南海北部陆坡细粒沉积物天然气水合物系统的形成模式初探
|
摘要
我国在南海北部陆坡的细粒沉积物中首次钻获水合物样品,为深入了解这一特殊成藏体系的形成机制,本研究以钻探区域高精度的二维和三维多道地震资料为基础,通过精细的地球物理解释和地质分析,探讨了该天然气水合物系统的成藏控制因素.细粒沉积物天然气水合物系统中水合物的富集过程存在着三个特殊的控制因素:(1)大面积丰富的含甲烷流体的参与.南海北部深水盆地广泛存在的异常热流体活动促使深部的热解成因天然气或浅层的生物成因气运移到水合物稳定带,有利于水合物的发育.热流体活动表现为底辟和气烟囱构造,在地震剖面上,表现为地震声学模糊带、同相轴下拉或中断、顶部出现反射亮点,这些构造直抵水合物稳定带.在气烟囱或底辟构造顶部通常有BSR伴生,说明热流体活动与水合物成藏具有密切关系;(2)断裂构造的发育在水合物稳定带中细粒沉积物的成核和生长过程中具有重要的作用,一方面促进稳定带流体的垂向和侧向运移,另一方面,构造裂缝可能成为成核和生长过程的空间;(3)大型海底滑坡导致了地层中超压流体活动和构造裂缝的发育,从而促进了水合物富集.在上述研究基础上,提出了南海北部水合物钻探区高饱和度水合物成藏模式.
Gas hydrate samples were obtained firstly in China by drilling on the northern margin of South China Sea (SCS).To understand the formation mechanism of this unique accumulation system,this paper discusses the factors controlling the formation of the system by accurate geophysical interpretation and geological analysis,based on the high precision 2-D and 3 D multichannel seismic data in the drilling area.There are three key factors controlling the accumulation of the gas hydrate system in fine grain sediment:(1) large volume of fluid bearing methane gas joins the formation of gas hydrate.Active fluid flow in the northern South China Sea makes both thermal gas and/or biogenic gas migrate into shallow strata and form hydrate in the gas hydrate stability zone (GHSZ).The fluid flow includes mud diapir and gas chimney structure.They are commonly characterized by positive topographic relief,acoustic turbidity and push-down,and low reflection intensity on seismic profiles.The gas chimneys can reach to GHSZ,which favors the development of BSRs.It means that the active fluid flow has a close relationship with the formation and accumulation of gas hydrate.(2) The episodic process of fracture plays an important role in the generation of gas hydrate.It may provide the passage along which thermogenic or biogenic gas migrated into gas hydrate stability zone (GHSZ) upward.And it increases the pore space for the growth of hydrate crystal.(3) Submarine landslide induced the anomalous overpressure activity and development of fracture in the GHSZ.The formation model of high concentration gas hydrate in the drilling sea area was proposed on the basis of above analysis.
Gas hydrate samples were obtained firstly in China by drilling on the northern margin of South China Sea (SCS).To understand the formation mechanism of this unique accumulation system,this paper discusses the factors controlling the formation of the system by accurate geophysical interpretation and geological analysis,based on the high precision 2-D and 3 D multichannel seismic data in the drilling area.There are three key factors controlling the accumulation of the gas hydrate system in fine grain sediment:(1) large volume of fluid bearing methane gas joins the formation of gas hydrate.Active fluid flow in the northern South China Sea makes both thermal gas and/or biogenic gas migrate into shallow strata and form hydrate in the gas hydrate stability zone (GHSZ).The fluid flow includes mud diapir and gas chimney structure.They are commonly characterized by positive topographic relief,acoustic turbidity and push-down,and low reflection intensity on seismic profiles.The gas chimneys can reach to GHSZ,which favors the development of BSRs.It means that the active fluid flow has a close relationship with the formation and accumulation of gas hydrate.(2) The episodic process of fracture plays an important role in the generation of gas hydrate.It may provide the passage along which thermogenic or biogenic gas migrated into gas hydrate stability zone (GHSZ) upward.And it increases the pore space for the growth of hydrate crystal.(3) Submarine landslide induced the anomalous overpressure activity and development of fracture in the GHSZ.The formation model of high concentration gas hydrate in the drilling sea area was proposed on the basis of above analysis.
引文
[1] Zhang H,Yang S,Wu N.GMGS-1 Science team:China's first gas hydrate expcdition successful.Fire in the Earth.Methane Hydrate Newsletter, National Technology Laboratory,US department of Energy,2007． Spring/ Summer Issue,2007,1:4～8
[2] 吴能友,张海启,杨胜雄等.南海神狐海域天然气水合物成藏系统初探.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(NGH)reservoir system of Shenhu area,north slope of South China Sea.Natural Gas Industry(in Chinese),2007,27(9) :1～6
[3] Torres M,Wallmann K,Trehu A,et al.Gas hydrate growth,methane transport,and chloride enrichment at the southern summit of Hydrate Ridge,Cascadia margin off Oregon.Earth and Planetary Sciences Letters,2004,226:225～241
[4] Trehu A,Long P,Torres M,et al.Three-dimensional distribution of gas hydrate beneath southern Hydrate Ridge:constraints from ODP Leg 204． Earth and Planetary Sciences Letters,2004,222:845～862
[5] Lee M.Gas hydrates amount estimated from acoustic logs at the Blake Ridge,sites 994,995 and 997． In:Paull C K,Matsumoto R,Wallace P J,Dillon W P(Eds.),Proceedings of the Ocean Drilling Program.Scientific Results,2000,164:193～198
[6] Trehu A,Ruppel C,Holland M,et al.Gas hydrate in marine sediments:lessons from scientific ocean drilling.Oceanology,2006,19(4) :124～142
[7] Weinberger J,Brown K,Long P.Painting a picture of gas hydrate distribution with thermal images.Geophys.Res.Lett.,2005,32:L04609
[8] 苏新.海洋天然气水合物分布与“气水沉积物”动态体系大洋钻探204航次调查初步结果的启示.中国科学(D辑)(地球科学),2004,34(12) :1091～1099 Su X.Marine gas hydrate distribution and “gas-wate-sediments” dynamic system inspiration of the ODP Leg 204 preliminary results.Science in China(Set.D,Earth Scineces)(in Chinese),2004,34(12) :1091～1099
[9] 孙珍,庞雄,钟志洪等.珠江口盆地白云凹陷新生代构造演化动力学.地学前缘,2005,12(4) :489～498 Sun Z,pang X,Zhong Z H,et al.Dynamics of Tertiary northeastern South China Sea.Chinese J.Geophys.(in Chinese),2007,50(5) :1508～1517
[13] 姚伯初.南海北部陆缘天然气水合物初探.海洋地质与第四纪地质,1998,4:11～17 Yao B C.Preliminary exploration of gas hydrate in the northern margin of the South China Sea.Marine Geology & Quaternary Geology(in Chinese),1998,4:11～17
[14] 姚伯初.南海的天然气水合物矿藏.热带海洋学报,2001,20(2) :20～28 Yao B C.The gas hydrate in the South China Sea.Tropic Oceanology(in Chinese),2001,20(2) :20～28
[15] 张光学,黄永样,祝有海等.南海天然气水合物的成矿远景.海洋地质与第四纪地质,2002,22(1) :75～81 Zhang G X,Huang Y Y,Zhu Y H,et al.Prospect of gas hydrate resources in the South China Sea.Marine Geology & Quaternary Geology(in Chinese),2002,22(1) :75～81
[16] Wu S,Zhang G,Huang Y,et al.Gas hydrate occurrence in the northern slope of the South China Sea.Mar.Petrol.Geol.,2005,23(1) :1～10
[17] Wu S,Wang X,Wong H.Low amplitude BSRs and gas hydrate concentration on the northern margin of the South China Sea.Mar.Geophys.Res.,2007,28(2) :127～138
[18] Hyndma.n R,Spence G.A seismic study of Methane Hydrate Marine Bottom simulating Reflectors.J.Geophys.Res.,1992,97(B5) :6683～6698
[19] Barthold M,Gerard T,Ruud T.Surface and subsurface expressions of gas seepages to the seabed examples from the Southern North Sea.Mar.Petrol.Geol.,2005,22:499～515
[20] Heggland R,Meldahl P,Groot P D,et al.Chimney cube unravels subsurface.American Oil and Gas Reporter,2000
[21] Meldahl P,Heggland R,Bril B,et al.Identifying faults and gas chimneys using multi-attributes and neural networks.The Leading Edge,2001,20(5) :474～482
[22] 吴时国,姚根顺,董冬冬等.南海北部陆坡大型气田区天然气水合物的成藏地质构造特征.石油学报,2008,29(3) :324～328 Wu S G,Yao G S,Dong D D,et al.Geological structures for forming gas hydrate reservoir in the huge deepwater gas field of the northern South China Sea.Acta Petrolei Sinica(in Chinese),2008,29(3) :324～328
[23] 苏正,陈多福.海洋天然气水合物的类型及特征.大地构造与成矿学,2006,30(2) :256～264 Su Z,Chen D F.Types of gas hydrates and their characteristics in marine environments.Geotectonica EtMetallogenia(in Chinese),2006,30(2) :256～264
[24] Chen D,Su Z,Cathles L.Types of gas hydrates in marine environments and their thermodynamic characteristic.TAO,2006,17(4) :723～737
[25] 张树林,陈多福,黄君权.白云凹陷天然气水合物成藏条件.天然气工业,2007,27(9) :7～10 Zhang S L,Chen D F,Huang J Q.Conditions of accumulation of gas hydrate inBaiyun sag.Natural Gas Industry(in Chinese),2007,27(9) :7～10
[26] Locat J,Lee H J.Submarine landslides.,advances and challenges.Canada Geotechology Journal,2002,39:193～212
[27] Sultton N,Voisset M,Marsset B,et al.Potential role of compressional structures in generating submarine slope failures in the Niger Delta.Mar.Geol.,2007,237:169～190
[28] 庞雄,陈长民,施和生等.相对海平面变化与南海珠江深水扇系统的响应.地学前缘,2005,12(3) ;167～177 Pang X,Chen C M,Shi H S,et al.Response between relative sea-level change and the Pearl River deep-water fan system in the South China Sea.Earth Science Frontiers(in Chinese),2005,12(3) :167～177
[29] 张为民,李继亮,钟嘉猷等.气烟囱的形成机理及其与油气的关系探讨.地质科学,2000,35(4) :449～455 Zhang W M,Li J L,Zhong J Q,et al.A study on formation mechanism of gas-chimney and relationship with petroleum.Scientia Geologica Sinica(in Chinese),2000,35(4) :449～455
[2] 吴能友,张海启,杨胜雄等.南海神狐海域天然气水合物成藏系统初探.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(NGH)reservoir system of Shenhu area,north slope of South China Sea.Natural Gas Industry(in Chinese),2007,27(9) :1～6
[3] Torres M,Wallmann K,Trehu A,et al.Gas hydrate growth,methane transport,and chloride enrichment at the southern summit of Hydrate Ridge,Cascadia margin off Oregon.Earth and Planetary Sciences Letters,2004,226:225～241
[4] Trehu A,Long P,Torres M,et al.Three-dimensional distribution of gas hydrate beneath southern Hydrate Ridge:constraints from ODP Leg 204． Earth and Planetary Sciences Letters,2004,222:845～862
[5] Lee M.Gas hydrates amount estimated from acoustic logs at the Blake Ridge,sites 994,995 and 997． In:Paull C K,Matsumoto R,Wallace P J,Dillon W P(Eds.),Proceedings of the Ocean Drilling Program.Scientific Results,2000,164:193～198
[6] Trehu A,Ruppel C,Holland M,et al.Gas hydrate in marine sediments:lessons from scientific ocean drilling.Oceanology,2006,19(4) :124～142
[7] Weinberger J,Brown K,Long P.Painting a picture of gas hydrate distribution with thermal images.Geophys.Res.Lett.,2005,32:L04609
[8] 苏新.海洋天然气水合物分布与“气水沉积物”动态体系大洋钻探204航次调查初步结果的启示.中国科学(D辑)(地球科学),2004,34(12) :1091～1099 Su X.Marine gas hydrate distribution and “gas-wate-sediments” dynamic system inspiration of the ODP Leg 204 preliminary results.Science in China(Set.D,Earth Scineces)(in Chinese),2004,34(12) :1091～1099
[9] 孙珍,庞雄,钟志洪等.珠江口盆地白云凹陷新生代构造演化动力学.地学前缘,2005,12(4) :489～498 Sun Z,pang X,Zhong Z H,et al.Dynamics of Tertiary northeastern South China Sea.Chinese J.Geophys.(in Chinese),2007,50(5) :1508～1517
[13] 姚伯初.南海北部陆缘天然气水合物初探.海洋地质与第四纪地质,1998,4:11～17 Yao B C.Preliminary exploration of gas hydrate in the northern margin of the South China Sea.Marine Geology & Quaternary Geology(in Chinese),1998,4:11～17
[14] 姚伯初.南海的天然气水合物矿藏.热带海洋学报,2001,20(2) :20～28 Yao B C.The gas hydrate in the South China Sea.Tropic Oceanology(in Chinese),2001,20(2) :20～28
[15] 张光学,黄永样,祝有海等.南海天然气水合物的成矿远景.海洋地质与第四纪地质,2002,22(1) :75～81 Zhang G X,Huang Y Y,Zhu Y H,et al.Prospect of gas hydrate resources in the South China Sea.Marine Geology & Quaternary Geology(in Chinese),2002,22(1) :75～81
[16] Wu S,Zhang G,Huang Y,et al.Gas hydrate occurrence in the northern slope of the South China Sea.Mar.Petrol.Geol.,2005,23(1) :1～10
[17] Wu S,Wang X,Wong H.Low amplitude BSRs and gas hydrate concentration on the northern margin of the South China Sea.Mar.Geophys.Res.,2007,28(2) :127～138
[18] Hyndma.n R,Spence G.A seismic study of Methane Hydrate Marine Bottom simulating Reflectors.J.Geophys.Res.,1992,97(B5) :6683～6698
[19] Barthold M,Gerard T,Ruud T.Surface and subsurface expressions of gas seepages to the seabed examples from the Southern North Sea.Mar.Petrol.Geol.,2005,22:499～515
[20] Heggland R,Meldahl P,Groot P D,et al.Chimney cube unravels subsurface.American Oil and Gas Reporter,2000
[21] Meldahl P,Heggland R,Bril B,et al.Identifying faults and gas chimneys using multi-attributes and neural networks.The Leading Edge,2001,20(5) :474～482
[22] 吴时国,姚根顺,董冬冬等.南海北部陆坡大型气田区天然气水合物的成藏地质构造特征.石油学报,2008,29(3) :324～328 Wu S G,Yao G S,Dong D D,et al.Geological structures for forming gas hydrate reservoir in the huge deepwater gas field of the northern South China Sea.Acta Petrolei Sinica(in Chinese),2008,29(3) :324～328
[23] 苏正,陈多福.海洋天然气水合物的类型及特征.大地构造与成矿学,2006,30(2) :256～264 Su Z,Chen D F.Types of gas hydrates and their characteristics in marine environments.Geotectonica EtMetallogenia(in Chinese),2006,30(2) :256～264
[24] Chen D,Su Z,Cathles L.Types of gas hydrates in marine environments and their thermodynamic characteristic.TAO,2006,17(4) :723～737
[25] 张树林,陈多福,黄君权.白云凹陷天然气水合物成藏条件.天然气工业,2007,27(9) :7～10 Zhang S L,Chen D F,Huang J Q.Conditions of accumulation of gas hydrate inBaiyun sag.Natural Gas Industry(in Chinese),2007,27(9) :7～10
[26] Locat J,Lee H J.Submarine landslides.,advances and challenges.Canada Geotechology Journal,2002,39:193～212
[27] Sultton N,Voisset M,Marsset B,et al.Potential role of compressional structures in generating submarine slope failures in the Niger Delta.Mar.Geol.,2007,237:169～190
[28] 庞雄,陈长民,施和生等.相对海平面变化与南海珠江深水扇系统的响应.地学前缘,2005,12(3) ;167～177 Pang X,Chen C M,Shi H S,et al.Response between relative sea-level change and the Pearl River deep-water fan system in the South China Sea.Earth Science Frontiers(in Chinese),2005,12(3) :167～177
[29] 张为民,李继亮,钟嘉猷等.气烟囱的形成机理及其与油气的关系探讨.地质科学,2000,35(4) :449～455 Zhang W M,Li J L,Zhong J Q,et al.A study on formation mechanism of gas-chimney and relationship with petroleum.Scientia Geologica Sinica(in Chinese),2000,35(4) :449～455
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心