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现代地质 ›› 2005, Vol. 19 ›› Issue (1): 101-107.

• 天然气水合物实验研究 • 上一篇    下一篇

天然气水合物稳定带的计算方法与参数选择探讨

王淑红1,2. 宋海斌3,4. 颜文1,4.   

  1. 1中国科学院 南海海洋研究所与广州地球化学研究所 边缘海地质重点实验室,广东 广州510301;
    2中国科学院 研究生院,北京100039;
    3中国科学院 地质与地球物理研究所,北京100029;
    4中国科学院 广州天然气水合物研究中心,广东 广州510640
  • 收稿日期:2004-11-20 修回日期:2004-12-30 出版日期:2005-01-20 发布日期:2005-01-20
  • 作者简介:王淑红,女,博士研究生,1977年出生,海洋生物学专业,从事海洋天然气水合物的研究工作。
  • 基金资助:

    中国科学院知识创新工程重要方向项目(KZCX3-SW-224,KGCX2-SW-309);中国科学院南海海洋研究所创新领域前沿项目(lyqy200312)。

Discussion of the Calculation Methods and Selection of Parameters of the Gas Hydrate Stability Zone

WANG Shu hong1,2,SONG Hai bin3,4,YAN Wen1,4   

  1. 1Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology & Guangzhou Institute of Geochemistry,Chinese Academy
          of Sciences, Guangzhou,Guangdong510301, China;
    2Graduate School of the Chinese Academy of Sciences, Beijing100039,China;
    3Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing100029, China;
    4Guangzhou Center for Gas Hydrate Research,Chinese Academy of Sciences, Guangzhou,Guangdong510640, China
  • Received:2004-11-20 Revised:2004-12-30 Online:2005-01-20 Published:2005-01-20

摘要:

天然气水合物稳定带的研究对于认识天然气水合物的成矿与分布规律以及资源评价都具有重要的指导意义。在计算稳定带厚度的不同方法之间,特别是在参数的选择上存在很大的差异。通过简单评价天然气水合物稳定带计算的几种方法和参数选择,认为选择压力计算公式时要考虑孔隙水产生的压力、海底以上水柱的压力和大气压;考虑大气压的压力随纬度变化的二阶方程是最符合实际的深度—压力转换方程;通过实验得到的方程只适用于纯水或盐度为33.5‰的海水中纯甲烷的预测;根据热力学理论可以计算不同盐度、不同气体组分的稳定带的温压条件;用相平衡图的方法最简单,但误差很大;通过四阶方程拟合实验数据和热力学数据得到的稳定带厚度更接近实际情况;不同方法预测的稳定带底界与实际含水合物沉积底界很难一致。

关键词: 天然气水合物, 稳定带, 吉布斯自由能极小化

Abstract:

The study of the gas hydrate stability zone has great significance in comprehension of the distribution features and the resource assessment of gas hydrates.Many scholars have calculated the thickness of the stability zone by different methods, but there are some big differences among these methods, especially in the selection of parameters. The authors simply evaluate several methods and the selection of parameters for the calculation of the gas hydrate stability zone. The results show that we must consider pore-water pressure, water-column pressure and atmospheric pressure when we select the pressure formula. The second-order polynomial of pressure variation with different latitudes considering atmospheric pressure is best. The obtained equation by experiment is only used to predicting pure methane of pure water or seawater of 33.5‰ salinity. We can calculate the temperature-pressure condition of stability zone with different salinities and gas compositions by the theory of thermodynamics. The phase equilibrium plot is most simple, but its error is great. The calculated thickness of stability zone by the four-order polynomial using the experiment and thermodynamics data is close to practice. The predicted limit of the stability zone by different methods is not always consistent with actual limit of hydrate sediment.

Key words: gas hydrate, stability zone, Gibbs free energy minimization

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