Structure:

The self expanding packer when encountering oil and water mainly consists of a coupling, a central pipe, a pressure cap, a retaining ring, an oil absorbing and water absorbing expansion rubber cylinder, a connecting sleeve, a short joint, etc., which can be directly connected to the casing string. 

Working principle: When the packer is lowered into the well, the formation water (oil) comes into contact with the surface of the sealing cylinder. The sealing cylinder expands in large volume when it encounters water and oil, thus tightly squeezing the wellbore wall, 

Implement automatic sealing, which saves both manpower and time.