Sanaz samaleh - Master student, Faculty of Mining, Petroleum Engineering and Geophysics, Shahrood University of Technology
Ahmad Vaezian - Assistant Professor, Faculty of Mining, Petroleum Engineering and Geophysics,Shahrood University of Technology
Mehrdad Soleimani Monfared - Assistant Professor, Faculty of Mining, Mining Exploration, Shahrood University of Technology
Yousef shiri - Associate Professor, Faculty of Mining, Petroleum Engineering and Geophysics,Shahrood University of Technology

The use of nanomaterials in nanoflooding is an emerging issue in oil recovery. In this article, we analyze the methods for preparing nanofluids and creating stable suspensions. Among the two common methods for the preparation of nanofluids, two - step method for the production of metal oxide nanoparticles are suitable and it is still a challenge to prepare a uniform nanofluid with long-term stability, low agglomeration, and lack of influence on thermophysical properties. Three methods have been used in the preparation of stable nanofluids: Surfactant: A critical micelle concentration must be observed to prevent rapid deposition of nanoparticles. PH control: In general, the value of zeta potential is obtained by adjusting the pH value according to a small volume fraction. Ultrasound: which has been shown to affect zeta potential and nanoparticle size. In the present study, the method of preparation of nanofluids of alumina, titanium, silica, zinc oxide, copper oxide and iron oxide are discussed. To find a suitable method for the preparation of stable nanofluids, the reports are thoroughly analyzed and and the results of the research are compared.

Nanofluid,Oil recovery,Surfactant,Acidity,Ultrasonic, stability,