Experimental and numerical simulation research on counter-current imbibition distance in tight oil reservoirs

•The dynamic counter-imbibition processes along the core samples were monitored in-time using low-field NMR technique.•The imbibition front and oil recoveries within individual layers along the core sample were determined.•Nanofluid advanced farther than DI water along the core sample during the counter-imbibition process.•The nanofluid on interfacial properties and rock pore structure are the dominant mechanism for nanofluid in EOR.