Analyzing the Process of Gas Production from Methane Hydrate via Nitrogen Injection
2017
Zhang, Lunxiang | Kuang, Yangmin | Zhang, Xiaotong | Song, Yongchen | Liu, Yu | Zhao, Jiafei
The application of air or nitrogen injection to extract natural gas from hydrates has attracted considerable attention because air and nitrogen are abundant; however, few studies have considered the relatively new method. This study employed magnetic resonance imaging to investigate the characteristics of hydrate dissociation via N₂ injection. The results show that methane hydrate dissociation using N₂ injection can be divided into three main stages: free gas and water liberation, hydrate dissociation driven by chemical potential differences, and restriction of hydrate dissociation due to increased resistance to N₂ diffusion and a decreased contact area between N₂ and hydrate. Various factors associated with the N₂ injection method were considered, including injection rate and hydrate saturation. Furthermore, a comparison of recovery:injection ratio and methane cumulative production ratio to the results of hydrate dissociation via depressurization suggests that during low-hydrate saturation exploitation, N₂ injection has advantages over the depressurization method.
显示更多 [+] 显示较少 [-]