The article presents the results of the analysis of asphalt-resin-paraffin deposits (ARPD) formed during the interaction of oil and acid compositions using IR Fourier-transform spectroscopy. Oil samples from three wells were mixed with acid compositions of different concentration. The studies were carried out using an IRAffinity-1S IR Fourier spectrometer with a spectral range on a wave number scale from 7800 to 350 cm-1. The spectral resolution was no less than 0.5 cm-1. Limits of permissible absolute measurement error were ±1.5 cm-1. Spectra of optical density of studied oil control sample and mixtures of oil with acid compositions in the range of 700-1700 cm-1 were obtained. Based on these data, the indexes of aliphaticity, branching and aromaticity were calculated. It has been established that aliphaticity index and branching index increase as the compositions react, and the aromaticity index decreases. This indexes change indicates a significant decrease in the asphaltenes content (their precipitation in the acid emulsion). The results obtained were confirmed by filtration of acidic compounds through a metal sieve. It has been shown that spectral coefficients calculated on the basis of the IR spectra of oil make it possible to describe its group chemical composition and provide additional information on a structure of aliphatic part of oil hydrocarbons when interacting with acidic compositions. The authors concluded that implementation of the considered research method will make it possible to prevent complications caused by the formation of emulsions that are poorly filtered in the oil-saturated formation, and bottomhole zone clogging by ARPD formed during acid composition and oil interaction.
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