scholarly journals Study on Two Component Gas Transport in Nanopores for Enhanced Shale Gas Recovery by Using Carbon Dioxide Injection

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1101
Author(s):  
Chaohua Guo ◽  
Rongji Li ◽  
Xin Wang ◽  
Hongji Liu
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Shale Gas ◽  
Molecular Diffusion ◽  
Gas Transport ◽  
Transport Mechanisms ◽  
Apparent Permeability ◽  
Gas Concentration ◽  
Gas Recovery ◽  
Two Component

Injecting carbon dioxide to enhance shale gas recovery (CO2-EGR) is a useful technique that has raised great research interests. Clear understanding of the two-component gas transport mechanisms in shale nanopores is the foundation for the efficient development of shale gas reservoir (SGR) and also the long-term geological storage of CO2. Although extensive studies on single-component gas transport and corresponding models in shale nanopores have been carried out in recent years, limited studies have been conducted on two-component or even multi-component gas transport models in shale nanopores. In this work, the shale nanopores were classified into inorganic and organic nanopores. The corresponding models for two-component gas transport were constructed. Mechanisms including Knudsen diffusion, slip flow, viscous flow, and molecular diffusion are considered in the inorganic pores. In the organic pores, due to existence of adsorption gas, surface diffusion is further considered besides the aforementioned mechanisms. Effects of pressure, temperature, fraction of organic nanopores, and gas concentration were analyzed. Results show that gas apparent permeability is negatively correlated with pressure, and positively correlated with temperature and organic nanopore fraction. As the concentration of CH4 decreases, the apparent permeability of CH4 increases continuously, while the apparent permeability of CO2 decreases. The permeability ratio of CH4 in the total permeability is negatively correlated with pressure and gas concentration ratio. Additionally, the contribution of transport mechanisms to the total gas apparent permeability has been analyzed. It is found that the surface diffusion contributes up to 5.68% to gas apparent permeability under high pressure. The contribution of molecular diffusion can reach up to 88.83% in mesopores under low pressure. Under high pressure and macropores, it contributes less than 1.41%. For all situations, the contribution of viscous flow is more than 46.36%, and its contribution can reach up to 86.07%. Results of this study not only can improve the understanding of two-component gas transport in nanochannels, but also can lay the foundation for more reliable reservoir simulation of CO2-EGR.

Shale Gas Transport in Nanopores: Contribution of Different Transport Mechanisms and Influencing Factors

2021 ◽  
Vol 35 (3) ◽  
pp. 2033-2047
Author(s):  
Xiangyu Liu ◽  
Liehui Zhang ◽  
Yulong Zhao ◽  
Xiao He ◽  
Jianfa Wu ◽  
...  
Keyword(s):  
Influencing Factors ◽  
Shale Gas ◽  
Gas Transport ◽  
Transport Mechanisms ◽  
Shale Gas Transport

A FRACTAL PERMEABILITY MODEL FOR REAL GAS IN SHALE RESERVOIRS COUPLED WITH KNUDSEN DIFFUSION AND SURFACE DIFFUSION EFFECTS

Fractals ◽  
2020 ◽  
Vol 28 (01) ◽  
pp. 2050017 ◽  
Author(s):  
TAO WU ◽  
SHIFANG WANG
Keyword(s):  
Fractal Dimension ◽  
Surface Diffusion ◽  
Shale Gas ◽  
Gas Transport ◽  
Fractal Theory ◽  
Knudsen Diffusion ◽  
Apparent Permeability ◽  
Permeability Model ◽  
Real Gas ◽  
Shale Reservoirs

A better comprehension of the behavior of shale gas transport in shale gas reservoirs will aid in predicting shale gas production rates. In this paper, an analytical apparent permeability expression for real gas is derived on the basis of the fractal theory and Fick’s law, with adequate consideration of the effects of Knudsen diffusion, surface diffusion and flexible pore shape. The gas apparent permeability model is found to be a function of microstructural parameters of shale reservoirs, gas property, Langmuir pressure, shale reservoir temperature and pressure. The results show that the apparent permeability increases with the increase of pore area fractal dimension and the maximum effective pore radius and decreases with an increase of the tortuosity fractal dimension; the effects of Knudsen diffusion and surface diffusion on the total apparent permeability cannot be ignored under high-temperature and low-pressure circumstances. These findings can contribute to a better understanding of the mechanism of gas transport in shale reservoirs.

A review of gas transport and adsorption mechanisms in two‐component methane‐carbon dioxide system

2019 ◽  
Vol 44 (4) ◽  
pp. 2499-2516
Author(s):  
Chaohua Guo ◽  
Rongji Li ◽  
Jiwen Sun ◽  
Xin Wang ◽  
Hongji Liu
Keyword(s):  
Carbon Dioxide ◽  
Gas Transport ◽  
Adsorption Mechanisms ◽  
Two Component ◽  
Methane Carbon

The Transport Mechanisms and Dynamics of Shale via Multiscale Multiphysics Pore Network Modeling

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Saad Alafnan ◽  
I. Yucel Akkutlu
Keyword(s):  
Network Model ◽  
Shale Gas ◽  
Organic Material ◽  
Gas Transport ◽  
Network Modeling ◽  
Fluid Pressure ◽  
Pore Network ◽  
Source Rocks ◽  
Transport Mechanisms ◽  
Pore Network Modeling

Abstract Source rocks such as shale are highly heterogeneous, consisting of organic matter and various inorganic minerals. Microscopic images suggest that microcracks serve as conduits for the gas released from organic nanopores. The permeability of the shale matrix is primarily attributed to stress-sensitive microcracks that are highly influenced by changes in fluid pressure. As the microcracks are depleted, more gas molecules desorb from the organic nanopores; this, in turn, affects the fluid pressure in the microcracks. Linking the local properties of the organic nanopores to the microcracks allows for a better understanding of the coupling between them, which is necessary for improved modeling. In this research, a multiscale pore network modeling approach is presented to describe the organic material and microcrack system and investigate the large-scale features of gas transport in shale. A multiscale pore network model consisting of clusters of organic pore networks and microcracks was built to examine shale gas transport on a microscopic scale. The organic part of the network model consisted of nano-capillaries interconnected at nanopores. The network accounted for the adsorptive–convective–diffusive transport mechanisms recently derived for a single capillary. This organic nanopore network was hydraulically connected to a single microcrack. Then, the mass balance at each node in the new domain was solved, along with the assumed boundary conditions. Using the information at the nodes, the total flowrate and pressure distribution in the system were obtained as a function of time. The results show that the fluid pressure in the microcrack was primarily sensitive to the content of the organic material and its permeability. Then, the microcracks–organic materials interactions are studied and empirically quantified at larger macroscopic scale of gridblocks. This relationship can be investigated in the laboratory and used in theoretical models to predict shale gas production.

scholarly journals Numerical simulation of gas transport mechanisms in tight shale gas reservoirs

2013 ◽  
Vol 10 (4) ◽  
pp. 528-537 ◽  
Author(s):  
Jun Yao ◽  
Hai Sun ◽  
Dong-yan Fan ◽  
Chen-chen Wang ◽  
Zhi-xue Sun
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Gas Transport ◽  
Transport Mechanisms ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs
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