Modelling of gas hydrates in sedimentary systems : Methane hydrates impact on flow through porous media

• Main Author: Bello Palacios, German Alejandro
• Other Authors: orcid:0000-0002-0294-9485
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: The University of Bergen 2022
• Subjects: Methane hydrate; permafrost
• Online Access: https://hdl.handle.net/11250/2994975

In nature, gas hydrates exist in areas of permafrost and in shallow subsurface sediments at ocean depths of more than 300-500 metres. In terms of the Sustainable Development Goals (SDG) of the United Nations, better understanding of hydrates in nature can play a role in achieving energy security (SDG7), tackling climate change (SDG13) and increasing sustainability in the use of oceans (SDG14). Hydrates represent a potential energy resource as one litre of methane hydrate contains 180 litres of methane. However, if heat stress is induced by either artificial or natural causes, its destabilisation can result in the addition of more methane to the ocean-atmosphere system. At the same time, they can trigger geohazards in their natural environments. The knowledge of the gas hydrate dynamics when changes are imposed either naturally or artificially by drilling and gas exploitation is not sufficiently understood. To contribute to the understanding of gas hydrate dynamics in nature, we used a numerical simulator of hydrates in porous media to reproduce and study hydrate-related processes at different scales. The TOUGH+HYDRATE (T+H) code was the main tool used in this study. It simulates the behaviour of methane hydrate in sediments and handles both multiphase and multicomponent flow and couples heat and mass flow through porous and fractured media. To streamline the use of T+H, it was necessary to build versatile pre- and post-processing tools. These tools were written in Python and mainly process the input and output data so that the candidate could streamline access to the data, perform analysis, and prepare visualisations. The use of these tools was essential to produce the bulk of the results and accompanying figures presented in this thesis. The scientific output of this thesis consists of three scientific papers that present numerical modelling of hydrates in porous media in different scenarios. Paper 1 and paper 2 focus on modelling laboratory experiments of hydrate-bearing porous media. Paper 1 focusses on ...