Synthesis of cost-effective Si-CQD for effective oil separation from core rock

Nanomaterials (NMs) based on carbon are suitable candidates for separating oil from core rock. Nowadays, the application of carbon-based NMs to enhanced oil recovery (EOR) is far less. The production of NMs based on carbon (water-wet) is of great importance due to the high recovery they create in reservoirs. The purpose of this study was to change the wettability of oil-wet (OW) carbonate rock (CR) towards water-wet (WW) conditions using cheap synthetic materials. In this regard, the effect of three quantum carbon dots (CQDs) on saltwaters has been used. The CQDs were synthesized by hydrothermal procedure and tetraethyl orthosilicate (TEOS) was used as the initial source of carbon. In this regard, Si-CQDs indicated great colloidal sustainability in saltwaters solutions. Therefore, to determine the morphological characteristics and structure of the synthesized NMs, Energy Dispersive X-ray (EDX), Scanning Electron Microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were done. The stability of NMs was investigated using the zeta potential (ZP). The new compound showed acceptable results at a very low concentration of 100 ppm. The findings indicated that the nanofluid (100 ppm SiCQDs + Seawater (SE)) reduced the interfacial tension value from 23.34 mN/m to 7 mN/m. Also, the results showed the solution of SE + 100 ppm Si-CQDs improved the oil recovery by 24 % and 23 %. Generally, this paper opens the door for the development of carbon-based NMs with the ability to absorb sediments in the porous media of the reservoir for the efficient separation of oil from core rock. Generally, our analysis supports the use of Si-CQDs as an efficient and economical additive for further oil recovery in carbonate reservoirs.