Patent ID: 7861773

Claim:
A retrievable bridge plug, comprising a setting and anchoring mechanism, a locking and releasing mechanism and a sealing and anti-adhering mechanism, wherein (1) the setting and anchoring mechanism comprises an upper connector, a connector, a mandrel, an anchor cone, an anchor and an anchor sleeve; the upper connector connects to the connector through a pin, and the connector connects with the mandrel through a thread; a weak point of an annular recess is set at an upper portion of the mandrel, which controls a setting force of the bridge plug; on an outside surface of the anchor, there is a set of teeth which are reverse in direction a tooth-tip angle thereof ranges from 85-100Â°; There is a dovetail slot for a sliding connection between the anchor cone and anchor; the anchor is embedded into an open window of the anchor sleeve; a cone angle Î² of the anchor cone is 8-10Â°; an angle Î³ between two profile surfaces and outside surface of the anchor is 28-35Â°; (2) the locking and releasing mechanism comprises a releasing sleeve, a locking piece, a lock sleeve, an open lock ring, a mandrel and an anchor cone; the lock sleeve is embedded into the anchor cone, both of which are connected with the locking piece in the shape of an arc; a cross section of the locking piece is a combination of a rectangle and a trapezoid, wherein the rectangle part is assembled into a rectangle window of the anchor cone and the trapezoid part is assembled into a trapezoid groove of the lock sleeve; an inner diameter of the releasing sleeve is equal to an outer diameter of the locking piece; unidirectional thick sawtooth threads with same pitch are set on an outside surface of the open lock ring and inside the lock sleeve; unidirectional thin sawtooth threads with same pitch are set inside the open lock ring and outside the mandrel; and left-hand threads for releasing are set at an upper portion of the releasing sleeve; and (3) the sealing and anti-adhering mechanism comprises a rubber cylinder, a slide bushing, a sealed mandrel and an anti-adhering layer; the rubber cylinder is installed on the sealed mandrel, and the slide bushing is installed within the sealed mandrel and keeps sealed with the sealed mandrel via an O-ring; one end of the slide bushing is equipped with a circlip structure and a liquid discharge hole; an inside of the slide bushing is equipped with an annular recess; a lower portion of the sealed mandrel is conical, which has an anti-adhering layer set on its surface; and the anti-adhering layer is made of perduren.