Method using nuclear magnetic resonance-displacement combined device to evaluate tight oil filling process

The invention discloses a method using a nuclear magnetic resonance-displacement combined device to evaluate a tight oil filling process. The method has the advantages that a nuclear magnetic resonance device is operatively connected with a core holding unit to use the nuclear magnetic resonance technology to online monitor a tight sandstone displacement process; the method uses fluorocarbon oil which does not contain a hydrogen signal to displace a core rich in formation water (containing the hydrogen signal), the volume of water which can be detected by the nuclear magnetic resonance is reduced constantly along with the constant proceeding of the oil displacing water process, and the changing process showing that the formation water in pores is constantly displaced by the fluorocarbon oil by the process that the signal amplitude in nuclear magnetic resonance test T2 spectrum during an experiment is constantly lowered; experiment data is processed and analyzed after the experiment, and the processing and ana