Downhole rotational flow gravity coupling type multiphase medium separation device for injection and production in same well

The invention discloses an underground rotational flow gravity coupling type multiphase medium separation device for injection and production in the same well. The device comprises a degassing structure and an oil-water separation structure, the degassing structure comprises a multi-channel end cover, a cyclone separation cavity, an upper connector, an oil filtering plate, an upper sleeve, a hollow spiral flow channel, a gas-liquid inlet cone and a one-way valve, and the oil-water separation structure comprises a reducing transition, a bridge type channel, a spiral flow channel, a slow flow cone, an oil-water separation cavity, a lower sleeve and an inverted cone; the degassing structure is used for separating a gas phase in the oil-water mixed liquid in advance by utilizing a gas-liquid separator, meanwhile, the gas phase is subjected to secondary treatment, and the separated oil-water mixed liquid is discharged into the oil-water separation structure; according to the oil-water separation structure, oil-wat