Stability of hydrate-bearing sediment during methane hydrate production by depressurization or intermittent CO2/N2 injection

Yi-Jian Zhu, Yan-Song Chu, Xing Huang, Ling-Ban Wang, Xiao-Hui Wang, Peng Xiao, Yi-Fei Sun, Wei-Xin Pang, Qing-Ping Li, Chang-Yu Sun and Guang-Jin Chen

Energy, 2023, vol. 269, issue C

Abstract: Ensuring reservoir stability during natural gas hydrates production is the key to balance the geology-engineering-environment nexus. Under the overlying stress of 10 MPa, a series of experiments were conducted to investigate the variations of P-wave velocity, subsidence, and stratum stiffness during hydrate depressurization mining. The influence of hydrate saturations, gas production pressure, and sediment type were examined. The stratum stiffness of hydrate-bearing sediment gradually decreased with the decomposition of hydrate, despite the continuous compaction of overlying stress. Higher hydrate saturation led to larger subsidence and slower sedimentation rate. Lower gas production pressure resulted in greater subsidence and faster sedimentation rate. In sandy sediments, a larger particle size generated a larger sedimentation rate due to the strong heterogeneity of hydrate. However, the subsidence of silty clay is smaller with slower sedimentation rate. Hence, a novel method of intermittent CO2/N2 injection below the freezing point was proposed, which kept the stratum stiffness, reduced the sedimentation rate and subsidence of the reservoir, but also realized the sequestration of CO2 simultaneously. The method greatly enhanced the recovery ratio of methane hydrate below the freezing point. These findings provide guidance for the safe and efficient exploitation of natural gas hydrate in future.

Keywords: Gas hydrate; Stratum stiffness; Subsidence; Depressurization; Below the freezing point; Intermittent CO2/N2 injection mode (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544223002190
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:energy:v:269:y:2023:i:c:s0360544223002190

DOI: 10.1016/j.energy.2023.126825

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

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