Gas Discharge Resistance and Medium Damage Degree as Hydrate Dissociation at Different Ambient Conditions

Xueping Chen,Lianhai Zhang,Shuaijun Li,Peng Zhang,Jing Zhan,Qingbai Wu,Yingmei Wang

doi:10.3389/fenrg.2021.712156

Abstract

For the investigation on some hydrate dissociation behaviors at different ambient conditions, methane hydrates formed inside porous media with different saturations were dissociated by depressurizations. Plots of the instantaneous flow rate of gas as dissociation versus production pressure as well as deformation of experimental sample versus accumulative amount of released gas were drawn. These two lines slopes are, respectively, characterized as gas discharge resistance and reciprocal of the latter one as damage degree of experimental samples. The results show that these formed hydrates at higher ambient conditions, that is, temperature and pressure, and possess a higher saturation, which is beneficial to discharge gas and to keep experimental samples undamaged. And the nonuniformity of dissociation processes at different layer positions induced by depressurization is inhibited significantly, especially while combining extra heating. Hydrate saturation dominates the total volume loss of these samples under loadings. These conclusions can provide reference for the prediction in gas discharge capability and media damage degree as hydrate dissociation at different experimental and natural ambient conditions.

Highlights

Natural gas hydrates are one kind of ice-like crystalline solids composed of water and gas molecules (Sloan and Koh, 2008)
Explorations via bore holes in marine sediments confirmed that natural gas hydrates occur widely in nature (Max and Lowri, 1996; Makogon et al, 2007)
The amount of carbon stored in natural gas hydrate is about twice the total amount of exploitable hydrocarbon reserves stored in the form of fossil fuels (Kvenvolden, 1988; Milkov, 2004; Wallmann et al, 2012)

Summary

Introduction

Natural gas hydrates are one kind of ice-like crystalline solids composed of water and gas molecules (Sloan and Koh, 2008). Explorations via bore holes in marine sediments confirmed that natural gas hydrates occur widely in nature (Max and Lowri, 1996; Makogon et al, 2007). These reservoirs mainly exist within marine and freshwater sediments at depths greater than 300 m (Khlystov et al, 2013; Naudts et al, 2012). The amount of carbon stored in natural gas hydrate is about twice the total amount of exploitable hydrocarbon reserves stored in the form of fossil fuels (Kvenvolden, 1988; Milkov, 2004; Wallmann et al, 2012)

Methods

Results

Conclusion