Coring tool, coring method, and application thereof

A coring tool (1000), comprising a housing (100), a differential device (200) for selective force transmission and a core gripping device (300) for core cutting operations both arranged within the housing (100), and a coring bit (500) connected to a lower end of the housing (100),

• wherein the differential device (200) comprises a differential unit (210), and a suspension unit (260) arranged downstream of the differential unit (210), and the core gripping device (300) comprises a first core gripper (350), a second core gripper (360), and a shielding mechanism (310);
• when the coring tool is in a first state, the coring bit (500) is configured to perform coring operation, while the second core gripper (360) is shielded by the shielding mechanism (310);
• when the coring tool is in a second state, the first core gripper (350) is configured to move downwardly in response to a downward pressure from the differential device (200), thereby performing a first core cutting operation;
• when the coring tool is in a third state, the shielding mechanism (310) is configured to expose the second core gripper (360) in response to an upward pulling force from the differential device (200), thereby performing a second core cutting operation;
• and
• the suspension unit (260) comprises a first pressure-building mechanism (261), and a first positioning mechanism (270) arranged downstream of the first pressure-building mechanism (261), the first positioning mechanism comprising an outer positioning member (271), an inner positioning member (272), and a first actuating member (273) arranged therebetween, and a lower end of the first actuating member (273) being fixedly connected to the shielding mechanism (310);
• wherein in the first state, the first actuating member (273) is locked to the outer positioning member (271) through a second locking mechanism (275), and the inner positioning member (272) is connected to the outer positioning member (271) through a second shear pin (277);
• and
• in the second state, the first pressure-building mechanism (261) is actuated to shear off the second shear pin (277), thereby pushing the inner positioning member (272) to move downwardly to release the second locking mechanism (275), so that the first actuating member (273) transfers the downward pressure to the shielding mechanism (310).