Influence of salinity and electrostatic fields on CO_(2) hydrate formation and the interfacial quasi-liquid layer in clay nanoconfinement:A molecular dynamics studyOA
Marine clay reservoirs are considered ideal substrates for hydrate-based CO_(2) capture and storage owing to their large specific surface area,high porosity and favorable adsorption capacity.Understanding the evolution mechanism of quasi-liquid layers(QLLs)and hydrate formation at clay interfaces under nanoconfinement is crucial for evaluating the spatial potential of storage matrices and enhancing CO_(2) sequestration efficiency.In this study,molecular dynamics(MD)simulations were conducted at 250 K and300 bar with a time step of 2 fs to investigate the effects of salinity and electrostatic fields on CO_(2) hydrate formation and QLL thickness within montmorillonite(MMT)slit pores.Simulation results indicate that CO_(2) hydrate nucleation and growth predominantly occur away from MMT interfaces,with elevated salinity significantly delaying nucleation onset.Dynamic salt exclusion during hydrate formation inhibits interfacial hydrate growth toward clay surfaces.Elevated salinity increases QLL thickness from 1.2 nm to 1.6 nm near isomorphic substitution surfaces and from 1.1 nm to 1.4 nm near non-substituted MMT surfaces.Notably,under seawater salinity conditions,QLL thickening demonstrates dynamic coupling with salt exclusion effects.Electrostatic fields substantially influence nucleation stochasticity and spatial distribution through electric double-layer restructuring and ion migration.QLL thickness near isomorphic substitution surfaces shows limited sensitivity to electrostatic fields,stabilizing at about 1.15 nm.Conversely,QLLs adjacent to non-substituted surfaces exhibit significant field dependence due to surface ion redistribution,with thickness increasing to 1.55 nm at an applied field of 0.3 V/nm before reaching a plateau.These molecular-scale insights into salinity and electrostatic effects on hydrate formation and interfacial QLL evolution provide critical references for optimizing clay-based carbon storage matrices and advancing CO_(2) sequestration technologies.
Jie Chen;Jia-fang Xu;Zheng-cai Zhang;Ling-feng Kong;Cheng-dong Yuan;Anastasia Ivanova;Abdolreza Farhadian;Ya-hua Wang;Yuan-hang Zhang;Li-yuan Zhang;Gao-wei Hu
School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China Department of Geology,M.V.Lomonosov Moscow State University,Moscow 119991,RussiaSchool of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China State Key Laboratory of Deep Oil and Gas,Qingdao 266580,ChinaLaboratory for Marine Mineral Resources,Laoshan Laboratory,Qingdao 266237,ChinaSchool of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China China National Oil and Gas Exploration and Development Corporation,Beijing 100034,ChinaCenter for Petroleum Science and Engineering,Skolkovo Institute of Science and Technology,Moscow 121205,RussiaCenter for Petroleum Science and Engineering,Skolkovo Institute of Science and Technology,Moscow 121205,RussiaDepartment of Petroleum Engineering,Kazan Federal University,Kazan 420008,RussiaSchool of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China Department of Geology,M.V.Lomonosov Moscow State University,Moscow 119991,RussiaSchool of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China Department of Geology,M.V.Lomonosov Moscow State University,Moscow 119991,RussiaCenter for Petroleum Science and Engineering,Skolkovo Institute of Science and Technology,Moscow 121205,Russia Department of Geology,M.V.Lomonosov Moscow State University,Moscow 119991,RussiaThe Key Laboratory of Gas Hydrate,Ministry of Natural Resources,Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266237,China
能源科技
CO_(2) hydrateCombustible iceClay nanoconfinementQuasi‑liquid layerSalinityElectrostatic fieldsMolecular dynamics simulationCarbon sequestrationCarbon neutralityCarbon capture,utilization,and storage(CCUS)
《China Geology》 2026 (3)
P.596-610,15
the support provided by the Shandong Provincial Key Laboratory of Oilfield Chemistryfinancially supported by the Laoshan Laboratory(LSKJ2202203503)National Natural Science Foundation of China(42176212,51874343 and 42276229)Fundamental Research Funds for the Central Universities(24CX02013A)Natural Science Foundation of Shandong Province of China(ZR2019BD051)。
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