Recovery mechanisms of hydrocarbon mixtures in organic and inorganic nanopores during pressure drawdown and CO2 injection from molecular perspectives

Zhang, Mingshan; Zhan, Shiyuan; Jin, Zhehui

doi:10.1016/j.cej.2019.122808

Cited by 86 publications

(41 citation statements)

References 98 publications

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“…To date, much research efforts have been devoted to optimizing the two-phase displacement process, such as refining the external forces, [7][8][9] changing the composition of capillary surface, [10][11][12] and adjusting the properties of fluids 13 like viscosity and interfacial tension. Among others, adding extra chemicals (surfactant, polymer) can effectively adjust the property of injecting fluids, and meanwhile change the composition of capillary surface with their adsorption, which is thus efficient in regulating two-phase displacement process.…”

Section: Introductionmentioning

confidence: 99%

Insight into the pressure-induced displacement mechanism for selecting efficient nanofluids in various capillaries

Wang

Zhang

2020

Environ. Sci.: Nano

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Section: Introductionmentioning

confidence: 99%

Insight into the pressure-induced displacement mechanism for selecting efficient nanofluids in various capillaries

Wang

Zhang

2020

Environ. Sci.: Nano

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“…In this work, to weed out the effect of random roughness of the wall structure to the gas transport, a full atomic smooth structure of three graphite layers is used to represent the organic nanopores in shale reservoir (as shown in Figure 3). Such a simplified method is widely used in the MD simulations which are focused on the research of geofluids adsorption and flow performance in shale organic pores [15,[21][22][23]45]. The dimension of the graphene layers in x-and y-direction are L x = 20:27 nm and L y = 10:07 nm, respectively, and such a box size is enough to make the transport behavior of the gas molecules reach a steady state in the NEMD simulation.…”

Section: Molecular Models and Simulation Methodsmentioning

confidence: 99%

“…According to the value of pore diameter, d, the pores could be divided as micropore (d < 2 nm), mesopore (2 nm ≤ d ≤ 50 nm), and macropore (d > 50 nm) suggested by the International Union of Pure and Applied Chemistry (IUPAC) [1,2,12]. In one aspect, such amounts of nanopores provide large internal surface areas and result in great adsorption of shale gas; the adsorbed gas occupies a significant percentage of the gas-in-place in shale [13][14][15]. The bulk density and the viscosity cannot represent the physical properties actually since the distribution of the gas confined in nanopore may be inhomogeneous [16,17].…”

Section: Introductionmentioning

confidence: 99%

Effect of Surface Type on the Flow Characteristics in Shale Nanopores

Zhan

et al. 2021

Geofluids

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The underlying mechanism of shale gas migration behavior is of great importance to understanding the flow behavior and the prediction of shale gas flux. The slippage of the methane molecules on the surface is generally emphasized in nanopores in most predicted methods currently. In this work, we use molecular dynamic (MD) simulations to study the methane flow behavior in organic (graphene) and inorganic (quartz) nanopores with various pore size. It is observed that the slippage is obvious only on the graphene nanopores and disappeared on the quartz surface. Compared with the traditional Navier-Stokes equation combined with the no-slip boundary, the enhancement of the gas flux is nonnegligible in the graphene nanopores and could be neglected in the quartz nanopores. In addition, the flux contribution ratios of the adsorption layer, Knudsen layer, and the bulk gas are analyzed. In quartz nanopores, the contributions of the adsorption layer and the Knudsen layer are slight when the pore size is larger than 10 nm. It is also noted that even if the Knudsen number is the same, the flow mode may be various with the effect of the pore surface type. Our work should give molecular insights into gas migration mechanisms in organic and inorganic nanopores and provide important reference to the prediction of the gas flow in various types of shale nanopores.

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“…Clay minerals, such as illite, are common layered aluminosilicates that are widely distributed in soils and sediments, and they contain abundant nanopore structures that have great environmental significance (Dietel, Ufer, Kaufhold, & Dohrmann, 2019;Yesilbas, Holmboe, & Boily, 2019;Zhang, Zhan, & Jin, 2020). Limited space is an important contributor to the large specific surface area, high ion exchange capacity and good adsorption performance of clay.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of cations at the illite–water interface and its effect on intrinsic potassium ions

Xing

Tang

et al. 2021

European J Soil Science

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Na + , K + , Cs + and Ca 2+ are common exogenous cations that could be introduced into soils either via long-term tillage with inorganic fertilizers or the leakage of nuclear waste. However, the manner in which they co-adsorb and compete with the intrinsic potassium ions in illite, the response of intrinsic potassium (K 0+ ), as well as the underlying mechanisms of these interactions, remain unclear. These aspects were explored using molecular dynamics simulations based on a series of concentrations. Because of the competition between exogenous cations and K 0+ , the number of adsorbed exogenous cations such as Na + increased by 11.2, whereas the corresponding number of adsorbed potassium decreased by 14.2, with the increase in concentration from 0.1 to 1.0 molÁL À1 , indicating that long-term application of inorganic fertilizers tends to promote the release of intrinsic potassium. This was further validated from the increased adsorption free energy of IS (inner-sphere) K 0+ , which increased from À54.3 kJÁmol À1 (0.1 molÁL À1 ) to À42.9 kJÁmol À1 (1.0 molÁL À1 ). The stability of both exogenous cations and intrinsic potassium decreased with the increase in concentration. This was mainly caused by the reduction of illite-cation interactions, as evidenced by the radial distribution function analysis. Nonetheless, intrinsic potassium always dominated the competition, as its abundance was lower than that of exogenous cations only beyond 0.7 molÁL À1 . Different exogenous cations exerted diverse effects on the intrinsic potassium and may vary with the concentration, as reflected by the distribution, adsorption number, coordination environment and adsorption stability.Generally, the effect of exogenous cations on intrinsic potassium decreased as Ca 2+ > Na + > Cs + , which may have been caused by the different adsorption sites. These results provide new insight into the environmental effect of the excessive use of inorganic fertilizers and the leakage of radioactive waste in soils. Highlights• Increase in exogenous cations tended to promote the release of intrinsic potassium in illite.

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Recovery mechanisms of hydrocarbon mixtures in organic and inorganic nanopores during pressure drawdown and CO2 injection from molecular perspectives

Cited by 86 publications

References 98 publications

Insight into the pressure-induced displacement mechanism for selecting efficient nanofluids in various capillaries

Insight into the pressure-induced displacement mechanism for selecting efficient nanofluids in various capillaries

Effect of Surface Type on the Flow Characteristics in Shale Nanopores

Adsorption of cations at the illite–water interface and its effect on intrinsic potassium ions

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