天然气水合物区多相流体运移模型:以南海神狐海域为例
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摘要
天然气水合物是重要的海洋油气资源,近年来利用孔隙水地球化学手段结合流体反应运移模型对水合物进行勘探已成为研究热点。文章针对南海神狐海域钻探GMGS-1航次的数据资料,用孔隙水溴碘摩尔数比值拟合全新世流体运移速率,构建了二期次非稳态水合物多相流体运移模型,并以SH7站位作为应用,发现自更新世以来研究区水合物成藏系统处于衰退状态。通过模型参数敏感性分析,了解到影响模型输出的参数权重从高到低依次是沉积物孔隙度、有机质含量和沉积埋藏速率。进一步数值分析表明,在水合物成藏系统中,有机质含量与水合物饱和度满足线性相关,其他主要参数与饱和度的关系并非单调函数,且主导水合物稳定区内的甲烷物源是深部外源流体所携带的甲烷。多相流体运移模型对水合物资源勘查具有一定的理论意义。
Gas hydrates are one of the significant offshore petroleum resources. The exploration of hydrates using combined porewater geochemistry and fluid reaction-transport modelling has become an important proxy in researches of recent years. Based on the data of GMGS-1 drilling project from the Shenhu area of the South China Sea, the advection velocity of porewater during the Holocene was fitted by the molar ratio of bromine to iodine, and a two-stage non-steady state multiphase fluid transport model of the gas hydrate zone was constructed. We found that the hydrate accumulation in the study area, i.e. Site SH7, was in decline since the Pleistocene. Through sensitivity analysis of model parameters, it was learned that the parameter weights affecting the output were sediment porosity, organic matter content and sediment burial rate in descending order. Further numerical analysis shows that in the hydrate accumulation system, hydrate saturation is proportional to organic matter content, but shows a non-monotonic dependence on other main parameters. Besides, it is the external methane from deep below dominates the methane source in the hydrate stability zone. The multiphase fluid transport model of this study provides theoretical basis for the exploration of hydrate resources.
Gas hydrates are one of the significant offshore petroleum resources. The exploration of hydrates using combined porewater geochemistry and fluid reaction-transport modelling has become an important proxy in researches of recent years. Based on the data of GMGS-1 drilling project from the Shenhu area of the South China Sea, the advection velocity of porewater during the Holocene was fitted by the molar ratio of bromine to iodine, and a two-stage non-steady state multiphase fluid transport model of the gas hydrate zone was constructed. We found that the hydrate accumulation in the study area, i.e. Site SH7, was in decline since the Pleistocene. Through sensitivity analysis of model parameters, it was learned that the parameter weights affecting the output were sediment porosity, organic matter content and sediment burial rate in descending order. Further numerical analysis shows that in the hydrate accumulation system, hydrate saturation is proportional to organic matter content, but shows a non-monotonic dependence on other main parameters. Besides, it is the external methane from deep below dominates the methane source in the hydrate stability zone. The multiphase fluid transport model of this study provides theoretical basis for the exploration of hydrate resources.
引文
何丽娟,雷兴林,张毅.2011.南海北部神狐海域天然气水合物形成聚集的数值模拟研究[J].地球物理学报,54:1285.
黄永样.2008.南海北部陆坡甲烷和天然气水合物地质:中德合作SO-177航次成果专报[M].北京:地质出版社.
贾承造,张永峰,赵霞.2014.中国天然气工业发展前景与挑战[J].天然气工业,34:1.
吕宝凤,袁亚娟.2008.南海北部深水盆地沉积-构造的差异性及其油气意义[J].大地构造与成矿学,441-447.
宁伏龙,吴能友,李实,等.2013.基于常规测井方法估算原位水合物储集层力学参数[J].石油勘探与开发,507-512.
吴能友,杨胜雄,王宏斌,等.2009.南海北部陆坡神狐海域天然气水合物成藏的流体运移体系[J].地球物理学报,52:1641.
薛禹群,吴吉春.2010.地下水动力学[M].北京:地质出版社.
杨涛,叶鸿,赖亦君.2017.南海北部陆坡天然气水合物的沉积物孔隙水地球化学研究进展[J].海洋地质与第四纪地质,(5):48-58.
姚伯初.1996.南海海盆新生代的构造演化史[J].海洋地质与第四纪地质,1-13.
Bangs L N,Dale S S and Xenia G.1993.Free gas at the base of the gas hydrate zone in the vicinity of the Chile triple junction[J].Geology,21:905-908.
Bear J.1972.Dynamics of Fluids In Porous Media[M].American Elsevier Publishing Company:764.
Berner A R.1980.Early Diagenesis:A Theoretical Approach[M].Princeton University Press:256.
Berner A R.1971.Principles of Chemical Sedimentology[M].McGrawHill:240.
Bhatnagar G,Chatterjee S,Chapman G,et al.2011.Analytical theory relating the depth of the sulfate-methane transition to gas hydrate distribution and saturation[J].Geochemistry Geophysics Geosystems,12.
Boudreau P B.1997.Diagenetic Models and Their Implementation:Modelling Transport and Reactions in Aquatic Sediments[M].Springer:414.
Brown M K,Bangs L N,Froelich N P,et al.1996.The nature,distribution,and origin of gas hydrate in the Chile Triple Junction region[J].Earth and Planetary Science Letters,139:471-483.
Burdige J D.2006.Geochemistry of Marine Sediments[M].Princeton University Press:624.
Chatterjee S,Dickens R G,Bhatnagar G,et al.2011.Pore water sulfate,alkalinity,and carbon isotope profiles in shallow sediment above marine gas hydrate systems:A numerical modeling perspective[J].Journal of Geophysical Research:Solid Earth,116.
Chester R.2012.Marine Geochemistry[M].Springer Netherlands:420.
Davie K M,Zatsepina Y O and Buffett A B.2004.Methane solubility in marine hydrate environments[J].Marine Geology,203:177-184.
Davie K M and Buffett A B.2001.A numerical model for the formation of gas hydrate below the seafloor[J].Journal of Geophysical Research:Solid Earth,106(B1):497-514.
Davie K M and Buffett A B.2003.A steady state model for marine hydrate formation:Constraints on methane supply from pore water sulfate profiles[J].Journal of Geophysical Research:Solid Earth,108.
Egeberg K P and Dickens R G.1999.Thermodynamic and pore water halogen constraints on gas hydrate distribution at ODP Site 997(Blake Ridge)[J].Chemical Geology,153:53-79.
Emerson S and Hedges I J.1988.Processes controlling the organic carbon content of open ocean sediments[J].Paleoceanography,3:621-634.
Garg S K,Pritchett J W,Katoh A,et al.2008.A mathematical model for the formation and dissociation of methane hydrates in the marine environment[J].Journal of Geophysical Research,113,B01201.
Gorman R A,Holbrook S W,Hornbach J M,et al.2002.Migration of methane gas through the hydrate stability zone in a low-flux hydrate province[J].Geology,30:327-330.
Hensen C and Wallmann K.2005.Methane formation at Costa Rica continental margin--constraints for gas hydrate inventories and cross-décollement fluid flow[J].Earth and Planetary Science Letters,236:41-60.
Hesse R.2003.Pore water anomalies of submarine gas-hydrate zones as tool to assess hydrate abundance and distribution in the subsurface[J].Earth-Science Reviews,61:149-179.
Hesse R and Harrison E W.1981.Gas hydrates(clathrates)causing porewater freshening and oxygen isotope fractionation in deep-water sedimentary sections of terrigenous continental margins[J].Earth and Planetary Science Letters,55:453-462.
Hyndman D R and Spence D G.1992.A seismic study of methane hydrate marine bottom simulating reflectors[J].Journal of Geophysical Research:Solid Earth,97:6683-6698.
Iversen N J and rgensen B B.1985.Anaerobic methane oxidation rates at the sulfate-methane transition in marine sediments from Kattegat and Skagerrak(Denmark)1[J].Limnology and Oceanography,30(5):944-955.
Jiang S Y,Yang T,Ge L,et al.2008.Geochemical anomaly of pore waters and implications for gas hydrate occurrence in the South China Sea[C]//Proceedings of the 6th International Conference on Gas Hydrates.ICGH
Lüdmann T and Wong K H.1999.Neotectonic regime on the passive continental margin of the northern South China Sea[J].Tectonophysics,311:113-138.
Liu X and Flemings B P.2007.Dynamic multiphase flow model of hydrate formation in marine sediments[J].Journal of Geophysical Research:Solid Earth,112.
Malinverno A,Kastner M,Torres E M,et al.2008.Gas hydrate occurrence from pore water chlorinity and downhole logs in a transect across the northern Cascadia margin(Integrated Ocean Drilling Program Expedition 311)[J].Journal of Geophysical Research:Solid Earth,113.
Milkov V A,Dickens R G,Claypool E G,et al.2004.Co-existence of gas hydrate,free gas,and brine within the regional gas hydrate stability zone at Hydrate Ridge(Oregon margin):evidence from prolonged degassing of a pressurized core[J].Earth and Planetary Science Letters,222:829-843.
Miller J J,Lee W M and von Huene R.1991.An analysis of a seismic reflection from the base of a gas hydrate zone,offshore Peru[J].Aapg Bulletin,75:910-924.
Paull K C,Ussler III W and Borowski S W.1994.Sources of biogenic methane to form marine gas hydrates in situ production or upward migration[J].Annals of the New York Academy of Sciences,715:392-409.
Reeburgh W S.2007.Oceanic methane biogeochemistry[J].Chemical Reviews,107(2):486-513.
Rempel W A and Buffett A B.1997.Formation and accumulation of gas hydrate in porous media[J].Journal of Geophysical Research:Solid Earth,102:10151-10164.
Saltelli A,Ratto M,Andres T,et al.2008.Global Sensitivity Analysis:The Primer[M].Wiley:304.
Saltelli A,Ratto M,Tarantola S,et al.2005.Sensitivity Analysis for Chemical Models[J].Chemical Reviews,105:2811-2828.
Schulz D H and Zabel M.2006.Marine Geochemistry[M].Springer Berlin Heidelberg:574.
Sloan D E and Koh C.2007.Clathrate Hydrates of Natural Gases[M].CRC Press:752.
Su M,Yang R,Wang H,et al.2016.Gas hydrates distribution in the Shenhu Area,northern South China Sea:comparisons between the eight drilling sites with gas-hydrate petroleum system[J].Geologica Acta,79-100.
Su Z,Cao Y,Wu N,et al.2012.Numerical investigation on methane hydrate accumulation in Shenhu Area,northern continental slope of South China Sea[J].Marine and Petroleum Geology,38:158-165.
Taylor H M,Dillon P W and Pecher A I.2000.Trapping and migration of methane associated with the gas hydrate stability zone at the Blake Ridge Diapir:new insights from seismic data[J].Marine Geology,164:79-89.
Wu L,Yang S,Liang J,et al.2013.Variations of pore water sulfate gradients in sediments as indicator for underlying gas hydrate in Shenhu Area,the South China Sea[J].Science China Earth Sciences,56(4):530-540.
Wu N,Zhang H,Yang S,et al.2011.Gas hydrate system of Shenhu area,Northern South China Sea:geochemical results[J].Journal of Geological Research,Vol.2011.
Xu W and Ruppel C.1999.Predicting the occurrence,distribution,and evolution of methane gas hydrate in porous marine sediments[J].Journal of Geophysical Research:Solid Earth,104:5081-5095.
Yang S,Liang J,Lei Y,et al.2017.GMGS4 gas hydrate drilling expedition in the South China Sea[J].Fire in the Ice:Methane Hydrate Newsletter,17:1-5.
Yang S,Zhang M,Liang J,et al.2015.Preliminary results of China’s third gas hydrate drilling expedition:A critical step from discovery to development in the South China Sea[J].Fire in the Ice:Methane Hydrate Newsletter,15:1-5.
Zhang G,Yang S,Zhang M,et al.2014.GMGS2 expedition investigates rich and complex gas hydrate environment in the South China Sea[J].Fire in the Ice:Methane Hydrate Newsletter,14:1-5.
Zheng C and Bennett D G.2002.Applied Contaminant Transport Modeling[M].Wiley:656.
黄永样.2008.南海北部陆坡甲烷和天然气水合物地质:中德合作SO-177航次成果专报[M].北京:地质出版社.
贾承造,张永峰,赵霞.2014.中国天然气工业发展前景与挑战[J].天然气工业,34:1.
吕宝凤,袁亚娟.2008.南海北部深水盆地沉积-构造的差异性及其油气意义[J].大地构造与成矿学,441-447.
宁伏龙,吴能友,李实,等.2013.基于常规测井方法估算原位水合物储集层力学参数[J].石油勘探与开发,507-512.
吴能友,杨胜雄,王宏斌,等.2009.南海北部陆坡神狐海域天然气水合物成藏的流体运移体系[J].地球物理学报,52:1641.
薛禹群,吴吉春.2010.地下水动力学[M].北京:地质出版社.
杨涛,叶鸿,赖亦君.2017.南海北部陆坡天然气水合物的沉积物孔隙水地球化学研究进展[J].海洋地质与第四纪地质,(5):48-58.
姚伯初.1996.南海海盆新生代的构造演化史[J].海洋地质与第四纪地质,1-13.
Bangs L N,Dale S S and Xenia G.1993.Free gas at the base of the gas hydrate zone in the vicinity of the Chile triple junction[J].Geology,21:905-908.
Bear J.1972.Dynamics of Fluids In Porous Media[M].American Elsevier Publishing Company:764.
Berner A R.1980.Early Diagenesis:A Theoretical Approach[M].Princeton University Press:256.
Berner A R.1971.Principles of Chemical Sedimentology[M].McGrawHill:240.
Bhatnagar G,Chatterjee S,Chapman G,et al.2011.Analytical theory relating the depth of the sulfate-methane transition to gas hydrate distribution and saturation[J].Geochemistry Geophysics Geosystems,12.
Boudreau P B.1997.Diagenetic Models and Their Implementation:Modelling Transport and Reactions in Aquatic Sediments[M].Springer:414.
Brown M K,Bangs L N,Froelich N P,et al.1996.The nature,distribution,and origin of gas hydrate in the Chile Triple Junction region[J].Earth and Planetary Science Letters,139:471-483.
Burdige J D.2006.Geochemistry of Marine Sediments[M].Princeton University Press:624.
Chatterjee S,Dickens R G,Bhatnagar G,et al.2011.Pore water sulfate,alkalinity,and carbon isotope profiles in shallow sediment above marine gas hydrate systems:A numerical modeling perspective[J].Journal of Geophysical Research:Solid Earth,116.
Chester R.2012.Marine Geochemistry[M].Springer Netherlands:420.
Davie K M,Zatsepina Y O and Buffett A B.2004.Methane solubility in marine hydrate environments[J].Marine Geology,203:177-184.
Davie K M and Buffett A B.2001.A numerical model for the formation of gas hydrate below the seafloor[J].Journal of Geophysical Research:Solid Earth,106(B1):497-514.
Davie K M and Buffett A B.2003.A steady state model for marine hydrate formation:Constraints on methane supply from pore water sulfate profiles[J].Journal of Geophysical Research:Solid Earth,108.
Egeberg K P and Dickens R G.1999.Thermodynamic and pore water halogen constraints on gas hydrate distribution at ODP Site 997(Blake Ridge)[J].Chemical Geology,153:53-79.
Emerson S and Hedges I J.1988.Processes controlling the organic carbon content of open ocean sediments[J].Paleoceanography,3:621-634.
Garg S K,Pritchett J W,Katoh A,et al.2008.A mathematical model for the formation and dissociation of methane hydrates in the marine environment[J].Journal of Geophysical Research,113,B01201.
Gorman R A,Holbrook S W,Hornbach J M,et al.2002.Migration of methane gas through the hydrate stability zone in a low-flux hydrate province[J].Geology,30:327-330.
Hensen C and Wallmann K.2005.Methane formation at Costa Rica continental margin--constraints for gas hydrate inventories and cross-décollement fluid flow[J].Earth and Planetary Science Letters,236:41-60.
Hesse R.2003.Pore water anomalies of submarine gas-hydrate zones as tool to assess hydrate abundance and distribution in the subsurface[J].Earth-Science Reviews,61:149-179.
Hesse R and Harrison E W.1981.Gas hydrates(clathrates)causing porewater freshening and oxygen isotope fractionation in deep-water sedimentary sections of terrigenous continental margins[J].Earth and Planetary Science Letters,55:453-462.
Hyndman D R and Spence D G.1992.A seismic study of methane hydrate marine bottom simulating reflectors[J].Journal of Geophysical Research:Solid Earth,97:6683-6698.
Iversen N J and rgensen B B.1985.Anaerobic methane oxidation rates at the sulfate-methane transition in marine sediments from Kattegat and Skagerrak(Denmark)1[J].Limnology and Oceanography,30(5):944-955.
Jiang S Y,Yang T,Ge L,et al.2008.Geochemical anomaly of pore waters and implications for gas hydrate occurrence in the South China Sea[C]//Proceedings of the 6th International Conference on Gas Hydrates.ICGH
Lüdmann T and Wong K H.1999.Neotectonic regime on the passive continental margin of the northern South China Sea[J].Tectonophysics,311:113-138.
Liu X and Flemings B P.2007.Dynamic multiphase flow model of hydrate formation in marine sediments[J].Journal of Geophysical Research:Solid Earth,112.
Malinverno A,Kastner M,Torres E M,et al.2008.Gas hydrate occurrence from pore water chlorinity and downhole logs in a transect across the northern Cascadia margin(Integrated Ocean Drilling Program Expedition 311)[J].Journal of Geophysical Research:Solid Earth,113.
Milkov V A,Dickens R G,Claypool E G,et al.2004.Co-existence of gas hydrate,free gas,and brine within the regional gas hydrate stability zone at Hydrate Ridge(Oregon margin):evidence from prolonged degassing of a pressurized core[J].Earth and Planetary Science Letters,222:829-843.
Miller J J,Lee W M and von Huene R.1991.An analysis of a seismic reflection from the base of a gas hydrate zone,offshore Peru[J].Aapg Bulletin,75:910-924.
Paull K C,Ussler III W and Borowski S W.1994.Sources of biogenic methane to form marine gas hydrates in situ production or upward migration[J].Annals of the New York Academy of Sciences,715:392-409.
Reeburgh W S.2007.Oceanic methane biogeochemistry[J].Chemical Reviews,107(2):486-513.
Rempel W A and Buffett A B.1997.Formation and accumulation of gas hydrate in porous media[J].Journal of Geophysical Research:Solid Earth,102:10151-10164.
Saltelli A,Ratto M,Andres T,et al.2008.Global Sensitivity Analysis:The Primer[M].Wiley:304.
Saltelli A,Ratto M,Tarantola S,et al.2005.Sensitivity Analysis for Chemical Models[J].Chemical Reviews,105:2811-2828.
Schulz D H and Zabel M.2006.Marine Geochemistry[M].Springer Berlin Heidelberg:574.
Sloan D E and Koh C.2007.Clathrate Hydrates of Natural Gases[M].CRC Press:752.
Su M,Yang R,Wang H,et al.2016.Gas hydrates distribution in the Shenhu Area,northern South China Sea:comparisons between the eight drilling sites with gas-hydrate petroleum system[J].Geologica Acta,79-100.
Su Z,Cao Y,Wu N,et al.2012.Numerical investigation on methane hydrate accumulation in Shenhu Area,northern continental slope of South China Sea[J].Marine and Petroleum Geology,38:158-165.
Taylor H M,Dillon P W and Pecher A I.2000.Trapping and migration of methane associated with the gas hydrate stability zone at the Blake Ridge Diapir:new insights from seismic data[J].Marine Geology,164:79-89.
Wu L,Yang S,Liang J,et al.2013.Variations of pore water sulfate gradients in sediments as indicator for underlying gas hydrate in Shenhu Area,the South China Sea[J].Science China Earth Sciences,56(4):530-540.
Wu N,Zhang H,Yang S,et al.2011.Gas hydrate system of Shenhu area,Northern South China Sea:geochemical results[J].Journal of Geological Research,Vol.2011.
Xu W and Ruppel C.1999.Predicting the occurrence,distribution,and evolution of methane gas hydrate in porous marine sediments[J].Journal of Geophysical Research:Solid Earth,104:5081-5095.
Yang S,Liang J,Lei Y,et al.2017.GMGS4 gas hydrate drilling expedition in the South China Sea[J].Fire in the Ice:Methane Hydrate Newsletter,17:1-5.
Yang S,Zhang M,Liang J,et al.2015.Preliminary results of China’s third gas hydrate drilling expedition:A critical step from discovery to development in the South China Sea[J].Fire in the Ice:Methane Hydrate Newsletter,15:1-5.
Zhang G,Yang S,Zhang M,et al.2014.GMGS2 expedition investigates rich and complex gas hydrate environment in the South China Sea[J].Fire in the Ice:Methane Hydrate Newsletter,14:1-5.
Zheng C and Bennett D G.2002.Applied Contaminant Transport Modeling[M].Wiley:656.