南海南部流体运移系统与天然气水合物富集成藏

doi:10.3969/j.issn.1001-909X.2025.01.005

摘要/Abstract

摘要：

位于南海南部的曾母-北康盆地,形成于复杂的地质构造背景下,发育了大量的油气藏和多类型的流体运移构造。地震资料表明南海南部由气烟囱、断层、管状通道、泥火山和泥底辟构成的流体运移系统,可能与水合物成藏相关,海底渗漏与似海底反射(bottom simulating reflector,简称BSR)指示了水合物存在的可能性。气烟囱形成自深部流体积聚导致的水力压裂,该水力压裂将流体运移至浅部,并且气烟囱与BSR相关,指示了水合物的富集。断层发育于深部,因与潜在烃源岩或储层相连,周围积聚了大量浅层气和水合物。麻坑是海底渗漏的指示性构造,也是冷泉水合物通常富集的区域。泥火山以及泥底辟的形成既导致了流体垂向运移,也引发了浅部地层变形和断层发育,因此其也是水合物的潜在富集区。另外,本文利用体积法对曾母-北康盆地天然气水合物的资源量进行了估算,结果表明资源量约为1.62×10¹³ m³。曾母-北康盆地具有很大的水合物资源潜力,是未来水合物勘探活动值得关注的区域。

关键词: 南海, 曾母-北康盆地, 流体运移, 天然气水合物, 油气勘探

Abstract:

The Zengmu-Beikang Basin, located in the southern South China Sea, was formed under a complex geological background, with a large number of oil and gas reservoirs developed, and various types of fluid flow structures widely distributed. Seismic data indicate that the fluid flow system composed of gas chimneys, faults, tubular channels, mud volcanoes, and mud diapirs in the southern South China Sea may be related to the accumulation of gas hydrates. Seabed seepage and bottom simulating reflection (BSR) indicate the possible existence of gas hydrates. The formation of gas chimneys originates from hydraulic fracturing caused by deep oil-gas accumulation, which transports fluids to shallow areas. The gas chimneys are related to BSR, indicating the enrichment of gas hydrates. Faults developed in deep and were connected to potential source rocks or reservoirs, thus accumulating a large amount of shallow gas and gas hydrates around the faults. Pockmark is also an indicative structure for seabed seepage and an area where cold seepage gas hydrates are usually enriched. The formation of mud volcanoes and mud diapirs not only leads to vertical fluid migration, but also triggers the shallow strata deformation and fault development. Therefore, the development areas of mud volcanoes and mud diapirs are also potential areas for gas hydrate enrichment. In addition, this article uses the volume method to estimate the gas hydrate resources in the Zengmu-Beikang Basin in the southern South China Sea. The results show that the gas hydrate resources in the Zengmu-Beikang Basin are approximately 1.62×10¹³ m³. The Zengmu-Beikang Basin has strong potential for gas hydrate resources and is a region worthy of attention for future gas hydrate exploration activities.

Key words: southern South China Sea, Zengmu-Beikang Basin, fluid flow, gas hydrate, oil-gas exploration

中图分类号:

P744.4

王修平, 杨鹏程, 刘方圆. 南海南部流体运移系统与天然气水合物富集成藏[J]. 海洋学研究, 2025, 43(1): 47-56.

WANG Xiuping, YANG Pengcheng, LIU Fangyuan. The fluid migration system and gas hydrate enrichment and accumulation in southern South China Sea[J]. Journal of Marine Sciences, 2025, 43(1): 47-56.

图/表 7

图1 南海南部曾母-北康盆地水深及构造单元划分图 (图件改绘自文献[13]。)

Fig.1 Water depth and tectonic unit division map of Zengmu-Beikang Basin in southern South China Sea (Figure was redrawn from the reference [13].)

图2 南海南部曾母盆地综合地层柱状图 (图件改绘自文献[16]。)

Fig.2 Comprehensive stratigraphic histogram of Zengmu Basin in southern South China Sea (Figure was redrawn from the reference [16].)

图3 与气烟囱和断层相关的BSR地震剖面图 (图件改绘自文献[13]和[17]。)

Fig.3 BSR seismic profiles related to gas chimneys and faults (Figures were redrawn from the references [13] and [17].)

图4 发育于碳酸盐岩等深流漂积体之上的管状通道的地震反射特征及模式图 (图件改绘自文献[13]。)

Fig.4 Seismic reflection characteristics and pattern of tubular channels developed on the deep flow drift bodies of carbonate rocks (Figures were redrawn from the reference [13].)

图5 海底麻坑的地形特征、地震反射特征及形成模式图 (图件改绘自文献[23]。)

Fig.5 Topographic characteristics, seismic reflection characteristics and formation pattern of submarine pockmarks (Figures were redrawn from the reference [23].)

图6 泥火山和泥底辟的地震反射特征图以及海底地形特征图 (图件改绘自文献[22]。)

Fig.6 Seismic reflection and seabed topography characteristics of mud volcanoes and mud diapirs (Figures were redrawn from the reference [22].)

图7 南海海底温度(a)、地温梯度(b)分布和南部水合物稳定带厚度(c)

Fig.7 Distribution map of seabed temperature (a) and geothermal gradient (b) in the South China Sea, and thickness of hydrate stability zone in southern South China Sea (c)

参考文献 27

[1]	MACELLONIA L, LUTKENB C B, GARGC S, et al. Heat-flow regimes and the hydrate stability zone of a transient, thermogenic, fault-controlled hydrate system (Woolsey Mound northern Gulf of Mexico)[J]. Marine and Petroleum Geology, 2015, 59: 491-504.
[2]	VADAKKEPULIYAMBATTA S, HORNBACH M J, BÜNZ S, et al. Controls on gas hydrate system evolution in a region of active fluid flow in the SW Barents Sea[J]. Marine and Petroleum Geology, 2015, 66: 861-872.
[3]	ANDRESEN K J. Fluid flow features in hydrocarbon plumbing systems: What do they tell us about the basin evolution?[J]. Marine Geology, 2012, 332-334: 89-108.
[4]	PAGANONI M, CARTWRIGHT J A, FOSCHI M, et al. Relationship between fluid-escape pipes and hydrate distribution in offshore Sabah (NW Borneo)[J]. Marine Geology, 2018, 395: 82-103.
[5]	KUNATH P, CRUTCHLEY G, CHI W C, et al. Episodic venting of a submarine gas seep on geological time scales: Formosa Ridge, northern South China Sea[J]. Journal of Geophysical Research: Solid Earth, 2022, 127(9): e2022JB024668.
[6]	SULTAN N, BOHRMANN G, RUFFINE L, et al. Pockmark formation and evolution in deep water Nigeria: Rapid hydrate growth versus slow hydrate dissolution[J]. Journal of Geophysical Research: Solid Earth, 2014, 119(4): 2679-2694.
[7]	吴能友, 张海啟, 杨胜雄, 等. 南海神狐海域天然气水合物成藏系统初探[J]. 天然气工业, 2007, 27(9): 1-6.
	WU N Y, ZHANG H Q, YANG S X, et al. Preliminary discussion on natural gas hydrate reservoir system of Shenhu area, North slope of South China Sea[J]. Natural Gas Industry, 2007, 27(9): 1-6.
[8]	苏丕波, 梁金强, 张伟, 等. 南海北部神狐海域天然气水合物成藏系统[J]. 天然气工业, 2020, 40(8): 77-89.
	SU P B, LIANG J Q, ZHANG W, et al. Natural gas hydrate accumulation system in the Shenhu sea area of the northern South China Sea[J]. Natural Gas Industry, 2020, 40(8): 77-89.
[9]	王秀娟, 靳佳澎, 郭依群, 等. 南海北部天然气水合物富集特征及定量评价[J]. 地球科学, 2021, 46(3):1038-1057.
	WANG X J, JIN J P, GUO Y Q, et al. The characteristics of gas hydrate accumulation and quantitative estimation in the north slope of South China Sea[J]. Earth Science, 2021, 46(3): 1038-1057.
[10]	骆帅兵, 张莉, 雷振宇, 等. 陆坡盆地体系深水重力流形成机制、沉积模式及应用实例探讨[J]. 石油实验地质, 2017, 39(6): 747-754.
	LUO S B, ZHANG L, LEI Z Y, et al. Formation mechanism, sedimentary model and typical example of a deep-water gravity flow in continental slope-basin systems[J]. Petroleum Geology & Experiment, 2017, 39(6): 747-754.
[11]	ZHANG B D, SU M, CHEN H, et al. How do fault systems and seafloor bathymetry influence the structure and distribution characteristics of gas chimneys?[J]. Basin Research, 2023, 35(5): 1718-1743.
[12]	ZHANG W, LIANG J Q, LU J A, et al. Accumulation features and mechanisms of high saturation natural gas hydrate in Shenhu Area, northern South China Sea[J]. Petroleum Exploration and Development, 2017, 44(5): 708-719.
[13]	LIU S, HERNÁNDEZ-MOLINA F J, LEI Z Y, et al. Fault-controlled contourite drifts in the southern South China Sea: Tectonic, oceanographic, and conceptual implications[J]. Marine Geology, 2021, 433(1):106420.
[14]	雷振宇, 张莉, 苏明, 等. 南海南部北康盆地中中新世深水沉积体类型、特征及意义[J]. 海洋地质与第四纪地质, 2017, 37(6): 110-118.
	LEI Z Y, ZHANG L, SU M, et al. Middle Miocene deep-water sediments in the Beikang Basin, Southern South China Sea: Types, characteristic, and implications[J]. Marine Geology & Quaternary Geology, 2017, 37(6): 110-118.
[15]	王建桥, 姚伯初, 万玲, 等. 南海海域新生代沉积盆地的油气资源[J]. 海洋地质与第四纪地质, 2005, 25(2): 91-100.
	WANG J Q, YAO B C, WAN L, et al. Characteristics of tectonic dynamics of the Cenozoic sedimentary basins and the petroleum resources in South China Sea[J]. Marine Geology & Quaternary Geology, 2005, 25(2): 91-100.
[16]	鄢伟, 张光学, 张莉, 等. 南海南部北康盆地中新世碳酸盐台地地震响应及分布特征[J]. 海洋地质与第四纪地质, 2018, 38(6): 118-126.
	YAN W, ZHANG G X, ZHANG L, et al. Seismic responses and distribution characteristics of the Miocene carbonate platforms in the Beikang Basin of Southern South China Sea[J]. Marine Geology & Quaternary Geology, 2018, 38(6): 118-126.
[17]	鄢伟, 张光学, 张莉, 等. 南海南部陆缘地质流体类型及其油气成藏意义[J]. 中国地质, 2018, 45(1): 39-47.
	YAN W, ZHANG G X, ZHANG L, et al. Focused fluid flow systems and their implications for hydrocarbon accumulations on the southern margin of South China Sea[J]. Geology in China, 2018, 45(1): 39-47.
[18]	王宏斌, 姚伯初, 梁金强, 等. 北康盆地构造特征及其构造区划[J]. 海洋地质与第四纪地质, 2001, 21(2): 49-54.
	WANG H B, YAO B C, LIANG J Q, et al. Tectonic characteristics and division of the Beikang Basin[J]. Marine Geology & Quaternary Geology, 2001, 21(2): 49-54.
[19]	BROWN A. Evaluation of possible gas microseepage mecha-nisms[J]. AAPG Bulletin, 2000, 84(11): 1775-1789.
[20]	KARSTENS J, BERNDT C. Seismic chimneys in the Southern Viking Graben-Implications for paleo fluid migration and overpressure evolution[J]. Earth and Planetary Science Letters, 2015, 412(3/4): 88-100.
[21]	MAESTRELLI D, IACOPINI D, JIHAD A A, et al. Seismic and structural characterization of fluid escape pipes using 3D and partial stack seismic from the Loyal Field (Scotland, UK): A multiphase and repeated intrusive mechanism[J]. Marine and Petroleum Geology, 2017, 88: 489-510.
[22]	HUANG W, MENG M M, ZHANG W, et al. Geological, geophysical, and geochemical characteristics of deep-routed fluid seepage and its indication of gas hydrate occurrence in the Beikang basin, southern South China Sea[J]. Marine and Petroleum Geology, 2022, 139, 105610.
[23]	ZHANG K, GUAN Y X, SONG H B, et al. A preliminary study on morphology and genesis of giant and mega pock-marks near Andu Seamount, Nansha Region (South China Sea)[J]. Marine Geophysical Research, 2020, 41: 2.
[24]	MAZZINI A, ETIOPE G. Mud volcanism: An updated review[J]. Earth-Science Reviews, 2017, 168: 81-112.
[25]	HOLBROOK W S, HOSKINS H, WOOD W T, et al. Methane hydrate and free gas on the Blake Ridge from vertical seismic profiling[J]. Science, 1996, 273: 1840-1843.
[26]	DICKENS G R, PAULL C K, WALLACE P, et al. Direct measurement of in situ methane quantities in a large gas-hydrate reservoir[J]. Nature, 1997, 385: 426-428.
[27]	孙鲁一, 张广旭, 王秀娟, 等. 南海神狐海域天然气水合物饱和度的数值模拟分析[J]. 海洋地质与第四纪地质, 2021, 41(2): 210-221.
	SUN L Y, ZHANG G X, WANG X J, et al. Numerical modeling of gas hydrate saturation for the Shenhu area, South China Sea[J]. Marine Geology & Quaternary Geology, 2021, 41(2): 210-221.