Estudo do efeito da adição de gás condensado sobre o ponto de fluidez e a viscosidade de petróleos pesados

Abstract

In this work it was studied the behavior of four heavy oils with API densities varying from 13.7 to 21.6, under the effect of gas condensate addition, with the objective of obtaining relevant information about these oils flowing process. So, it was analyzed the behavior of density at 20 °C, maximum and minimum pour points, and dynamic viscosity at 50 °C of oils containing different concentrations of gas condensate. It was also analyzed the effect of the temperature variation over the viscosities of the crude oils and additionally, after the study of the gas condensate effect over the oils, it was evaluated the behavior of the dynamic viscosities of them with the addition of different organic solvents (kerosene, turpentine and toluene). The results indicated that gas condensate was efficient to reduce the density, the maximum and minimum pour points and the viscosity of the four heavy oils analyzed. Oil A presented a decaying rate lower than the other oils and it was the one which presented the nearest behavior of ideal mixture. The heaviest oil sample (oil D) was the one which presented the highest variations in the maximum and minimum pour points values with the condensate addition, reaching a total reducing of 19 °C in the maximum pour point and the total of 21 °C in the minimum pour point with the addition of only 10,7% v/v of gas condensate. In the results obtained by the dynamic viscosity analysis it was observed the great majority of the prepared mixtures presented a Newtonian fluid behavior. All samples presented a notable decrease on their viscosities, reaching percent values which varied between 75 and 91%, in the concentration of 14% v/v of gas condensate. From this concentration the viscosity kept reducing but in a more attenuated way, and the condensate use over this concentration may mean unnecessary costs with the solvent with the objective of reducing the heavy oils viscosity. Oil D was the one which presented the highest values of viscosity reduction while oil B presented the lowest values. Comparing gas condensate with the other three organic solvents tested, condensate presented a very similar behavior to toluene when analyzed their viscosity reduction capacities of the studied oils.