Effect of salinity on hydroxyapatite nanoparticles flooding in enhanced oil Recovery : A mechanistic study

Fluid-fluid interactions can affect any enhanced oil recovery (EOR) method, including nanofluid (NF) brine-water flooding. Flooding with NFs changes wettability and lowers oil-water interfacial tension (IFT). Preparation and modification affect the nanoparticle (NP) performance. Hydroxyapatite (HAP) NPs in EOR are yet to be properly verified. HAP was synthesized in this study using co-precipitation and in situ surface functionalization with sodium dodecyl sulfate in order to investigate its impact on EOR processes at high temperatures and different salinities. The following techniques were employed, in that sequence, to verify its synthesis: transmission electron microscopy, zeta potential, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, particle size analysis, and energy-dispersive X-ray spectra. The outcomes showed the production of HAP, with the particles being evenly dispersed and stable in aqueous solution. The particles' surface charge increased from -5 to -27 mV when the pH was changed from 1 to 13. The HAP NFs at 0.1 wt % altered the wettability of sandstone core plugs from oil-wet at 111.7 to water-wet at 9.0 contact angles at salinity ranges of 5000 ppm to 30,000 ppm. Additionally, the IFT was reduced to 3 mN/m HAP with an incremental oil recovery of 17.9% of the initial oil in place. The HAP NF thus demonstrated excellent effectiveness in EOR through IFT reduction, wettability change, and oil displacement in both low and high salinity conditions

Influence of (3–Aminopropyl) triethoxysilane on silica nanoparticle for enhanced oil recovery

A substantial volume of oil is trapped in the reservoir after the primary and secondary recovery processes because of pressure and reservoir heterogeneity. Experimental results have indicated that silica nanoparticle (SNP) flooding is highly efficient in enhanced oil recovery (EOR). The performance is a function of preparation and modification processes. The use of SNP modified by (3–Aminopropyl) triethoxysilane (APTES) is yet to be extensively examined for potential use in EOR. In this study, a modified SNP was examined to determine its influence in EOR applications. Sessile drop technique was utilized to determine the effectiveness of the modified SNP in altering the wettability of the oil-wet sandstone core. Subsequently, the interfacial tension (IFT) between oil and water was also investigated. Furthermore, the oil displacement efficiency of the modified nanofluid was compared with the unmodified. Zeta potential (ζ–potential), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscope (FESEM), and energy dispersive X–ray (EDX) spectra were used to confirm the modification of the SNP. The results show that APTES adhered to the surface of the modified SNP, and the particles are finely dispersed and stable in aqueous solution. The ζ–potential indicates that the surface charge of the particles increased from −16 mV to +26.4 mV after modification, which indicates long term stability when used in EOR processes. The silica nanofluids (SNFs) altered the wettability of sandstone core from oil–wet at a contact angle of 134.7° to water–wet at a contact angle of 54.3° (modified SNF) and 54.5° (unmodified SNF), at low concentrations. Also, the IFT of the modified SNF was low compared to unmodified SNF and APTES. The oil recovery of water flooding showed 62.9% and it improved to 75% and 69.6% when modified and unmodified SNFs were used, respectively. The pressure drop of the modified SNF was higher compared to the unmodified SNF which confirmed the stability of the modified SNF. Thus, the SNFs were very efficient in mobilizing trapped oil at ambient conditions and is, therefore, recommended for EOR processes