Petroleum Reservoir Evaluation and Development ›› 2022, Vol. 12 ›› Issue (5): 825-832.doi: 10.13809/j.cnki.cn32-1825/te.2022.05.015

• Comprehensive Research • Previous Articles    

Structural characteristics and gas storage properties of gas hydrates based on molecular simulation

XIANG Xueni1(),HUANG Liang1(),ZHOU Wen1,ZOU Jie1,ZHANG Zhuoya2   

  1. 1. College of Energy, Chengdu University of Technology, Chengdu, Sichuan 610059, China
    2. State Key Laboratory of Heavy Oil Processing, China University of Petroleum(Beijing), Beijing 102249, China
  • Received:2021-11-08 Online:2022-09-27 Published:2022-10-26
  • Contact: HUANG Liang E-mail:462092559@qq.com;huangliang@cdut.edu.cn

Abstract:

Natural gas hydrate are rich, which is one of the most potential new energy resources with abundant resources. However, gas hydrate has not been exploited commercially at present, and its micro-structure characteristics and gas storage mechanism need to be clarified urgently. Based on the framework and guest molecular information of SI, SII and SH type gas hydrates, the molecular models of three typical gas hydrates are constructed and optimized. The hydrogen bonds number, hydrogen bonds length, porosity, pore composition, pore size distribution and other structural characteristics of hydrates are determined by structural characterization, and the micro-structure differences of three typical hydrates are compared and analyzed. Based on the hydrate skeleton structure, the adsorption behavior of methane and carbon dioxide is studied by the grand Canonical Monte Carlo method. Combined with the adsorption capacity and adsorption heat, the gas storage characteristics and differences of the three hydrates are clarified. The results show that the hydrogen bonds in SII hydrate are the longest and the most abundant, but the pore connectivity is the worst. High pressure is conducive to increasing the gas storage capacity of hydrate, while low temperature can increase the stability of gas adsorption in hydrate. Although the amount of carbon dioxide storage is smaller than that of methane, the adsorption stability of carbon dioxide is stronger. The adsorption capacity of gas in SII type hydrate is the largest, and the adsorption heat in SI type hydrate is the largest.

Key words: gas hydrate, structural characteristics, gas storage properties, adsorption, molecular simulation

CLC Number: 

  • TE311