海底沉积物中天然气水合物形成过程数值模拟:以深部流体向上供给甲烷为背景

发布时间：2018-04-03 23:28

本文选题：天然气水合物　切入点：海底上升流体　出处：《海洋地质与第四纪地质》2017年01期

【摘要】：为深入了解深部上升流体供应甲烷的海底沉积环境中天然气水合物的形成和聚集过程,综合沉积作用、深部上升甲烷流体的对流和扩散作用、甲烷溶解度控制水合物形成等物理过程,建立了天然气水合物形成过程的数学模型,研究水合物在空间和时间尺度上的形成过程。模型通过3个无量纲参数(沉积压实引起的孔隙流体对流与扩散的比率Pe_1、深部流体向上对流传输与扩散的比率Pe_2、深部上升流体的甲烷含量C_(m,ext)~l),形象地描述了天然气水合物在海底沉积中的聚集过程。数值模拟研究表明,天然气水合物首先在稳定带内上部某一位置形成,随后由于沉积作用向下延伸而在稳定带底部形成水合物;水合物演化时间与Pe_1、Pe_2及C_(m,ext)~l呈负相关;水合物含量与Pe1、C_(m,ext)~l负相关,而与Pe_2正相关。甲烷溶解度曲线对水合物形成和分布有重要影响,但深部上升流体的甲烷含量、上升流体的通量决定了整个水合物系统甲烷量的输入和输出,是海底天然气水合物形成的主要控制因素。
[Abstract]:In order to understand the formation and accumulation process of natural gas hydrate in the submarine sedimentary environment where the deep ascending fluid supplies methane, the convection and diffusion of the deep ascending methane fluid can be obtained by synthesizing the deposition process.The solubility of methane controls the physical process of hydrate formation. A mathematical model of gas hydrate formation is established, and the formation process of hydrate on space and time scale is studied.The model describes natural gas graphically through three dimensionless parameters: ratio of convection and diffusion of pore fluid induced by sedimentary compaction, ratio of convection and diffusion of deep fluid, ratio of convection and diffusion, ratio of convection and diffusion of deep fluid, methane content of deep ascending fluid.The accumulation process of hydrate in submarine sediments.The numerical simulation results show that the gas hydrate is formed at a certain position in the upper part of the stable zone first, and then forms hydrate at the bottom of the stable zone due to the downward extension of sedimentary action, and the evolution time of hydrate is negatively correlated with Pe1 / P / P / 2 and C / C / M / T / T.The content of hydrate is negatively correlated with Pe1C and Pe_2.The solubility curve of methane has an important influence on the formation and distribution of hydrate. However, the methane content and flux of the ascending fluid in the deep layer determine the input and output of methane in the whole hydrate system.It is the main controlling factor of gas hydrate formation.
【作者单位】：国土资源部海底矿产资源重点实验室;中国科学院天然气水合物重点实验室中国科学院广州能源研究所;广州海洋地质调查局;国土资源部天然气水合物重点实验室青岛海洋地质研究所;中国科学院边缘海地质重点实验室中国科学院南海海洋研究所;
【基金】：国家高技术研究发展计划(863计划)项目(2013AA0925010202) 国土资源部海底矿产资源重点实验室开放基金(KLMMR-2014-B-01) 中国石油天然气集团公司与中国科学院高端战略联盟计划“天然气水合物资源评价、开采方法及安全保障技术研究”(2015A-4813)
【分类号】：P618.13;P744.4

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