Abstract
Natural gas hydrate is regarded as a potential energy resource in the future. Although it is well known that hydrate dissociation produces both gas and water, it is still unclear how gas and water are produced from hydrate bearing sediment in response to different production strategies. While a large body of literature have focused on elucidating the effect of production conditions (e.g. pressure, temperature) on the dissociation behaviour from hydrate reservoirs, limited effort has been paid in investigating how gas and water production can be simultaneously controlled through process design (e.g. the incorporation of wellbore, wellbore design).
In this study, the effect of a single horizontal wellbore on gas and water production from water saturated hydrate bearing sediments of 40% hydrate saturation (SH) was evaluated by a comparison with the base case (without wellbore) in a 980 mL crystallizer at a bottom hole pressure (BHP) of 3.5 MPa. Distinctive production behaviour, in terms of temperature, gas and water production kinetics, was observed in each production configuration. We have demonstrated an improvement of ~ 15% in gas production through the addition of horizontal wellbore in the current system. Even more so, water production was found to be reduced significantly (~ 50%) through the incorporation of horizontal wellbore. This finding revealed opportunities in future research to develop technology that enable simultaneouos enhancement of gas production and mitigation of water production during hydrate recovery.