Gas migration and gas hydrate formation in marine sediments

海洋沉积物中的气体运移和天然气水合物的形成

• 批准号: 428616184
• 负责人: Professor Dr.-Ing. Klaus Wallmann
• 金额: --
• 依托单位: Fachgebiet Allgemeine Geologie / Marine Geologie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/428616184?language=en
• 关键词: Gas; migration; gas; hydrate; formation

We propose to use data generated in the IODP/OPD program to constrain numerical models of gas hydrate formation in marine sediments. In particular, we aim to better understand the fate of methane gas that is released from hydrates upon burial below the hydrate stability zone. This gas may migrate upwards to generate hydrate at the base of the stability zone or it may be removed from the stability zone by sediment burial. Very high gas hydrate saturations can be reached if methane is recycled back into the stability zone while the hydrate saturation is usually limited to < 1% if the gas cannot penetrate the pore throats and flow through the sediment matrix. Methane recycling at the base of the stability zone has been neglected in previous model studies aiming to constrain the global inventory of methane hydrate in marine sediments. Hence, the size of the hydrate inventory may be much larger than previously thought if hydrate-bound methane is recycled back into the stability zone by wide-spread gas ascent. Our proposed work is important because it may yield improved estimates of hydrate abundances. Thereby it will help to better quantify the impact of hydrate dissociation on global climate change and to validate the potential of gas hydrates as future energy resource.

我们建议使用IODP/OPD程序中产生的数据来约束海洋沉积物中天然气水合物形成的数值模型。特别是，我们的目标是更好地了解甲烷气体的命运，是从水合物的水合物稳定区以下埋藏后释放。这种气体可能向上迁移，在稳定区底部生成水合物，也可能通过沉积物埋藏从稳定区中排出。如果甲烷再循环回稳定区，则可以达到非常高的气体水合物饱和度，而如果气体不能穿透孔喉并流过沉积物基质，则水合物饱和度通常被限制在< 1%。在以往的模式研究中，稳定带底部的甲烷再循环一直被忽略，旨在限制海洋沉积物中甲烷水合物的全球库存。因此，水合物库存的大小可能比以前认为的要大得多，如果水合物结合的甲烷通过广泛的气体上升再循环回到稳定区。我们提出的工作是重要的，因为它可能会产生改进的水合物丰度的估计。这将有助于更好地量化水合物分解对全球气候变化的影响，并验证天然气水合物作为未来能源的潜力。