Shale gas transport model in 3D fractal porous media with variable pore sizes

Cai, Jianchao; Lin, Duanlin; Singh, Harpreet; Zhou, Shangwen

doi:10.1016/j.marpetgeo.2018.08.040

Cited by 135 publications

(51 citation statements)

References 61 publications

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“…Shale gas, a typical unconventional natural gas of selfgeneration and self-storage (Curtis, 2002;Hao et al, 2008;Hao et al, 2013a;Cai et al, 2018Cai et al, , 2019, mainly stores in the surface of kerogen and clay particles as adsorbed gas, and aggregates in natural fractures and nano-micron pores as free gas. In addition, a very small amount of gas stores in "in-situ" liquid and formation water as dissolved gas.…”

Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of free gas and adsorbed gas content of Wufeng-Longmaxi shales in the Jiaoshiba area, Sichuan Basin, China

Gou¹,

Xu²

2019

Adv. Geo-Energ. Res.

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Quantitative analysis of free gas and adsorbed gas contents in shale reservoirs are great significance for efficient exploration and development of shale gas. Based on the isothermal adsorption experiment of shale samples from Wufeng-Longmaxi Formation of JYA well in Jiaoshiba area and Langmuir volume model, the relationship between shale adsorption capacity and temperature, pressure, organic carbon content, quartz and clay mineral content is analyzed. Besides, the key parameters such as Langmuir volume and Langmuir pressure are dynamically calibrated by combining grey correlation method. A new model for calculating adsorbed gas and free gas is established, which takes fully into account the formation temperature, pressure, total organic carbon and shale mineral components. The results showed that the gas content of shale calculated by the new dynamic modified model is in good agreement with the actual gas content characteristics of shale reservoirs. The new model fully takes into account the vertical and horizontal heterogeneity of mineral components and its influence on shale adsorption capacity. That is not only suitable for the tectonic stability area but also for the gas content analysis in the area with strong tectonic movement. It is concluded that the modified calculation model can effectively predict the adsorbed gas, free gas and total gas content of shale reservoirs under formation conditions, which can be used as an indicator for the analysis and prediction of the exploration and development potential of shale gas wells.

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Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of free gas and adsorbed gas content of Wufeng-Longmaxi shales in the Jiaoshiba area, Sichuan Basin, China

Gou¹,

Xu²

2019

Adv. Geo-Energ. Res.

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“…And the effects of Knudsen diffusion and slip flow on production rate and cumulative production increases with the decrease of pore radius. Although the proposed study shows the importance of matrix as a significant source of gas in the total gas production, there are studies that do not endorse these results in that the importance of matrix relative to fractures in total production is insignificant.…”

Section: Resultsmentioning

confidence: 76%

A novel numerical model of gas transport in multiscale shale gas reservoirs with considering surface diffusion and Langmuir slip conditions

Huang

Cao

Yuan

et al. 2019

Energy Science & Engineering

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Multiflow mechanisms coexist in shale gas reservoirs (SGRs) due to the abundant nanopores and the organic matter as a medium of gas souring and storage. The gas transport mechanisms in nanopores including bulk gas transfer and adsorption‐gas surface diffusion were already investigated in pore‐scale models, but their effects on actual gas production of multistage fractured horizontal wells in SGRs are not clearly understood, which are crucial for the economic development of unconventional resources. Therefore, a comprehensive apparent permeability (AP) model which couples the surface diffusion of adsorbed gas, slippage flow considering the additional flux generated by surface diffusion based on Langmuir's theory, and Knudsen diffusion is established. The presented model is validated with the experimental data and lattice Boltzmann method (LBM) simulation results. Then, we propose a numerical model which combines multiflow mechanisms in microscale pores and a multistage fractured horizontal well (MSFHW) in macroscale shale gas reservoirs together. The effects of different transport mechanisms on both AP of nanopores and gas production are analyzed thoroughly. The results show that the effect of surface diffusion on the apparent permeability of nanopores is much greater than that on the actual gas production of MSFHW, and the influence of high‐pressure condition must be considered when calculating the surface diffusion coefficient. The presented numerical model has important implications for accurate numerical simulation and efficient development of shale gas reservoirs.

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“…x/100, percentage of rectangular slits pores; (1Àx/100), percentage of cylindrical pores) Pore shapes, i.e., rectangular slits and cylindrical tubes, are taken into account The quantification of the percentages of different pore types using image analysis tools is hard to implement; negligence of various pore sizes 3D fractal model [51] Please refer to Eqs. (24)- (27) in literature [51] for the specific expressions where the formulas are complex Multi-scale pore size distribution and tortuous flow line in 3D space of shale matrix are characterized Many parameters to be determined; negligence of different pore shapes Homogenization model [52,53] The homogenization method is used to upscale gas flow through two distinct constituents, a mineral matrix and organic matter. A gas flow in a twoconstituent composite The constituents, i.e., mineral matrix and organic matter, in shale are taken into account Multiple assumptions; redundant processing for model establishment and solution Method (3): the statistical sum method of the individual permeability from each shape type [49,50].…”

Section: Variations Of Viscous Flow and Diffusion With Kn (Dimensionlmentioning

confidence: 99%

“…Method 4: the 3D fractal model with variable pore sizes [51]. Method (5): the homogenization method to upscale gas flow through two distinct constituents, a mineral matrix and organic matter [52,53].…”

Section: Variations Of Viscous Flow and Diffusion With Kn (Dimensionlmentioning

confidence: 99%

Mechanism, Model, and Upscaling of the Gas Flow in Shale Matrix: Revisit

Hu¹,

Ya-Xiong²,

Li³

2022

Emerging Technologies in Hydraulic Fracturing and Gas Flow Modelling

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Shale gas accounts for an increasing proportion in the world's oil and gas supply, with the properties of low carbon, clean production, and huge potential for the compensation for the gradually depleted conventional resources. Due to the ubiquitous nanopores in shale matrix, the nanoscale gas flow becomes one of the most vital themes that are directly related to the formulation of shale gas development schemes, including the optimization of hydraulic fracturing, horizontal well spacing, etc. With regard to the gas flow in shale matrix, no commonly accepted consensus has been reached about the flow mechanisms to be considered, the coupled flow model in nanopores, and the upscaling method for its macroscopic form. In this chapter, the propositions of wall-associated diffusion, a physically sound flow mechanism scheme, a new coupled flow model in nanopores, the upscaling form of the proposed model, and the translation of lab-scale results into field-scale ones aim to solve the aforementioned issues. It is expected that this work will contribute to a deeper understanding of the intrinsic relationship among various flow mechanisms and the extension of the flow model to full flow regimes and to upscaling shale matrix, thus establishing a unified model for better guiding shale gas development.

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Shale gas transport model in 3D fractal porous media with variable pore sizes

Cited by 135 publications

References 61 publications

Quantitative evaluation of free gas and adsorbed gas content of Wufeng-Longmaxi shales in the Jiaoshiba area, Sichuan Basin, China

Quantitative evaluation of free gas and adsorbed gas content of Wufeng-Longmaxi shales in the Jiaoshiba area, Sichuan Basin, China

A novel numerical model of gas transport in multiscale shale gas reservoirs with considering surface diffusion and Langmuir slip conditions

Mechanism, Model, and Upscaling of the Gas Flow in Shale Matrix: Revisit

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