Methane hydrate phase transition in marine clayey sediments: Enhanced structure change and solid migration

Xuan Kou, Heng Zhang, Xiao-Sen Li, Zhao-Yang Chen and Yi Wang

Applied Energy, 2024, vol. 368, issue C, No S0306261924008687

Abstract: Natural gas hydrates are abundant in marine sediments and have great potential for resource development. However, there is still a lack of clarity regarding the impact of hydrate phase transition on the structure change of marine sediments. Hence, we conducted in-situ microscale experiments of hydrate phase transition in clayey sediments obtained from the active Haima cold seep area in South China Sea. By utilizing advanced X-ray Computed Tomography technology and a controlled method of hydrate phase transition, we successfully observed the dynamic behaviors of hydrate formation and decomposition, and revealed their effects on sediment structure and solid migration. Our findings suggested that methane hydrates initially occupy primary pores while generating new pores and fractures in clayey sediments. These processes lead to changes in pore morphology and anisotropy, characterized by a decrease in the degree of anisotropy and an increase in fractural and shape factor of pores. During hydrate decomposition, methane hydrates tend to be reformed in clayey sediments before initiating the decomposition process. More significantly, the combining effects of hydrates reformation and decomposition lead to occurrence of enlarged pores in sediments, resulting in unpredictable structural failure of the sediment. Furthermore, the simulation results of solid migration in sediments revealed that the solid particles migrate towards the bottom of the sediments during hydrate formation, leading to the compaction of sediment structure. Conversely, during hydrate decomposition, the solid particles move significantly towards the upper region of the sediment due to fluid seepage through newly generated and enlarged pores. The structure change and solid migration mechanisms revealed in this study highlight the potential risks during hydrate phase transition such as sediment instability and sand production, offering valuable insights into efficient and secure hydrate exploitation.

Keywords: Gas hydrate; Methane gas; Structure change; Solid migration; Marine sediments; Cold seeps (search for similar items in EconPapers)
Date: 2024
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0306261924008687
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:368:y:2024:i:c:s0306261924008687

Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/405891/bibliographic
http://www.elsevier. ... 405891/bibliographic

DOI: 10.1016/j.apenergy.2024.123485

Access Statistics for this article

Applied Energy is currently edited by J. Yan

More articles in Applied Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().