Molecular dynamics simulation of methane hydrate dissociation by thermal stimulation in conjunction with chemical injection method

The characteristics of methane hydrate dissociation in the presence of thermal stimulation, chemical injection, and thermal stimulation in conjunction with chemical injection method were investigated by molecular dynamics simulation. The effect of the injection of liquid water (WTR) and 30 wt% ethylene glycol (EG) solution at 277 K and 340 K on methane hydrate dissociation was studied. The results showed the hydrogen bonds between WTR molecules and the water molecules on the hydrate surface were formed,which destroyed the original hydrogen bond balance of the hydrate. Therefore, the clathrate structure of hydrate collapsed, and the hydrate dissociated. The hydrogen bonds was formed obviously between hydroxyl groups of EG molecules and the water molecules on the hydrate surface; this caused the original stable clathrate structure of the hydrate to be destroyed and collapse, and, furthermore, promoted the dissociation of the methane hydrate and the release of methane gas. Compared with the effects of injecting WTR and 30 wt% EG solution at 277 K and 340 K on the dissociation of methane hydrate, the effectivences was found to be: EG (340 K) > WTR (340 K) > EG (277K) > WTR (277K). The thermal stimulation in conjunction with chemical injection method can more effectively promote the dissociation of hydrate.