气候变化领域集成服务门户(CCPortal): Salt-driven evolution of a gas hydrate reservoir in Green Canyon; Gulf of Mexico

CCPortal

DOI	10.1306/10151818125
	Salt-driven evolution of a gas hydrate reservoir in Green Canyon; Gulf of Mexico
	Portnov A.; Cook A.E.; Heidari M.; Sawyer D.E.; Santra M.; Nikolinakou M.
发表日期	2020
ISSN	0149-1423
起始页码	1903
结束页码	1919
卷号	104 期号:9
英文摘要	The base of the gas hydrate stability zone (GHSZ) is a critical interface, providing a first-order estimate of gas hydrate distribution. Sensitivity to thermobaric conditions makes its prediction challenging, particularly in the regions with dynamic pressure-temperature regime. In Green Canyon Block 955 (GC 955) in the northern Gulf of Mexico, the seismically inferred base of the GHSZ is 450 m (1476 ft) below the seafloor, which is 400 m (1312 ft) shallower than predicted by gas hydrate stability modeling using standard temperature and pressure gradient assumptions and an assumption of structure I (99.9% methane gas) gas hydrate. We use three-dimensional seismic log data and heat-flow modeling to explain the factor of the salt diapir on the observed thinning of the GHSZ. We also test the alternative hypothesis that the GHSZ base is actually consistent with the theoretical depth. The heat-flow model indicates a salt-induced temperature anomaly, reaching 8°C at the reservoir level, which is sufficient to explain the position of the base of the GHSZ. Our analyses show that overpressure does develop at GC 955, but only within an approximately 500-m (~1640-ft)-thick sediment section above the salt top, which does not currently affect the pressure field in the GHSZ (~1000 m [~328 ft] above salt). Our study confirms that a salt diapir can produce a strong localized perturbation of the temperature and pressure regime and thus on the stability of gas hydrates. Based on our results, we propose a generalized evolution mechanism for similar reservoirs, driven by salt-controlled gas hydrate formation and dissociation elsewhere in the world. Copyright ©2020. The American Association of Petroleum Geologists. All rights reserved.
英文关键词	Gas hydrates; Gases; Heat transfer; Hydration; Salt tectonics; Alternative hypothesis; Gas hydrate stabilities; Gas hydrate stability zones; Localized perturbation; Northern Gulf of Mexico; Standard temperature and pressures; Temperature and pressures; Thermobaric conditions; Phase interfaces; gas hydrate; high pressure system; reservoir characterization; seafloor; sediment analysis; sediment thickness; seismic data; temperature profile; three-dimensional modeling; Atlantic Ocean; Green Canyon; Gulf of Mexico
语种	英语
来源期刊	AAPG Bulletin
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/168692
作者单位	School of Earth Sciences, Ohio State University, Columbus, OH, United States; Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, Arctic University of Norway, Tromsø, Norway; Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States
推荐引用方式 GB/T 7714	Portnov A.,Cook A.E.,Heidari M.,et al. Salt-driven evolution of a gas hydrate reservoir in Green Canyon; Gulf of Mexico[J],2020,104(9).
APA	Portnov A.,Cook A.E.,Heidari M.,Sawyer D.E.,Santra M.,&Nikolinakou M..(2020).Salt-driven evolution of a gas hydrate reservoir in Green Canyon; Gulf of Mexico.AAPG Bulletin,104(9).
MLA	Portnov A.,et al."Salt-driven evolution of a gas hydrate reservoir in Green Canyon; Gulf of Mexico".AAPG Bulletin 104.9(2020).