much smaller pressure drops than the original ball.