多孔介质中天然气水合物分解热力学模型研究

Thermodynamic Model of Natural Gas Hydrate Dissociation Conditions in Porous Media

天然气水合物具有能量密度高、分布广、规模大、埋藏浅、成藏物化条件优越等特点,是21世纪继常规石油和天然气能源之后最具开发潜力的替代能源。多孔介质中天然气水合物的分解热力学是目前研究的热点和难点问题。本文采用VPT状态方程计算流动相的逸度,采用改进Vander Waalsand Platteeuw模型计算水合物相态。同时,考虑毛细管力对相态逸度的影响,引入修正项改进了模型,并运用改进模型对CH4和CO2水合物相平衡分解条件进行预测,其预测结果和实验结果比较符合。

The natural gas hydrate is the most hopeful clean energy substituting traditional energy such as oil and natural gas in 21st century,characterized by high density of energy,broad distribution,large scale,shallow burying and good physicochemical conditions for accumulation.The natural gas hydrate will play an important strategic role in the energy structure in the future,and the thermodynamic model of natural gas hydrate dissociation conditions has been a heated topic recently.In the paper,the fugacity in fluid phases was caculated by using the VPT EoE model,while the phases of natural gas was caculated by using the improved Vander Waalsand Platteeuw model.In order to account for capillary pressure effects on the fugacity of gas hydrate phase,a correction of the model was suggested.Good agreement between the model predictions and the experimental data was obtained.