Research of the effect of a new composition against asphaltene-resin-paraffin deposits

New multifunctional compositions were prepared from chemical reagents of various purposes under laboratory conditions, and their effect on the rheological parameters of a heavy oil sample – such as freezing temperature, yield shear stress, viscosity, and oil deposits – was investigated for the first time. For comparison, the impact of the depressant additives Difron-4201 and Difron-3970, applied individually and as compositions, on the rheological parameters of the heavy oil was also examined. During the experiments, compositions with provisional names: AH-1, AH-2, AH-3, AH-4, AH-5, were applied at concentrations of 200, 300, 400, 500, 600 g/t. Difron-4201 was tested at 200, 300, 400, 500, 600, and 700 g/t, while Difron-3970 was tested at 250, 350, 450, 550, 750 g/t. The freezing temperature of the oil sample was reduced from 22°C to 5, 1, –4, –3 and –7°C due to the influence of the specified concentrations of the individual reagents and compositions. The effect of the reagents against oil deposits was investigated using the “coldfinger test” method. During the process, the amount of asphaltene-resin-paraffin deposits accumulated on the surface after 30, 60, 90, 120, 180 and 240 minutes at tube temperatures of 0, 5, 10, 20, 30°C was determined. To evaluate the effect of the reagents, the amount of oil deposits formed during the specified time and at given temperature without reagents was also measured. Using a known mathematical dependence, the effect was calculated for each concentration of the individual reagents and compositions at 5°C in the “coldfinger test”. The highest effects were observed at concentrations of 700 g/t for Difron-4201, 750 g/t for Difron-3970, and 600 g/t for AH-1, AH-2, AH-3, AH-4, AH-5, with reduction rates of 75, 70, 78, 82, 87, 84 and 92%, respectively. The composition of oil deposits formed at each temperature over 240 minutes was also determined. The results showed that as the temperature increased, the amount of asphaltene and resin increased, while the paraffin content decreased. The values of rheological parameters K, n, τ0 of the oil sample, both with and without reagents, were determined according to Herschel-Bulkley model. Thus, as a result of numerous laboratory tests, the optimal reagent concentrations were found to be 700 g/t for Difron-4201, 750 g/t for Difron-3970 and 600 g/t for AH-series compositions. It was revealed that, compared to individual additives, the compositions were more effective, with the AH-5 composition showing the highest efficiency.