scholarly journals Oil Occurrence States in Shale Mixed Inorganic Matter Nanopores

2022 ◽  
Vol 9 ◽  
Author(s):  
Shuang Liang ◽  
Jia-Ming Wang ◽  
Yi-Kun Liu ◽  
Bo Liu ◽  
Shuo Sun ◽  
...  
Keyword(s):  
Pore Size ◽  
Solid Wall ◽  
Mass Density ◽  
Dynamics Simulation ◽  
Shale Oil ◽  
Oil Composition ◽  
Theoretical Support ◽  
Inorganic Matter ◽  
Shale Composition ◽  
Selection Of

In present paper, the mineral and fluid compositions of shale oil from the Songliao Basin are analyzed systematically using core samples, X-ray diffractometer (XRD), and gas chromatography (GC). The effects of shale mineral composition, pore size, temperature, and pressure on the mass density of the adsorbed layers are then studied utilizing molecular dynamics simulation. The results show that illite and quartz are predominant in the micro petrological components of the shale, and nC19 is the main carbon peak. The fluid consists primarily of n-alkane molecules, and nC19 is found to be representative of the shale oil composition. Moreover, the adsorbing effect of quartz-illite mixed wall is between that of a pure mineral wall (illite and quartz), indicating that the selection of a mixed wall is similar to the actual shale composition. If the pores are inorganic, the minimum pore size of only adsorption oil is smaller than the organic pores. The critical adsorption point of shale oil in inorganic pores is less than 3.2 nm. Furthermore, compared to pressure, the temperature has a more significant effect on fluid adsorption due to the correlation with the kinetic energy of alkane molecules. This research shows the oil occurrence status in inorganic matter nanopore with a mixed solid wall, and provides theoretical support for shale oil exploration.

scholarly journals A predictable smoothing evolution model for computer-controlled polishing

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Jing Hou ◽  
Pengli Lei ◽  
Shiwei Liu ◽  
Xianhua Chen ◽  
Jian Wang ◽  
...  
Keyword(s):  
Evolution Model ◽  
Quantitative Prediction ◽  
Theoretical Support ◽  
Model Combining ◽  
Process Guidance ◽  
Dependent Model ◽  
Computer Controlled Optical Surfacing ◽  
Computer Controlled ◽  
Time Dependent Model ◽  
Selection Of

AbstractQuantitative prediction of the smoothing of mid-spatial frequency errors (MSFE) is urgently needed to realize process guidance for computer controlled optical surfacing (CCOS) rather than a qualitative analysis of the processing results. Consequently, a predictable time-dependent model combining process parameters and an error decreasing factor (EDF) were presented in this paper. The basic smoothing theory, solution method and modification of this model were expounded separately and verified by experiments. The experimental results show that the theoretical predicted curve agrees well with the actual smoothing effect. The smoothing evolution model provides certain theoretical support and guidance for the quantitative prediction and parameter selection of the smoothing of MSFE.

scholarly journals Pore-Scale Simulation of Confined Phase Behavior with Pore Size Distribution and Its Effects on Shale Oil Production

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1315
Author(s):  
Jingwei Huang ◽  
Hongsheng Wang
Keyword(s):  
Phase Equilibrium ◽  
Equation Of State ◽  
Pore Size Distribution ◽  
Phase Behavior ◽  
Pore Size ◽  
Size Distribution ◽  
Critical Role ◽  
Shale Oil ◽  
Pore Scale ◽  
Modified Equation

Confined phase behavior plays a critical role in predicting production from shale reservoirs. In this work, a pseudo-potential lattice Boltzmann method is applied to directly model the phase equilibrium of fluids in nanopores. First, vapor-liquid equilibrium is simulated by capturing the sudden jump on simulated adsorption isotherms in a capillary tube. In addition, effect of pore size distribution on phase equilibrium is evaluated by using a bundle of capillary tubes of various sizes. Simulated coexistence curves indicate that an effective pore size can be used to account for the effects of pore size distribution on confined phase behavior. With simulated coexistence curves from pore-scale simulation, a modified equation of state is built and applied to model the thermodynamic phase diagram of shale oil. Shifted critical properties and suppressed bubble points are observed when effects of confinement is considered. The compositional simulation shows that both predicted oil and gas production will be higher if the modified equation of state is implemented. Results are compared with those using methods of capillary pressure and critical shift.

scholarly journals The therapeutic mechanism of epilepsy seizures in different target areas: Research on a theoretical model

2021 ◽  
Vol 29 ◽  
pp. 455-461
Author(s):  
Bing Hu ◽  
Zhizhi Wang ◽  
Minbo Xu ◽  
Luyao Zhu ◽  
Dingjiang Wang
Keyword(s):  
Pyramidal Neurons ◽  
Control Mechanism ◽  
Difficult Problem ◽  
Calculation Model ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Theoretical Support ◽  
Therapeutic Mechanism ◽  
Optimal Target ◽  
Selection Of

BACKGROUND: The selection of optimal target areas in the surgical treatment of epilepsy is always a difficult problem in medicine. OBJECTIVE: We employed a theoretical calculation model to explore the control mechanism of seizures by an external voltage stimulus acting in different nerve nuclei. METHODS: Theoretical analysis and numerical simulation were combined. RESULTS: The globus pallidus, excitatory pyramidal neurons, striatal D1 neurons, thalamic reticular nucleus and specific relay nuclei were selected, we analyzed that the electrical stimulation has different effects in these target areas. CONCLUSIONS: The data selected were reasonable in study, the results may give a theoretical support for similar studies in clinical.

Molecular Dynamics Simulation Study of Lecithin Inhibiting Hydrate-Dissociation

2017 ◽  
Vol 890 ◽  
pp. 252-259
Author(s):  
Le Wang ◽  
Guan Cheng Jiang ◽  
Xin Lin ◽  
Xian Min Zhang ◽  
Qi Hui Jiang
Keyword(s):  
Molecular Dynamics ◽  
Water Movement ◽  
Simulation Analysis ◽  
Mass Density ◽  
Dynamics Simulation ◽  
Dissociation Process ◽  
Hydrate Dissociation ◽  
Hydrocarbon Chains ◽  
Dynamics Simulations ◽  
Mass Density Profile

Molecular dynamics simulations are used to study the dissociation inhibiting mechanism of lecithin for structure I hydrates. Adsorption characteristics of lecithin and PVP (poly (N-vinylpyrrolidine)) on the hydrate surfaces were performed in the NVT ensemble at temperatures of 277K and the hydrate dissociation process were simulated in the NPT ensemble at same temperature. The results show that hydrate surfaces with lecithin is more stable than the ones with PVP for the lower potential energy. The conformation of lecithin changes constantly after the balanced state is reached while the PVP molecular dose not. Lecithin molecule has interaction with lecithin nearby and hydrocarbon-chains of lecithin molecules will form a network to prevent the diffusion of water and methane molecules, which will narrow the available space for hydrate methane and water movement. Compared with PVP-hydrate simulation, analysis results (snapshots and mass density profile) of the dissociation simulations show that lecithin-hydrate dissociates more slowly.

A Molecular Dynamics Study on Effects of Nanostructural Clearances at an Interface on Thermal Resistance

2008 ◽  
Author(s):  
Masahiko Shibahara ◽  
Kosuke Inoue ◽  
Kiyomori Kobayashi
Keyword(s):  
Molecular Dynamics ◽  
Temperature Gradient ◽  
Thermal Resistance ◽  
Solid Wall ◽  
Middle Layer ◽  
Dynamics Simulation ◽  
Nanometer Scale ◽  
Liquid Density ◽  
Solid Interface ◽  
Solid Walls

The classical molecular dynamics simulation was conducted in order to clarify the effects of structural clearances in nanometer scale on thermal resistance at a liquid-solid interface. A liquid molecular region confined between the solid walls, of which the interparticle potential was Lennard-Jones type, was employed as a calculation system. The solid walls consisted of three atomic layers where the temperature of the middle layer was controlled by the Langevin method. Heat flux in the system was calculated numerically by integrating the forces that acted on the temperature controlled atoms by the Langevin method. The temperature jump between the solid wall and the liquid molecular region was calculated numerically. The thermal resistance at a liquid-solid interface was calculated numerically with changing the surface structural clearances in nanometer scale. Temperature gradient and liquid density were also changed as calculation parameters. With changing the surface structural clearances from 0nm to 2.5nm the thermal resistance at the interface once decreased and became the minimum value when the structural clearances were between 0.6 to 1.0 nm. The thermal resistance between the solid and the liquid increased when the structural clearances were more than 1.0nm. With the increase of the liquid density the thermal resistance between the solid and the liquid substantially decreased regardless of the temperature gradient and the surface structures in nanometer scale.

Multiscale flow characteristics of droplet spreading with microgravity conditions

2019 ◽  
Vol 97 (8) ◽  
pp. 869-874
Author(s):  
Xue-Qing Chen ◽  
Lei Tong
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Solid Wall ◽  
Gold Surface ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Contact Radius ◽  
Droplet Spreading ◽  
Fast Spreading ◽  
Slow Spreading

In this paper, mesoscopic lattice–Boltzmann method (LBM) and microscopic molecular dynamics simulation method were used to simulate droplet dynamic wetting under microgravity. In terms of LBM, the wetting process of a droplet on a solid wall surface was simulated by introducing the fluid–fluid and solid–fluid interactions. In terms of molecular dynamics simulation, the spreading process of water on gold surface was simulated. Calculation results showed that two kinds of calculation methods were based on the microscopic molecular theory or mesoscopic kinetics theory, and such models could effectively overcome the contact line paradox issue, which results from the macro-continuum assumption and non-slip boundary condition assumption. The spreading exhibits two-stage behavior: fast spreading and slow spreading stages. For the two simulation methods, the ratio of fast spreading stage duration to slow spreading duration, spreading capacity (equilibrium contact radius/initial radius), and the spreading exponent of the rapid stage were very close. However, the predictive spreading index of the slow spreading stage was different, owing to the different spreading mechanisms between meso- and nanoscales.

scholarly journals Mineral compositional controls on the porosity of black shales from the Wufeng and Longmaxi Formations (Southern Sichuan Basin and its surroundings) and insights into shale diagenesis

2018 ◽  
Vol 36 (4) ◽  
pp. 665-685
Author(s):  
Mei Han ◽  
Chao Han ◽  
Zuozhen Han ◽  
Zhigang Song ◽  
Wenjian Zhong ◽  
...  
Keyword(s):  
Organic Matter ◽  
Pore Size ◽  
Pore Volume ◽  
Total Pore Volume ◽  
Black Shales ◽  
Carbonate Content ◽  
Pore Sizes ◽  
Pore Size Distributions ◽  
Shale Composition ◽  
The Relationship

The effects of brittle minerals in shale diagenesis on shale pores remain controversial and it is difficult to quantify directly. However, the relationship between brittle minerals and shale pores could provide indirect guidance regarding diagenesis processes in post-mature marine shales. In this study, the pore size distribution was determined, and the relationship between pore volume and shale composition was examined in shale samples with different total organic carbon contents from the Wufeng and Longmaxi Formations, with the objective of distinguishing pore size ranges in organic matter and inorganic minerals, respectively, and studying shale diagenesis. The samples of the Wufeng and Longmaxi shales are composed of clay minerals, calcite, dolomite, quartz, feldspar, and some minor components. The pore size distributions, which were determined using nitrogen adsorption isotherm analysis of shale and kerogen, show similar trends for pore sizes less than approx. 6.5 nm but different trends for larger pore sizes. Mercury injection saturation shows that macropores account for 14.4–22% of the total pore volume. Based on a series of crossplots describing the relationships between shale composition and pore volume or porosity associated with different pore sizes as well as on scanning electron microscopy observations, organic matter pores were found to comprise most of the micro-mesopores (pore diameters < 6.5 nm). Organic matter pores and intraparticle pores associated with carbonate constitute the majority of mesopores (pore diameters 6.5–50 nm). Finally, interparticle pores associated with quartz comprise the majority of the macropores. The mesopores associated with carbonate were formed by dissolution during diagenesis, whereas the macropores associated with quartz are the remainders of the original interparticle pores. Mesopore volumes increase with increasing carbonate content while macropore volumes decrease due to the ‘pore size controlled solubility’ effect, which causes dissolved calcium carbonate to precipitate in larger macropores.

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