【摘要】 天然气水合物相变过程不仅对沉积层温度场产生影响,也会改变沉积层介电常数等物理性质,深入研究水合物相变过程对周围环境的影响对今后水合物资源开发利用以及水合物地质灾害控制评估等方面都有重要的意义。通过使用专门设计的水合物模拟实验装置,综合采用二维温度梯度和时域反射等方法对甲烷水合物生成及分解过程进行监测。结果显示:水合物合成过程中甲烷水合物合成受气源和过冷度等因素影响,当气源充足时,水合物优先在过冷度大的区域合成,否则水合物优先在气源充足的区域合成;水合物相变过程引起周围多孔介质介电常数发生改变,并可据此计算沉积层中水合物饱和度;水合物稳定性受热刺激影响明显,含水合物多孔介质传热效率与热源距离成二次函数的衰减规律。更多还原

【Abstract】 The hydrate phase transformation process not only has effect to temperature variation in sediments,but also influences the physical properties of sediments,such as dielectric constants.It is necessary to investigate the hydrate phase transformation for making good use of hydrates resource in the future.In this paper,a well-designed apparatus was used to study the hydrate formation and dissociation process.The result reveals that hydrate formation is controlled by subcooling degree and gas saturation.When the gas supply is enough,hydrates will be formed more easily in cooler region.Otherwise,it will be synthesized in high gas saturation place.The phase transformation of hydrates will cause the dielectric constant variation of sediments,and through the time domain reflection method,the hydrate saturation can be calculated.The stability of gas hydrate is obviously influenced by thermal stimulation,and the heat transportation efficiency of sediments is a quadratic function to heating source.更多还原