Structural Transformation of Clay Minerals by a New Molecular Dynamics Simulation Method

2010 ◽  
Author(s):  
Jianfeng Wang ◽  
Marte Gutierrez ◽  
Jane W. Z. Lu ◽  
Andrew Y. T. Leung ◽  
Vai Pan Iu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Clay Minerals ◽  
Structural Transformation ◽  
Simulation Method ◽  
Dynamics Simulation ◽  
Transformation Of Clay Minerals

scholarly journals Molecular Dynamics Simulation of Clay Hydration Inhibition of Deep Shale

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1069
Author(s):  
Yayun Zhang ◽  
Cong Xiao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Clay Minerals ◽  
Oil And Gas ◽  
Interlayer Spacing ◽  
Simulation Method ◽  
Stability Control ◽  
Wellbore Stability ◽  
Dynamics Simulation ◽  
Charge Balance

In the process of the exploitation of deep oil and gas resources, shale wellbore stability control faces great challenges under complex temperature and pressure conditions. It is difficult to reflect the micro mechanism and process of the action of inorganic salt on shale hydration with the traditional experimental evaluation technology on the macro effect of restraining shale hydration. Aiming at the characteristics of clay minerals of deep shale, the molecular dynamics models of four typical cations (K+, NH4+, Cs+ and Ca2+) inhibiting the hydration of clay minerals have been established by the use of the molecular dynamics simulation method. Moreover, the micro dynamics mechanism of typical inorganic cations inhibiting the hydration of clay minerals has been systematically evaluated, as has the law of cation hydration inhibition performance in response to temperature, pressure and ion type. The research indicates that the cations can promote the contraction of interlayer spacing, compress fluid intrusion channels, reduce the intrusion ability of water molecules, increase the negative charge balance ability and reduce the interlayer electrostatic repulsion force. With the increase in temperature, the inhibition of the cations on montmorillonite hydration is weakened, while the effect of pressure is opposite. Through the molecular dynamics simulation under different temperatures and pressures, we can systematically understand the microcosmic dynamics mechanism of restraining the hydration of clay in deep shale and provide theoretical guidance for the microcosmic control of clay hydration.

scholarly journals Molecular Structural Transformation of 2:1 Clay Minerals by a Constant-Pressure Molecular Dynamics Simulation Method

2010 ◽  
Vol 2010 ◽  
pp. 1-13
Author(s):  
Jianfeng Wang ◽  
Marte S. Gutierrez
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Cell Size ◽  
Clay Minerals ◽  
Structural Transformation ◽  
Constant Pressure ◽  
Shape Change ◽  
Interlayer Spacing ◽  
Dynamics Simulation ◽  
Size And Shape

This paper presents results of a molecular dynamics simulation study of dehydrated 2:1 clay minerals using the Parrinello-Rahman constant-pressure molecular dynamics method. The method is capable of simulating a system under the most general applied stress conditions by considering the changes of MD cell size and shape. Given the advantage of the method, it is the major goal of the paper to investigate the influence of imposed cell boundary conditions on the molecular structural transformation of 2:1 clay minerals under different normal pressures. Simulation results show that the degrees of freedom of the simulation cell (i.e., whether the cell size or shape change is allowed) determines the final equilibrated crystal structure of clay minerals. Both the MD method and the static method have successfully revealed unforeseen structural transformations of clay minerals upon relaxation under different normal pressures. It is found that large shear distortions of clay minerals occur when full allowance is given to the cell size and shape change. A complete elimination of the interlayer spacing is observed in a static simulation. However, when only the cell size change is allowed, interlayer spacing is retained, but large internal shear stresses also exist.

Femtosecond photoelectron spectroscopy of the I2− anion: A semiclassical molecular dynamics simulation method

1999 ◽  
Vol 110 (8) ◽  
pp. 3736-3747 ◽  
Author(s):  
Victor S. Batista ◽  
Martin T. Zanni ◽  
B. Jefferys Greenblatt ◽  
Daniel M. Neumark ◽  
William H. Miller
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Photoelectron Spectroscopy ◽  
Simulation Method ◽  
Dynamics Simulation

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.

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