Abstract
Marine hydrate reservoirs can be divided into focused high-flux and distributed low-flux gas hydrate systems according to free gas migration control mechanisms. In focused high-flux hydrate reservoirs, fluids easily break through the pressure of overlying sediments and reach the shallows, creating a series of geomorphological-geological-geophysical anomalies at and near the seafloor. Based on detailed interpretation of pre-drilling data in the eastern Pearl River Mouth Basin (PRMB), many anomalies related to the high-flux fluid flow are found, including seafloor mounds with intrusive characteristics, bright spot reflections above the bottom-stimulating reflector (BSR), phase reversals in the superficial layer, and an efficient fluid migration and accumulation system composed of fractures and uplifts. The second hydrate drilling expedition was carried out in the eastern PRMB in 2013 to study these anomalies. The acquired data show that high-flux fluid flow occurred in these sites. Gas hydrate pingoes, bright spot reflection above the BSR, and an efficient fluid migration and accumulation system can be used as identification signatures for high-flux fluid migration. The modes of high flux fluid flow are different in deep and shallow sediments during upward migration of fluid. Gas dissolved within migrating water dominates deep fluid migration and upward migration of a separate gas phase dominates the shallow process. This difference in migration models leads to formation of upper and lower concentrated hydrate reservoirs in the drilling area. The discovery of signatures of high-flux fluid flow and their migration modes will help with site selection and reduce risk in gas hydrate drilling.
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References
Anderson A L, Bryant W R. 1990. Gassy sediment occurrence and properties: Northern Gulf of Mexico. Geo-Mar Lett, 10: 209–220
Barnes R O, Goldberg E D. 1976. Methane production and consumption in anoxic marine sediments. Geology, 4: 297–300
Brooks J M, Kennicutt M C, Fay R R, McDonald T J, Sassen R. 1984. Thermogenic gas hydrates in the gulf of Mexico. Science, 225: 409–411
Brooks J M, Cox H B, Bryant W R, Kennicutt Ii M C, Mann R G, McDonald T J. 1986. Association of gas hydrates and oil seepage in the Gulf of Mexico. Org Gechem, 10: 221–234
Borowski W S, Paull C K, Ussler W. 1996. Marine pore-water sulfate profiles indicate in situ methane flux from underlying gas hydrate. Geology, 24: 655–658
Boswell R, Collett T S, Frye M, Shedd W, McConnell D R, Shelander D. 2012. Subsurface gas hydrates in the northern Gulf of Mexico. Mar Pet Geol, 34: 4–30
Chapman R, Pohlman J, Coffin R, Chanton J, Lapham L. 2004. Thermogenic gas hydrates in the northern Cascadia margin. Eos Trans AGU, 85: 361–368
Collett T S, Johnson A H, Knapp C C, Boswell R. 2009. Natural gas hydrates: A review. In: Collett T S, Johnson A H, Knapp C C, Boswell R, eds. Natural Gas Hydrates-Energy Resource Potential and Associated Geologic Hazards: AAPG Memoir 89. 146–219
Egorov A V, Crane K, Vogt P R, Rozhkov A N, Shirshov P P. 1999. Gas hydrates that outcrop on the sea floor: Stability models. Geo-Mar Lett, 19: 68–75
Evans R J, Stewart S A, Davies R J. 2007. Phase-reversed seabed reflections in seismic data: Examples related to mud volcanoes from the South Caspian Sea. Geo-Mar Lett, 27: 203–212
Han X, Suess E, Huang Y, Wu N, Bohrmann G, Su X, Eisenhauer A, Rehder G, Fang Y. 2008. Jiulong methane reef: Microbial mediation of seep carbonates in the South China Sea. Mar Geol, 249: 243–256
Huang C J, Zhou D, Sun Z, Chen C M, Hao H J. 2005. Deep crustal structure of Baiyun Sag, northern South China Sea revealed from deep seismic reflection profile. Chin Sci Bull, 50: 1131–1138
Huang Y Y, Suess E, Wu N Y. 2008. Methan and Gas Hydrate Geology of Norhtern Slope of South China Sea—Report of China-German Expedition SO-177. Beijing: Geology Publishing House
Judd A G, Hovland M. 1992. The evidence of shallow gas in marine sediments. Cont Shelf Res, 12: 1081–1095
Li L, Lei X, Zhang X, Sha Z. 2013. Gas hydrate and associated free gas in the Dongsha Area of northern South China Sea. Mar Pet Geol, 39: 92–101
MacDonald I R, Guinasso Jr N L, Sassen R, Brooks J M, Lee L, Scott K T. 1994. Gas hydrate that breaches the sea floor on the continental slope of the Gulf of Mexico. Geology, 22: 699–702
Noguchi S, Shimoda N, Takano O, Oikawa N, Inamori T, Saeki T, Fujii T. 2011. 3-D internal architecture of methane hydrate-bearing turbidite channels in the eastern Nankai Trough, Japan. Mar Pet Geol, 28: 1817–1828
Pautot G, Rangin C, Briais A, Tapponnier P, Beuzart P, Lericolais G, Mathieu X, Wu J, Han S, Li H, Lu Y, Zhao J. 1986. Spreading direction in the central South China Sea. Nature, 321: 150–154
Reeburgh W S. 1976. Methane consumption in Cariaco Trench waters and sediments. Earth Planet Sci Lett, 28: 337–344
Reeburgh W S. 1980. Anaerobic methane oxidation: Rate depth distributions in Skan Bay sediments. Earth Planet Sci Lett, 47: 345–352
Riedel M, Collett T S, Kumar P, Sathe A V, Cook A. 2010. Seismic imaging of a fractured gas hydrate system in the Krishna-Godavari Basin offshore India. Mar Pet Geol, 27: 1476–1493
Roberts H H, Hardage B A, Shedd W W, Hunt Jr J. 2006. Seafloor reflectivity—An important seismic property for interpreting fluid/gas expulsion geology and the presence of gas hydrate. Lead Edge, 25: 620–628
Ru K, Pigott J D. 1986. Episodic rifting and subsidence in the South China Sea. AAPG Bull, 70: 1136–1155
Sassen R, Sweet S T, Milkov A V, DeFreitas D A, Kennicutt II M C. 2001. Thermogenic vent gas and gas hydrate in the Gulf of Mexico slope: Is gas hydrate decomposition significant? Geology, 29: 107
Serié C, Huuse M, Schodt N H. 2012. Gas hydrate pingoes: Deep seafloor evidence of focused fluid flow on continental margins. Geology, 40: 207–210
Sha Z, Liang J, Zhang G, Yang S, Lu J, Zhang Z, McConnell D R, Humphrey G. 2015. A seepage gas hydrate system in northern South China Sea: Seismic and well log interpretations. Mar Geol, 366: 69–78
Song H B, Wu S G, Jiang W W. 2007. The characteristics of BSRs and their derived heat flowon the profile 973 in the northeastern South China Sea (in Chinese). Chin J Geophys, 50: 1508–1517
Taylor B, Hayes D E. 1980. The tectonic evolution of the South China Basin. In: Hayes D E, ed. The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands. Washington D C: American Geophysical Union. 89–104
Taylor B, Hayes D E, 1983. Origin and history of the South China Sea Basin. In: Hayes D E, ed. The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands, Part 2. Geophys Monogr. Washington D C: American Geophysical Union. 23–56
Tréhu A M, Bohrmann G, Rack F R, et al. 2003. Proceedings of the Ocean Drilling Program, Initial Reports Volume 204
Tréhu A M, Ruppel C, Holland M, Dickens G R, Torres M E, Collett T S, Goldberg D, Riedel M, Schultheiss P. 2006. Gas hydrates in marine sediments: Lessons from scientific ocean drilling. Oceanography, 19: 124–142
Wang P, Li Q. 2009. History of the South China Sea—A synthesis. In: Wang P, Li Q, eds. The South China Sea-Paleoceanography and Sedimentology. Berlin: Springer. 485–496
Xu W, Ruppel C. 1999. Predicting the occurrence, distribution, and evolution of methane gas hydrate in porous marine sediments. J Geophys Res, 104: 5081–5095
Yin P, Berné S, Vagner P, Loubrieu B, Liu Z. 2003. Mud volcanoes at the shelf margin of the East China Sea. Mar Geol, 194: 135–149
Zhang G, Liang J, Lu J, Yang S, Zhang M, Holland M, Schultheiss P, Su X, Sha Z, Xu H, Gong Y, Fu S, Wang L, Kuang Z. 2015. Geological features, controlling factors and potential prospects of the gas hydrate occurrence in the east part of the Pearl River Mouth Basin, South China Sea. Mar Pet Geol, 67: 356–367
Zhang G X, Yang S X, Ming Z, Liang Z Q, Lu J A. 2014. GMGS2 expedition investigates rich and complex gas hydrate environment in the South China Sea. Fire Ice, 14: 1–5
Acknowledgements
We are grateful to Guangzhou Marine Geological Survey for permission to publish this material. We particularly thank two anonymous reviewers for their constructive and helpful comments to improve the manuscript. This work was supported by the National Natural Science Foundation of China (Grant No. 41406068).
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Kuang, Z., Fang, Y., Liang, J. et al. Geomorphological-geological-geophysical signatures of high-flux fluid flows in the eastern Pearl River Mouth Basin and effects on gas hydrate accumulation. Sci. China Earth Sci. 61, 914–924 (2018). https://doi.org/10.1007/s11430-017-9183-y
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DOI: https://doi.org/10.1007/s11430-017-9183-y