The process of deposit formation in a sample of highly paraffinic crude oil, two samples of gas condensates and their mixtures is investigated. The amount of deposit in the oil is observed to increase with decreasing ambient temperature and hence it is significantly higher than the mass fraction of paraffins, asphaltenes, and resins due to the occlusion of liquid hydrocarbon in the crystal lattice cells. Using the method of gas-liquid chromatography, the individual compositions of n-alkanes responsible for the formation of deposits in the samples under study are determined. A monomodal distribution of n-alkanes in oil and gas condensate samples is observed. The deposits isolated fr om the crude oil and gas condensates are characterized by a bimodal molecular mass distribution of n-alkanes and an increased content of high molecular hydrocarbons. The efficiency of additives inhibiting the formation of deposits in the oil sample and its mixtures with condensates is investigated. The experimental K-210 additive is found to exhibit better inhibitor and depressor properties in the highly paraffinic crude oil. An addition of 0.05 % wt. of K-210 into the oil sample allowed reducing the deposition rate by 81-85 %. The inhibiting effect of K-210 however decreases in the oil - gas mixtures.
It is shown that the inhibitory effect of the additives based on poly (alkyl) acrylates depends on the composition of paraffin hydrocarbons and resin components of the oil systems under study. The stages of nucleating seed formation and spontaneous crystallization are determined from the cloud point, spontaneous crystallization temperature, and pour point. A possibility of adjusting the structural phase transition in the cases wh ere the temperature decreases during crystallite nucleation and growth is shown. The decrease in the spontaneous crystallization temperature upon introduction of 0.05% wt. of additives into the oil-gas mixture is negligible and is found to be about 3–5 °C, while the pour point of oil with an additive decreased by 13–17 °C and that of the oil-gas mixtures by 18–20 °C.
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