Perpustakaan Digital ITB

The calcite mineral is frequently present in sandstone and is a cementing agent for them. Calcite (CaCO3) is a clastic mineral derived from the carbonate structure in rock mineralogy, which forms in shallow oceans and originates from shelled creatures. Calcite influences oil recovery by altering the rock's wettability, affecting oil extraction. In the chemical-enhanced oil recovery (EOR) method, surfactant injection is an alternative to augment oil recovery by altering rock wettability to more water-wet by reducing interfacial tension. Recent studies indicate that nanoparticles significantly improve oil recovery, yet more research is needed to examine the mechanisms by which surfactants and nanomaterials modify the wettability of rocks. This study examines the impact of calcite mineral composition in rocks and TiO2 nanomaterials on surfactant solution performance. This study used variations of calcite minerals with concentrations of 5 wt.%, 10 wt.%, and 15 wt.% and TiO2 nanomaterials with various concentrations of 100 ppm, 250 ppm, and 500 ppm. Laboratory tests conducted in this study included pH measurements, conductivity, contact angle, zeta potential, and atomic absorption spectrometry (AAS). In terms of the pH and conductivity of the solution, the results showed that adding nanomaterials to the surfactant solution made the solution more alkaline and increased its electrochemistry. Based on the contact angle test, it was found that the high concentration of calcite minerals resulted in neutral rock wetness conditions; in the solution, the addition of nanomaterials had a significant impact on changing the rock wetness to be more water-wet. Based on the zeta potential test, the presence of calcite minerals affects the acid-base properties of rocks, which will later impact the release of oil from them. The pH results of the rocks show that the addition of calcite minerals impacts the adsorption mechanism and ion interaction of the nanomaterial surfactant solution used. Atomic absorption spectrometry testing of rocks shows that the solubility of Ca2+ in the core flooding effluent results is in line with the concentration level contained in the rocks; the highest presence of Ca2+ is at a calcite concentration of 15 wt.% and decreases as the calcite concentration decreases. Based on the results obtained from the measurements, it is concluded that the presence of calcite minerals in reservoir rocks has been proven to affect the wettability of rocks from less water-wet to neutral wet.