压力变化对Ⅰ型甲烷水合物稳定性影响的分子动力学模拟  

Molecular Dynamics Simulation of Influence of Pressure Change on SI Methane Hydrate Stability

作　　者：段小龙[1] 任红[2] 高光海[1] 许俊良[2] 仇性启[1] 

机构地区：[1]中国石油大学(华东)化学工程学院,山东青岛266580 [2]中国石化胜利石油管理局钻井工艺研究院,山东东营257017

出　　处：《石油化工》2014年第6期657-661,共5页Petrochemical Technology

基　　金：国家科技重大专项"天然气水合物勘查与试采工程"(GZH201200602);中国石油大学(华东)研究生创新工程资助项目(YCX2014021)

摘　　要：采用分子动力学方法模拟了压力变化对Ⅰ型甲烷水合物稳定性的影响规律,通过对体系构象、径向分布函数、势能变化和均方位移等参数进行分析,从微观水平揭示了Ⅰ型甲烷水合物降压分解机理。模拟结果表明,压力越低,体系稳定后的势能越大,水合物越不稳定;氧原子径向分布函数的特征峰值随压力的降低而减小,展宽变宽,水分子排列有序性下降;体系压力较高时,氧原子和碳原子的均方位移稳定在略大于零的某一数值,体系压力降至10 MPa时,氧原子和碳原子的均方位移曲线在模拟的最后阶段趋于直线。The influence of pressure change on SI methane hydrate stability was investigated by molecular dynamics simulation.The results indicated that,the potential energy of the hydrate system increased and the system became unstable with the decrease of pressure.The peak value and width of the radius distribution function（RDF） of oxygen atoms decreased and broaden with the decrease of the pressure respectively,which indicated that the order of the water molecule permutation weakened.The mean square displacements（MSDs） of the oxygen and carbon atoms were stable at certain values more than zero under considerable pressure.The MSD curves of the oxygen and carbon atoms approached to straight lines in the final stage of the simulation when the pressure decreased to 10 MPa.The decomposition mechanism of the SI methane hydrate was proposed by the analysis of the structure,RDF,potential energy and MSD of the system.

关 键 词：甲烷水合物 模拟 分子动力学 

分 类 号：TQ013.1[化学工程]