External casing packer refers to a downhole tool connected to the downhole pipe string to isolate the oil pipe and the casing of the oil and gas well or the annular space of the open hole wall.

The working principle of the  External casing packer: after the hydraulic expansion packer goes down to the design depth, it is pressurized from the oil pipe, and the high-pressure liquid acts on the inner cavity of the rubber cylinder through the pressure-transmitting pores inside the packer, throttling the pressure difference. Under the action, the rubber cylinder expands to seal the annulus of the oil sleeve. When the oil pressure is released and the pressure of the oil jacket is balanced, the rubber cylinder shrinks back to its original state by its own resilience to achieve unsealing. After the compression packer goes down to the design depth, it is pressurized from the oil pipe, and the high-pressure liquid acts on the piston mechanism through the pressure-transmitting pores inside the packer. null. When the oil pressure is released and the pressure of the oil jacket is balanced, the rubber cartridge can be unsealed by restoring its original state by its own resilience.