Shuxia Li

Dissociation of Methane Hydrate by Hot Brine

Natural gas hydrate has been regarded as a potentially unconventional natural gas resource. It is widely distributed in the world. Many methods are proposed to dissociate hydrate, among which heat injection is one of the most effective ones. So, the investigation of production performance under different heat injection modes provides theoretical basis for actual hydrate production. An experimental study on hydrate dissociation and gas production behavior by hot brine injection was conducted with a self-designed 2D sand-packed system. Two patterns of heat injection (continuous heat injection and intermittent heat injection) are studied and the gas production, water production, and temperature variation are analyzed. Results show that the gas produced by continuous heat injection is notably more than that by intermittent heat injection; with the same heat injected, the temperature variation of continues heat injection is larger than that of intermittent heat injection; during the process of heat injection, the water production rate is slightly larger than that of water injection, which is mainly influenced by water injection rate, heat injection patterns and water production from hydrate dissociation. Under the conditions of experiment, the result of continuous heat injection is superior than that of intermittent heat injection.

Hot-brine Injection for the Dissociation of Natural Gas Hydrates

A new one-dimensional experimental system for natural gas hydrate (NGH) exploitation is designed, which is used to study the formation and dissociation processes of NGH. NGH is formed in the sand-packing tube, and then hot-brine is injected into the tube to study the thermal dissociation characteristics. The injection parameters that influence gas production rate and energy efficiency are analyzed. The results show that the higher the injection temperature and injection rate are, the higher the gas production rate is. In addition, the most sensitive parameter, which influences the energy efficiency of thermal stimulation is the hot-brine temperature, followed by the hot-brine injection rate and injection time. This study provides an experimental basis for further study on NGH exploitation in the future.