南海天然气水合物稳定带厚度分布特征

天然气水合物在未来能源、自然环境和灾害等方面具有重要的研究意义，其形成除需要充足的气源外，还与温度、压力密切相关。天然气水合物稳定带表明该地区水合物发育与分布的可能范围。以Dickens和Quinby Hunt的甲烷水合物相平衡公式为基础，从地热学角度分析南海甲烷水合物稳定带厚度及其分布特征。研究表明，南海大部分海域均具备形成天然气水合物的条件。由于受海底深度、海底温度、热流等参数的影响，在不同位置发育的水合物稳定带厚度变化较大，最大厚度可达1 100 m，位于吕宋海槽内。水合物稳定带厚度较大的区域主要呈条带状分布在南海中部和东部，大陆边缘水深500 m左右即可形成水合物，说明南海地区具有广泛的天然气水合物形成环境。天然气水合物稳定带厚度仅是水合物厚度的理论值，地层中实际的水合物发育厚度和分布特征还受到气源、构造、沉积等因素的影响。此外，岩石热导率、海底温度、热流和水深等对南海水合物稳定带厚度及其分布有影响。

The Distribution Characteristics of the Thickness of Gas Hydrate Stability Zone in South China Sea

Gas hydrate has important research significances in future energy,natural environment and disaster.Its formation needs sufficient gas supply,and also has close relationships with temperature and pressure.The thickness of gas hydrate stability zone(GHSZ) shows the possible range of hydrate development and distribution.The paper analyzes the thickness and distribution of GHSZ in South China Sea on the basis of the hydrate phase equilibrium formula by Dickens and Quinby-Hunt in the view point of geothermic.The thickness of GHSZ changes greatly in different locations and reaches up to 1,100 meters in Luzon Trench.The thicker area distributes in the central and the eastern like a belt.All of these illuminate that South China Sea has the environment for hydrate formation.The calculated value of GHSZ is just a theoretical value,the real value in sediment and distribution characteristics of GHSZ affected by other factors,such as gas hydrate source,structure and sediment,etc.Thermal conductivity and sea floor temperature affect the thickness and distribution of GHSZ.It also has close correlation with the characteristic of heat flow and submarine topography in South China Sea.