Multistage separation technology and device

The invention provides a multistage separation technology. Oil, gas, water and solids are separated through primary separation of a separating tube, secondary double separation of the separating tube, liquid-solid separation, third separation of the separating tube, primary cyclone separation, secondary cyclone separation, fourth separation of the separating tube, settling separation and cycling. A multistage separation device comprises a primary separating tube, an upper tube unit of a secondary separating tube, a lower tube unit of the secondary separating tube, a liquid-solid separator, a third separating tube, a cyclone I, a cyclone II, a fourth separating tube, a settling tube and a liquid storage tank. Oil, gas, water and solids are quickly separated by means of the characteristics of the pipeline, the density difference of phase media and dynamic separation, a conventional method of separating multiple phases by means of a container is broken through, an explosion failure mode of the pressure container