A nanofluid preparation method (100) from biogenic material is provided. The method includes the steps of:



(a) Treating (120) biogenic material with a strong acid to remove metal impurities;
(b) Heating (140) the treated biogenic material at a first temperature between 150° C. and 500° C.;
(c) Heating (150) the treated biogenic material at a second temperature above 600° C. to pyrolyze the treated biogenic material;
(d) Grinding (160) the pyrolyzed biogenic material to obtain nanoparticles of biogenic material; and
(e) Mixing (180) nanoparticles of biogenic material with an organic solvent to form a nanofluid, said organic solvent including a low polarity solvent.




A nanofluid obtainable by the nanofluid preparation method and the use of such a nanofluid for reducing fines migration or enhanced crude oil recovery are also provided. A system for enhanced crude oil recovery from a reservoir well is also provided.