Natural gas density under extremely high pressure and high temperature: Comparison of molecular dynamics simulation with corresponding state model  

作　　者：Luchao Jin Yongming He Guobing Zhou Qiuhao Chang Liangliang Huang Xingru Wu 

机构地区：[1]Alchemy Sciences Inc.,6002 Rogerdale Rd,Ste 125,Houston,TX 77072,USA [2]College of Energy,Chengdu Science and Technology University,Chengdu 610059,China [3]University of Oklahoma,100 East Boyd st,Sarkeys Energy Center 1210,Norman,OK 73019,USA

出　　处：《Chinese Journal of Chemical Engineering》2021年第3期2-9,共8页中国化学工程学报（英文版）

基　　金：partial financial support from Ballard Petroleum Holdings and Yangtze University;the Schooner Supercomputing from the University of Oklahoma;the startup support from the University of Oklahoma。

摘　　要：This work applied molecular dynamics(MD)simulation to calculate densities of natural gas mixtures at extremely high pressure(>138 MPa)and high temperature(>200℃)conditions(x HPHT)to bridge the knowledge and technical gaps between experiments and classical theories.The experimental data are scarce at these conditions which are also out of assumptions for classical predictive correlations,such as the Dranchuk&Abou-Kassem(DAK)equation of state(EOS).Force fields of natural gas components were carefully chosen from literatures and the simulation results are validated with experimental data.The largest relative error is 2.67%for pure hydrocarbons,2.99%for C1/C3 mixture,7.85%for C1/C4 mixture,and 8.47%for pure H2S.These satisfactory predictions demonstrate that the MD simulation approach is reliable to predict natural-and acid-gases thermodynamic properties.The validated model is further used to generate data for the study of the EOS with pressure up to 276 MPa and temperature up to 573 K.Our results also reveal that the Dranchuk&Abou-Kassem(DAK)EOS is capable of predicting natural gas compressibility to a satisfactory accuracy at x HPHT conditions,which extends the confidence range of the DAK EOS.

关 键 词：High-pressure high temperature Z-factor Molecular dynamics simulation Natural gas density CORRELATIONS 

分 类 号：TE319[石油与天然气工程—油气田开发工程]