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DOI	10.1016/j.gca.2019.07.058
	Regeneration of capillary water in unsaturated zones
	Hulin, Claudie; Mercury, Lionel
通讯作者	Hulin, Claudie
来源期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
EISSN	1872-9533
出版年	2019
卷号	265 页码:279-291
英文摘要	In porous media subject to drying conditions such as arid regions and excavation zones (deep gas injection or nuclear waste disposal), capillarity is involved in weathering processes because it modifies the geochemical and poromechanical balances within the porous network. Heterogeneous porous media like sedimentary rocks can host significant volumes of tensile capillary water in large pore bodies, and the negative pressure within is controlled by capillary forces exerted at nanometric pore throats. We have developed experiments using synthetic bimodal pore systems conducive to capillary tension. In microtubes, salts precipitated in an evaporating solution to build a dual-porosity system. A large volume (empty set200 mu m) became trapped behind nanometric pores, where high capillary tension was applied. We investigated the gas-water interactions there, especially how gas nucleated in the trapped liquid and how it subsequently changed size. After gas nucleation, the decreasing of gas volume that we observed has been attributed to two complementary geochemical effects. On the one hand, the water's tensile state increases gas solubility, as predicted by thermodynamics: capillarity is a gas-in process. On the other hand, while the total volume of the gas-water assemblage remains constant, the water's molar volume increases by capillary forces. Consequently, capillary forces exerted at the nano-throats can (re) induce a superheated monophasic liquid state from a biphasic liquid-gas assemblage even after gas nucleation. Tensions required for gas shrinkage have been estimated at 7 +/- 3 MPa and 53 +/- 15 MPa. This regeneration process offers opportunities for water to regularly return to a capillary state, making the capillary lifetime less limited than expected. This shows that pore heterogeneity in rocks submitted to drying processes results in tension for water in pores that is long-lived. As a consequence, capillarity may significantly impact the long-term geochemical budget through its effects on gas and solid solubility and/or poromechanics (compaction, tensile stress, fracturing, etc.), so that it may play an important role in the weathering of drying porous materials. (C) 2019 Elsevier Ltd. All rights reserved.
英文关键词	Thermodynamics Metastability Water retention Phase transitions
类型	Article
语种	英语
国家	France
开放获取类型	Bronze, Green Published
收录类别	SCI-E
WOS记录号	WOS:000488959900017
WOS关键词	STRESS-INDUCED CAVITATION ; CO2 STORAGE OPERATIONS ; DEEP SALINE AQUIFERS ; NEGATIVE-PRESSURE ; THERMODYNAMIC PROPERTIES ; LIQUID-WATER ; SALT PRECIPITATION ; SUPERHEATED WATER ; WELL INJECTIVITY ; HUMIDITY
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
EI主题词	2019-11-15
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/310864
作者单位	Univ Orleans, Inst Sci Terre Orleans, CNRS, BRGM,UMR 7327, 1A Rue Ferollerie, F-45071 Orleans, France
推荐引用方式 GB/T 7714	Hulin, Claudie,Mercury, Lionel. Regeneration of capillary water in unsaturated zones[J],2019,265:279-291.
APA	Hulin, Claudie,&Mercury, Lionel.(2019).Regeneration of capillary water in unsaturated zones.GEOCHIMICA ET COSMOCHIMICA ACTA,265,279-291.
MLA	Hulin, Claudie,et al."Regeneration of capillary water in unsaturated zones".GEOCHIMICA ET COSMOCHIMICA ACTA 265(2019):279-291.