Role of sodium dodecyl sulfate surfactant at the Interface of the Decane + Brine in the Presence of CO2, CH4, and Their Mixture

Abstract
Role of Sodium Dodecyl Sulfate Surfactant at the Interface of the Decane + Brine System in the Presence of CO2, CH4, and Their Mixture/nNilesh Choudhary1,2, Arun Kumar Narayanan Nair2, Shuyu Sun2/n1. Indian Institute of Technology Tirupati, Tirupati, India, and 2. King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia/nIntroduction /nThe emission of anthropogenic CO2 is one of the major causes of global climatic changes. Carbon capture and storage technology might be beneficial for mitigating these emissions. Various adsorbents (e.g., carbon nanotubes and clays) have been extensively utilized for carbon dioxide capture. In enhanced oil recovery (EOR) operations, the oil recovery could also be combined with carbon dioxide storage. The water-alternating-gas (WAG) approach has been utilized for mobility control during CO2 -EOR operations. The WAG cycles consist of injecting water (or surfactant) and CO2 alternatively into the reservoirs. Lowering the interfacial tension (IFT) of the oil + water system leads to an increase in the capillary number which may help to recover more oil. In general, the presence of surfactant/CO2 decreased this IFT. In addition, the captured CO2 contains impurities (e.g., CH4) that may have an important influence on the EOR operations./nSimulation Method/nMD simulations of Decane + water + surfactant and Decane + brine + surfactant two-phase systems in the presence of CH4 and CO2 at 323 and 443 K, and pressure up to 100 MPa were carried out using the GROMACS package. The salt (NaCl) concentration is 2.7 mol/kg and the amounts of surfactant adsorbed at the interface are 0.008 and 0.016 SDS/Å2. Each system was equilibrated for 5 ns in the NPT ensemble (only Lz varied) and we ran a 5 ns production under NVE conditions./nConclusions/n•The addition of CH4, CO2, and the presence of SDS surfactant at the interface reduced the IFTs of the Decane + water and Decane + brine (NaCl) systems./n•The effect of CO2 is more because the interface was highly enriched with CO2 molecules than with CH4 molecules./n•The interfacial thickness between water and Decane/CH4/CO2 molecules increases with increasing surfactant concentration and decreases with salt./nReferences/n1.Choudhary, N., Nair, A. K. N., & Sun, S. (2021). Interfacial Behavior of the Decane + Brine + Surfactant System in the Presence of Carbon Dioxide, Methane, and Their Mixture. Soft Matter (accepted) https://doi.org/10.1039/D1SM01267C/n2.Choudhary, N., Nair, A. K. N., Ruslan, M. F. A. C., & Sun, S. (2019). Bulk and interfacial properties of Decane in the presence of carbon dioxide, methane, and their mixture. Scientific reports, 9(1), 1-10. https://doi.org/10.1038/s41598-019-56378-y/n3.Choudhary, N., Ruslan, M. F. A. C., Nair, A. K. N., & Sun, S. (2021). Bulk and interfacial properties of alkanes in the presence of carbon dioxide, methane, and their mixture. Ind. Eng. Chem. Res., 60(1), 729-738. https://doi.org/10.1021/acs.iecr.0c04843/n4.Choudhary, N., Ruslan, M. F. A. C., Nair, A. K. N., Qiao, R., & Sun, S. (2021). Bulk and Interfacial Properties of the Decane+ Brine System in the Presence of Carbon Dioxide, Methane, and Their Mixture. Ind. Eng. Chem. Res., 60(30), 11525-11534. https://doi.org/10.1021/acs.iecr.1c01607/nAcknowledgment/nWe thank the support of this work by the KAUST under Award No. OSR-2019-CRG8-4074 and HPC:-SHAHEEN/IBEX/n

Conference/Event Name
KAUST Workshop on Porous Media & 1st InterPore Saudi Chapter Annual Meeting 2021

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