Molecular insight into the oil extraction and transport in CO2 flooding with reservoir depressurization. (February 2020)

• Record Type: Journal Article
• Authors: Fang, Timing; Zhang, Yingnan; Yan, Youguo; Wang, Zhiyuan; Zhang, Jun
• Is Part Of: International journal of heat and mass transfer. Volume 148(2020)
• Publication Date: 2020-02
• Subjects: Molecular dynamics simulation -- Carbon dioxide -- Depressurization -- Tight oil; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2019.119051
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Dynamic extraction with different depressurization rates was studied. Continuous extraction was beneficial from the interaction energy decays. Oil extraction in non-equilibrium states was more sensitive to temperature. Shrinkage of miscible zone hindered the migration of oil molecules. Abstract: In this study, the mechanism of CO2 extracting hydrocarbon with reservoir depressurization was investigated through molecular dynamic simulations. First, the effects of different depressurization rates (ΔP/0.1, 0.5, 1.0 and 2.0 ns) on the extraction results were explored to ascertain the most efficient rate. Subsequently, the depressurizing rate with ΔP/1.0 ns was taken to characterize the extraction process, and then the association between the energy release of the system and the phase separation was verified to be vital to improve tight oil recovery. Next, an Arrhenius relationship between the number of extracted C10 and temperature before and after depressurization was found, and the activation energies were exploited to predict the production, suggesting that the effect of temperature on the extraction results is more significant when the system is in a non-equilibrium state. This simulation study provides microscopic insights into the implication of depressurization. Graphical abstract: Image, graphical abstract