Gas sorption and non-Darcy flow in shale reservoirs

Abstract Gas sorption and non-Darcy flow are two important issues for shale gas reservoirs. The sorption consists of dissolution and adsorption. Dissolved gas and adsorbed gas are different. The former is dissolved in the shale matrix, while the latter is concentrated near the solid walls of pores....

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Autores principales:	Xiukun Wang, James Sheng
Formato:	article
Lenguaje:	EN
Publicado:	KeAi Communications Co., Ltd. 2017
Materias:	Apparent gas permeability Shale Adsorbed gas Dissolved gas Surface diffusion Science Q Petrology QE420-499
Acceso en línea:	https://doaj.org/article/c5912a9f5bca44139d7ca27b7b1a8520
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spelling	oai:doaj.org-article:c5912a9f5bca44139d7ca27b7b1a85202021-12-02T00:52:51ZGas sorption and non-Darcy flow in shale reservoirs10.1007/s12182-017-0180-31672-51071995-8226https://doaj.org/article/c5912a9f5bca44139d7ca27b7b1a85202017-07-01T00:00:00Zhttp://link.springer.com/article/10.1007/s12182-017-0180-3https://doaj.org/toc/1672-5107https://doaj.org/toc/1995-8226Abstract Gas sorption and non-Darcy flow are two important issues for shale gas reservoirs. The sorption consists of dissolution and adsorption. Dissolved gas and adsorbed gas are different. The former is dissolved in the shale matrix, while the latter is concentrated near the solid walls of pores. In this paper, the Langmuir equation is used to describe adsorption and Henry’s law is used to describe dissolution. The K coefficient in Henry’s law of 0.052 mmol/(MPa g TOC) is obtained by matching experimental data. The amount of dissolved gas increases linearly when pressure increases. Using only the Langmuir equation without considering dissolution can lead to a significant underestimation of the amount of sorbed gas in shales. For non-Darcy gas flow, the apparent permeability model for free gas is established by combining slip flow and Knudsen flow. For adsorbed gas, the surface diffusion effect is also considered in this model. The surface diffusion coefficient is suggested to be of the same scale as the gas self-diffusion coefficient, and the corresponding effective permeability is derived. When $$\frac{1}{p}$$ 1 p increases, $$\frac{{k_{\text{app}} }}{{k_{\text{D}} }}$$ k app k D increases, but the relationship is not linear as the Klinkenberg effect suggests. The effect of adsorption on the gas flow is significant in nanopores ( $$r \le 2\;{\text{nm}}$$ r ≤ 2 nm ). Adsorption increases apparent permeability in shales at low pressures and decreases it at high pressures.Xiukun WangJames ShengKeAi Communications Co., Ltd.articleApparent gas permeabilityShaleAdsorbed gasDissolved gasSurface diffusionScienceQPetrologyQE420-499ENPetroleum Science, Vol 14, Iss 4, Pp 746-754 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Apparent gas permeability Shale Adsorbed gas Dissolved gas Surface diffusion Science Q Petrology QE420-499
spellingShingle	Apparent gas permeability Shale Adsorbed gas Dissolved gas Surface diffusion Science Q Petrology QE420-499 Xiukun Wang James Sheng Gas sorption and non-Darcy flow in shale reservoirs
description	Abstract Gas sorption and non-Darcy flow are two important issues for shale gas reservoirs. The sorption consists of dissolution and adsorption. Dissolved gas and adsorbed gas are different. The former is dissolved in the shale matrix, while the latter is concentrated near the solid walls of pores. In this paper, the Langmuir equation is used to describe adsorption and Henry’s law is used to describe dissolution. The K coefficient in Henry’s law of 0.052 mmol/(MPa g TOC) is obtained by matching experimental data. The amount of dissolved gas increases linearly when pressure increases. Using only the Langmuir equation without considering dissolution can lead to a significant underestimation of the amount of sorbed gas in shales. For non-Darcy gas flow, the apparent permeability model for free gas is established by combining slip flow and Knudsen flow. For adsorbed gas, the surface diffusion effect is also considered in this model. The surface diffusion coefficient is suggested to be of the same scale as the gas self-diffusion coefficient, and the corresponding effective permeability is derived. When $$\frac{1}{p}$$ 1 p increases, $$\frac{{k_{\text{app}} }}{{k_{\text{D}} }}$$ k app k D increases, but the relationship is not linear as the Klinkenberg effect suggests. The effect of adsorption on the gas flow is significant in nanopores ( $$r \le 2\;{\text{nm}}$$ r ≤ 2 nm ). Adsorption increases apparent permeability in shales at low pressures and decreases it at high pressures.
format	article
author	Xiukun Wang James Sheng
author_facet	Xiukun Wang James Sheng
author_sort	Xiukun Wang
title	Gas sorption and non-Darcy flow in shale reservoirs
title_short	Gas sorption and non-Darcy flow in shale reservoirs
title_full	Gas sorption and non-Darcy flow in shale reservoirs
title_fullStr	Gas sorption and non-Darcy flow in shale reservoirs
title_full_unstemmed	Gas sorption and non-Darcy flow in shale reservoirs
title_sort	gas sorption and non-darcy flow in shale reservoirs
publisher	KeAi Communications Co., Ltd.
publishDate	2017
url	https://doaj.org/article/c5912a9f5bca44139d7ca27b7b1a8520
work_keys_str_mv	AT xiukunwang gassorptionandnondarcyflowinshalereservoirs AT jamessheng gassorptionandnondarcyflowinshalereservoirs
_version_	1718403464488288256

Gas sorption and non-Darcy flow in shale reservoirs

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