| Summary: | Natural gas hydrate (NGH) is a solid phase consisting of water and natural gas. NGH represents a justified vast global energy resource, and is widespread in on-shore artic and sub-seafloor environments. Due to the worlds increasing demand for energy, and pressing environmental issues, methane (CH4) production from NGH represent a favorable option towards more energy security and sustainability. This thesis presents a series of experiments conducted on sandstone core samples. The main focus of the experiments was to gather data from hydrate formation and different gas productions schemes in porous media. The results from the experiment contribute to an in-house database which is used to develop numerical models for hydrate systems. Bentheimer sandstone was used in all the core scale experiments. All the cores were saturated with 3.5wt% NaCl prior to the experiments and had fairly high initial water saturation in the range of 0.57-070. CH4 hydrate formation was conducted in 15 different Bentheimer sandstone cores. The core temperature during formation was in the range of 0-4°C, depending on the experiment. Final hydrate saturations ranged from 0.40-0.64 which is consistent with previous experiments. The impact on growth patterns due to salinity variations was inspected by comparison with previous experiments with 0.1wt% NaCl. Salt lowers the water activity and shifts the hydrate stability line towards lower temperatures. A clear trend showed higher initial growth rate in the low salinity hydrate formations. The salinity of the formation water showed no clear correlation with the final hydrate saturation in the concentration range investigated. Pressure induced dissociation was conducted by 0.7bar pressure steps on 10 Bentheimer cores. There was an expected correlation between core temperature and dissociation pressure. The amount of gas released (2-12ml) on each pressure step was lower than expected and 8-12 pressure steps were needed to produce all the methane. Similar experiments previously conducted reached a ...
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