In the upstream asphaitene flow assurance community, both academics and industries are actively involved to predict the asphaitene deposit profile in wellbores and pipelines. Essential information for such a study is the amount of asphaltenes that can precipitate and, hence, deposit. In this work, the perturbed chain form of the statistical associating fluid theory (PC-SAFT) is applied to predict the asphaitene precipitation onset condition as well as the amount of precipitate under pressure depletion and high-pressure and high-temperature gas injection conditions- Previous PC-SAFT asphaitene studies in crude oil required the compositional data for both flashed gas and flashed liquid. This work shows a PC-SAFT crude oil characterization procedure when, only the composition of the monophasic reservoir fluid is available. After the model parameters for asphaitene onset pressure are estimated, the fitted parameters are used to predict the amount of asphaitene precipitation. The modeling results represent a good match for both upper and lower onset pressures. However, the precipitated asphaitene amount shows an overprediction by PC-SAFT with respect to experimental data obtained trom different techniques. The study in this paper discusses the accuracy of these experimental techniques at high-pressure and high-temperature conditions. It shows how a small experimental error during the measurement of precipitated asphaitene amount can result in a significant difference between modeled and experimental values. We invite discussion on the possibility of such errors and suggestions of experimental procedures or a new experimental tool for measuring the amount of precipitated asphaitene at high-pressure and high-temperature conditions.
展开▼
