Control of Asphaltene Precipitation by MgO and NiO Nanoparticles as Inhibitors onto Calcite Surface: Experimental Approach

Asphaltene precipitation and deposition in carbonate petroleum reservoirs is a major flow assurance issue. Asphaltene structure consists of hydrocarbons and various heteroatoms (e.g., O, N, S). These active functional groups in asphaltene structure are the main reason for asphaltene adsorption onto rock's surface. Development of effective asphaltene precipitation requires a deep understanding of the interaction of asphaltene and reservoir rock surface. Nano-inhibitors are a proper candidate for asphaltene precipitation inhibitors owing to their small size (<100 nm) and stability in porous media. Nanoparticles adsorb the asphaltene in the oil medium decreasing the rate of asphaltene accumulation and consequently precipitation of asphaltene onto surface. The type of nanoparticles, surface area, chemistry, and thermodynamic conditions are the main parameters affecting the amount of asphaltene adsorption onto nanoparticle surfaces. Hence, it is necessary to select suitable nanoparticles considering the nature of asphaltene and thermodynamic conditions. This research work is an attempt to fill a research gap in the literature on the amount of asphaltene adsorption on calcite as the main reservoir rock surface in carbonates in presence of nanoparticles. The main aims of the present research work include assessing the performance of MgO and NiO nanoparticles on preventing asphaltene precipitation onto calcite surfaces using sophisticated analytical tools including X-ray photoelectron microscopy (XPS)-NEXSA and atomic force microscopy (AFM). The AFM and contact angle measurements confirm that the MgO and NiO nanoparticles can reduce the amount of asphaltene precipitation under non-equilibrium conditions by adsorbing asphaltene in the medium.