A Technological Nanofluid for Washing Off Oil Deposits and Increasing Oil Recovery

Abstract

The productivity of wells in the late stage of oil production is directly related to oil deposits, which gradually form blockages, fill the pipeline, and interfere with the free movement of the flow of produced oil. Based on chemical composition, oil deposits are difficult to remove and require the selection of process fluids. An extractive method is proposed for the removal of oil deposits with the participation of process fluids, including nanofluids. The proposed nanofluid was prepared on the basis of low-viscosity petroleum oil with the addition of an organic solvent, a mixture of various classes of surface-active substances (surfactants), and alkali metal salts. The nanofluid contains a nanosolution based on alkali metal salts, with concentrations of Na3PO4=13700ppm, KCl=950ppm, and CaCl2=241ppm, which were determined by the readings of an ICPE-9820 spectrometer. It was found that the tested process fluid reduces the viscosity of deposits and interfacial tension and leads to an increase in fluid movement in the pipeline. The experiments were carried out in the direction of reducing the interfacial tension at the interface with the solvent. It was shown that the process of sediment reduction depends on the composition of the ARPD, the surfactant, the composition of the solvent, and the salinity of the nanosolution. It is advisable to flush oil deposits from the surface of the tubing using the process fluid when creating a circular circulation in a closed annular space - tubing – annulus circuit.