摘要:
天然气水合物在未来能源、环境及海洋地质灾害等方面有重要意义,是当前研究的热点。海底沉积物中含有大量的天然气水合物资源。天然气水合物稳定带厚度可用于水合物资源量的预测,在水合物资源评估中有重要意义。研究了不同因素对海底天然气水合物稳定带厚度的影响,结果表明:海水深度、地温梯度、孔隙水盐度及组成和气体组分对水合物稳定带厚度的影响不同。水合物稳定带厚度随着海水深度的增加而增大,与地温梯度呈指数递减关系;随着孔隙水盐度的增加水合物稳定带厚度减小并呈良好的线性关系,不同盐类对水合物稳定带厚度的影响程度不同;混合气体中的C2H6、CO2及H2S会使水合物稳定带厚度增加,而N2使水合物稳定带厚度减小,并且含量越大对稳定带厚度的影响越明显。
Abstract:
Natural Gas Hydrate (NGH) will play an important role as a new energy source in the near future due to its great potential and advantages. There is a great amount of gas hydrate resource occurred in submarine sediments. The thickness of gas hydrate stability zone (GHSZ) could be used as a mean to predict the resource potential of NGH, and therefore, is critical for resource evaluation. This paper studied the factors which may affect the thickness of GHSZ. Our results show that water depth, geothermal gradient, salinity and gas composition may obviously affect the thickness of GHSZ in different ways. The thickness of GHSZ increases with the water depth, and exponentially decreases with geothermal gradient. The thickness decreases linearly while the pore water salinity increases. However, different kinds of salt affect the thickness of GHSZ with different functions. The composition of vent gas controls the thickness as well. C2H6, CO2 and H2S lead the increasing in thickness of GHSZ, whereas N2 reduces the thickness of GHSZ, and the effect will be getting greater with the increase in content.
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