甲烷、二氧化碳和氮气在油相中溶解度的预测模型

Forecasting model of solubility of CH,CO and N in crude oil

薛海涛 卢双舫 付晓泰

Xue Haitao Lu Shuangfang Fu Xiaotai

以甲烷、二氧化碳、氮气在原油中的溶解度实验为基础,观察3种气体在原油中的溶解特征和规律,并从理论上探讨了气体在原油中的溶解机理,提出以下观点:1)原油中的烃类物质在气体溶解过程中起主要作用,而胶质、沥青质等大分子对气体溶解度的贡献很小;2)气体分子可与烃类物质分子形成加合物分子,这个过程可看成是一个表观化学反应,其反应程度可以用一个平衡常数来描述;3)先期形成的气体-烃加合物分子对后续的气体还具有一定的溶解能力,这种再溶解能力可以用一个二次作用系数α来描述;4)原油的性质用地面原油的密度、原油中烃的质量分数和烃的平均分子量来表征。在此基础上,综合考虑影响气体溶解的其他因素,推导出气体在原油中的摩尔溶解度理论方程和气油比的理论方程。经与实验数据对比,理论计算值与实验结果有很好的一致性。

Dissolution characteristics and mechanisms of CH,CO and N in crude oil are studied through solubility experiments,resulting in the following understandings: ① hydrocarbons play a key role in the process of gas dissolution in crude oil,while macromolecular substances,such as colloid and asphaltene,have a little influences on the gas solubility.② Gas molecules and macromolecular substances in crude oil can form adduct molecules;this process can be treated as an apparent chemical reaction and its reaction degree can be described by an equilibrium constant .③ Early formed gas-hydrocarbon adduct molecules have certain solvency to subsequently formed gas molecules,which can be described by a secondary dissolving coefficient α.④ Physical properties of crude oil can be characterized by the density(ρ) of surface crude oil and the mass fraction(x) and average molecular weight() of hydrocarbons in crude oil.Combined with other factors that have influences on gas dissolution,the theoretical equation of gas'mole solubility in crude oil and that of gas-oil ratio in crude oil are derived.Comparison with experimental data shows that calculated and measured values have a good consistency.

10.11743/ogg20050408