EFFECTS OF HEAT TRANSITION ON HYDRATE ACCUMULATION IN GAS VENT SITES
Received date: 2007-08-31
Revised date: 2007-10-31
Online published: 2008-06-20
Gas hydrate crystallization dissolution are exothermic/endothermic reactions, and gas venting from higher temperatures to the lower produces capacity heat, which results in the change bottom water temperature and consequently affects gas hydrate accumulation. We use the compositional kinetic model to analyze how hydrate latent heat and water capacity heat affect the gas hydrate stability in the Bush Hill. We take filter loss of venting gas as 1.8kg/(m 2·a) and there is 10% vent gas deposited as gas hydrate in the subsurface. Modeling shows that gas hydrate latent heat and water capacity heat within 10ka can perturb the temperature field in the subsurface of the Bush Hill, and thermal gradient increases 3 ℃/km at the surface of the seafloor and decreases ~1.4 ℃/km at 1km deep. The most obvious temperature variation, which is about 0.4℃,occurs in the middle part of the gas hydrate stability zone(400 mbsf deep), resulting in the reduction of hydrate stability zone by 12m and the dissolution of 0.06kg/m 2 of gas hydrate.
CAO Yuncheng,;CHEN Duofu, ;XU Wenyue . EFFECTS OF HEAT TRANSITION ON HYDRATE ACCUMULATION IN GAS VENT SITES[J]. Natural Gas Geoscience, 2007 , 18(6) : 827 -831 . DOI: 10.11764/j.issn.1672-1926.2007.06.827
［1］Sloan E D. Clathrate Hydrates of Natural Gases［M］.2nd.New York:Marcel Dekker.1998:1628.
［2］Kvenvolden K A,Lorenson T D.The global occurrence of natural gas hydrates［M］//Paull C L,Dillon W P,Washington D C.Natural Gas Hydrates: Occurrence,Distribution,and Detection.AGU,2001:318.
［3］Kvenvolden K A.Potential effects of gas hydrate on human welfare［J］.Proceedings of the National Academy of Sciences of the United States of America,1999，96 (7):34203426.
［4］苏正,陈多福.海洋天然气水合物的类型及特征［J］.大地构造与成矿学，2006，30(2):256264.
［5］苏正,陈多福.海洋环境甲烷水合物溶解度及其对水合物发育特征的控制［J］.地球物理学报，2007,50(5):待刊.
［6］樊栓狮,刘锋,陈多福.海洋天然气水合物的形成机理探讨［J］.天然气地球科学,2004,15(5):524530.
［7］Chen D F，Su Z,Cathles L M.Types of gas hydrates in marine environments and their thermodynamic characteristics［J］.Terrestrial,Atmospheric and Oceanic Sciences，2006,17（4）: 723737.
［8］Davie M K,Buffett B A.A steady state model for marine hydrate formation: Constraints on methane supply from pore water sulfate profiles［J］.J Geophys Res,2003，108(B10):2495,doi:10.1029/2002JB002300.
［9］Davie M K,Zatsepina O Y,Buffett B A.Methane solubility in marine hydrate environments［J］.Mar Geol,2004，203:177184.
［10］Xu W,Ruppel C.Predicting the occurrence,distribution,and evolution of methane gas hydrate in porous marine sediments［J］.J.Geophys.Res.,1999,104: 50815096.
［11］Chen D F,Cathles L M.A kinetic model for the pattern and amounts of hydrate precipitated from a gas steam: Application to the Bush Hill vent site,Green Canyon Block 185,Gulf of Mexico［J］.J Geophys Res,2003，108(B1):2058,doi:10.1029/ 2001JB001597.
［12］陈多福，冯东，L M Cathles.海底天然气渗漏系统水合物成藏动力学及其资源评价方法［J］.大地构造与成矿学，2005,292（2）：278284.
［13］Cathles L M,Chen D F.A compositional kinetic model of hydrate crystallization and dissolution［J］.J.Geophys.Res.,2004,109(B08102),doi:10.1029/ 2003JB002910.
［14］陈多福，冯东，陈光谦，等.海底天然气渗漏系统演化特征及对形成水合物的影响［J］.沉积学报，2005,23(2): 323328.
［15］陈多福，苏正，冯东，等.海底天然气渗漏系统水合物成藏过程及控制因素［J］.热带海洋学报，2005，24(3):19.
［16］李莉，陈多福，Cathles L M.海底天然气渗漏形成水合物的线性动力学模型［J］.地球化学,2002，31(4):395401.
［17］Baker A S.Pepper Finite Elements 123［M］.New York:McGrawHill.1991:341.
［18］Rueff R M,E D Sloan,Yesavage V F.Heat capacity and heat of dissociation of methane hydrates［J］.Am Inst Chemical Eng,1988,34:14681476.
［19］Sassen R,Losh S L,Cathles L III,et al.Massive veinfilling gas hydrate: Relation to ongoing gas migration from the deep subsurface in the Gulf of Mexico［J］.Mar Pe Geol,2001，18:551560.
［20］Leifer I,MacDonald I R.Dynamics of the gas flux from shallow gas hydrate deposits: interaction between oily hydrate bubbles and the oceanic environment［J］.Earth Planet Sci Lett,2003，21:411424.
［21］Tryon M D,Brown K M.Fluid and chemical cycling at Bush Hill: Implications for gas and hydraterich environments［J］.Geochem Geophys Geosyst,2004，5(12):Q12004,doi:10.1029/2004GC000778.
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