Experimental Investigation into the Production Behavior of Methane Hydrate under Methanol Injection in Quartz Sand

Abstract

In this work, the dissociation behavior of methane hydrate in quartz sand sediment by injecting a thermodynamic inhibitor, methanol (MeOH), was investigated using a one-dimensional experimental apparatus. The experimental results indicated that the hydrate dissociation process included four stages: free gas production, methanol dilution, major hydrate dissociation, and residual gas production. The overall liquid production rate was smaller than the injection rate during the whole production process. The cumulative gas produced from hydrate under methanol solution injection was adjusted with the reference experiment. A new strategy of the adjustment of the experimental runs was introduced, which was based on the ratio of the water and methanol solution injection rates. In general, with the increase of the methanol injection rate and the methanol concentration, the cumulative hydrate-originating gas produced increased. During the major hydrate dissociation stage, the production efficiency was enhanced continuously with the increase of the injection rate and concentration of the methanol solution, while the methanol efficiency increased and reached a maximum value when the concentration was 60 wt % and then gradually decreased.

Numerical Simulation of Hydrate Formation in the LArge-Scale Reservoir Simulator (LARS)

“…From micro-to macro-scale, various laboratory experimental devices [3,[12][13][14][15][16][17][18][19][20][21][22][23][24][25] combined with state-of-the-art monitoring equipment [18,[26][27][28][29][30][31][32], have been developed to investigate gas hydrate formation processes based on different hypotheses and to determine the optimum parameters for hydrate production. Evidently, it is impractical and challenging to extract intact and undisturbed NGH samples from hydrate-bearing layers.…”

Influence of Water Saturation, Grain Size of Quartz Sand and Hydrate-Former on the Gas Hydrate Formation

“…At the same time, natural gas as a fuel is much more environmentally friendly than coal and oil since it has a high calorific value; when it is burned, only carbon dioxide and water are formed [9,15]. Four main methods of gas hydrate field development have been proposed [16]: depression [17,18], heating [19,20], injection of inhibitors [21][22][23], and replacement with carbon dioxide [24,25]. In this regard, the study of the formation and decomposition of gas hydrates in porous media is a key point for a fundamental understanding of natural gas hydrates' behavior, the development of technologies for their extraction and practical application in the processes of transportation and storage.…”

Key Areas of Gas Hydrates Study: Review

“…Chen et al [45] showed that the thermal stimulation method (hot water injection) yields gaseous methane at a During depressurization [41,42,[118][119][120], when the operating pressure falls below the equilibrium pressure, the ambient heat is absorbed to dissociate hydrates into gas and water [97]. The production of gas during the depressurization of methane hydrate reservoirs can be divided into three stages (free gas, mixed gas, and gas from dissociated methane hydrate) [125]. During depressurization, no artificial heat is supplied.…”