Packer and unsealing method thereof

A packer, comprising:

• a central tube (1), an outer surface of which is provided with a first prefabricated groove (11);
• a rubber cylinder unit (2) arranged on the central tube (1), comprising a rubber cylinder assembly (21), and an upper rubber cylinder seat (22) and a lower rubber cylinder seat (23) arranged at both ends of the rubber cylinder assembly (21), respectively, a slot (221) being formed in an inner wall surface of the upper rubber cylinder seat (22);
• an upper anchoring unit (3) and a lower anchoring unit (4) arranged at both ends of the rubber cylinder unit (2), respectively;
• and
• an unsetting mechanism (5), comprising a connecting sleeve (51) arranged between the upper anchoring unit (3) and the upper rubber cylinder seat (22), and an unsetting block (52) extending through a wall of the connecting sleeve (51) in a radial direction,
• wherein the unsetting block (52) is configured to engage with the slot (221) at a radially outer side thereof in an initial state, so that the upper rubber cylinder seat (22) is fixed to an upper cone (31) of the upper anchoring unit (3) in an axial direction, and engage with the first prefabricated groove (11) at a radially inner side thereof through a lifting movement of the central tube (1), in order to be disengaged from the slot (221), whereby the upper rubber cylinder seat (22) is axially movable relative to the upper cone (31) to unset the rubber cylinder unit (2), and
• a lower cone (41) of the lower anchoring unit (4) and the upper cone (31) are configured to move upward and downward respectively through the lifting movement and a pressing-down movement of the central tube (1), thereby releasing the lower anchoring unit (4) and the upper anchoring unit (3) respectively.