Chemical study of asphaltene inhibitors effects on asphaltene precipitation of an Iranian oil field

The amount of precipitated asphaltene could be significantly reduced with pretreatment of asphaltene inhibitor, in the crude oil. Efficiency of asphaltene inhibitors mainly depends on some parameters, including pH of the oil and the chemical structure of asphaltene inhibitors. The amounts of asphaltene precipitation were experimentally measured using two n-paraffin precipitants, n-heptane and n-hexane. The performance of the studies on the asphaltene accumulation was evaluated using FTIR Spectroscopy analysis. The onset point was determined by three different commercial asphaltene inhibitors. The results showed that when an asphaltene inhibitor was not injected into the mixture of synthetic oil/n-heptane, asphaltene onset point (AOP) occurred at 35 vol% of n-heptane, while with addition of 3000 ppm of asphaltene B inhibitor, AOP occurred at 60 vol% of n-heptane. The inhibitors that have acidic and polar portions, play a role in the formation of resin as a result of the formation of bond with the polar regions of asphaltene, which reduced the asphaltene deposited in the crude oil due to the presence of normal paraffin. In addition to reducing the amount of asphaltene sedimentation, chemical inhibitors caused the AOP to be dropped. The experimental results showed that temperature condition is a key factor on the performance of different inhibitors on decreasing asphaltene precipitation.