(411c) Natural Gas Hydrates in Marine Locations: Effect of Stimulation Temperature on Gas and Water Production

Natural gas (NG) is the cleanest burning fossil fuel, generating the least amount of CO₂ per unit energy produced. Following the growing energy demand and the depletion of conventional energy resources, there is a need to harness energy from the unconventional sources, such as shale gas and natural gas hydrates (NGH). The total carbon content sequestered in NGH is of the order of 10,000 Gt C, more than twice of the conventional fossil fuels (gas, oil and coal) combined. In this work, we introduce a new approach to determine the fractional conversion of methane under an excess water environment to mimic marine locations, which is found to be around 81.5%. We further investigated the gas and water production profiles from the hydrate bearing sediments. The dissociation of methane hydrate was done under a constant bottom-hole pressure of 4.5 MPa subjecting to different thermal stimulation ranging from 278.7 K to 285.2 K. It was found that a low temperature driving force would result in an extremely low dissociation rate shedding light on impact of global warming on the stability of hydrates in nature, and a minimum temperature of 280.7 K (corresponding to 2.1 K temperature driving force) is required to achieve 90% dissociation within 10 hours. The importance of water management in developing efficient methods to effectively recover energy from hydrate bearing sediment will be presented.