The effect of hydrate saturation on water retention curves in hydrate‐bearing sediments

The experimental measurement of water retention curve in hydrate‐bearing sediments is critically important to understand the behavior of hydrate dissociation and gas production. In this study, tetrahydrofuran (THF) is selected as hydrate former. The pore habit of THF hydrates is investigated by visu...

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Bibliographic Details
Published in:Geophysical research letters 2016-05, Vol.43 (9), p.4279-4287
Main Authors: Mahabadi, Nariman, Zheng, Xianglei, Jang, Jaewon
Format: Article
Language:English
Subjects:
Bearing
Capillary pressure
Dissociation
Excess water
Gas production
Hydrates
hydrate‐bearing sediment
Mathematical analysis
Mathematical models
Measurement
Oil and gas production
Pore size
Pore size distribution
Porosity
Pressure
Quartz
Retention
Saturation
Sediment
Sediments
Size distribution
Tetrahydrofuran
tetrahydrofuran hydrate
van Genuchten
Visual observation
water retention curve
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Summary:The experimental measurement of water retention curve in hydrate‐bearing sediments is critically important to understand the behavior of hydrate dissociation and gas production. In this study, tetrahydrofuran (THF) is selected as hydrate former. The pore habit of THF hydrates is investigated by visual observation in a transparent micromodel. It is confirmed that THF hydrates are not wetting phase on the quartz surface of the micromodel and occupy either an entire pore or part of pore space resulting in change in pore size distribution. And the measurement of water retention curves in THF hydrate‐bearing sediments with hydrate saturation ranging from Sh = 0 to Sh = 0.7 is conducted for excess water condition. The experimental results show that the gas entry pressure and the capillary pressure increase with increasing hydrate saturation. Based on the experimental results, fitting parameters for van Genuchten equation are suggested for different hydrate saturation conditions. Key Points THF hydrate is a nonwetting phase on the quartz grain surface with the existence of water Capillary pressure and gas entry pressure of THF hydrate‐bearing sediments increase with increasing hydrate saturation The m value governing the shape of water retention curve decreases with increasing hydrate saturation
ISSN:0094-8276
1944-8007
DOI:10.1002/2016GL068656