Hydrate formation in near surface ocean sediments

The aims of this research project were to assist in understanding hydrate formation, stability, and scientific aspects of CO2 storage as a liquid and CO2 hydrate. These have been addressed by two investigatory pathways: hydrate stability modelling and hydrate formation within sediments (in synthetic CO2 hydrates and natural methane hydrates). Developed computer models predict large regions offshore Western Europe with the potential to store considerable volumes of CO2 as a hydrate. Laboratory experiments have also shown CO2 hydrate to form rapidly and relatively easily in sandy sediments, cementing the sediment grains. In water-rich environments hydrate appears to create pore-filling cement impeding further CO2 flow to underlying sediments, which may aid trapping of an underlying liquid store. Fortunate acquisition of natural hydrate cores from Cascadia Margin also allowed investigation of natural methane hydrate formation; revealing a number of well-preserved methane hydrate morphologies, and complex brine filled pore networks within the hydrate, resulting from different rates of growth. Results highlight a number of research areas, which need addressing through further investigations. However, these preliminary investigations support CO2 storage as a hydrate as a potential feasible storage method, and this method should be pursued further as an emissions reducing mitigation strategy.