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Quantifying the Possible Risks of Asphaltene Precipitation during Different Gas-Based EOR Scenarios (CO2, N2, And CH4 In
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
In this work, PC-SAFT equation of state has been used to model the phase behavior of asphaltene in crude oil under pressure depletion and gas injection. The effects of N2, CO2, and dry gas injection into one of Iranian crudes, on asphaltene precipitation has been investigated. Complete PVT tests, SARA analysis, and Light-scattering technique (LST) using near-infrared (NIR) light system were performed on the crude oil to find the composition, molecular weight, SARA fraction, PVT data, and onset pressure of asphaltene fluctuation. Multi-phase flash calculation (V-L, L-L, and V-L-L) is performed to compute the phase fraction and the distribution of the components in each phase at a given pressure, temperature, feed composition, and injected gas composition. The quasi-Newton successive-substitution (QNSS) method is applied to perform the phase stability analysis to predict the number of phases at the given condition using the stationary point criterion.
The results indicate that the instability occurs in a wider range of pressure during N2 injection and addition of N2 and CH4 into the studied crude oil dramatically increases the instability of asphaltene. While, CO2 can act as an inhibitor of asphaltene precipitation at the reservoir temperature; this behaviour is explained through the solubility parameter concept.