关键词: 沥青质, 沉淀, 模型, 相平衡, 计算

Abstract:

When the temperature，pressure and the components of the crude oil system change，the asphaltenes will be continuously
precipitated as a solid phase from the liquid phase，then flocculated and deposited onto the wall. Sometimes，severe
deposition problems can block up the operation of wellbore and transportation pipelines. The crude petroleum of the gas-liquidsolid
three phase equilibrium must be studied in order to accurately describe the equilibrium and precipitation process in oil
and gas system which including asphaltene and other organic polymer solid compositions. The characterization of oil and gas
system containing asphaltenes and the calculation of three phase equilibrium are studied，a method which changes three phase
equilibrium calculation into two phase equilibrium calculation is proposed on the assumption that the asphaltene precipitation
does not affect the gas–liquid balance. Though these assumptions，liquid–solid(asphaltene) phase equilibrium is calculated on
the basis of the results of gas–liquid phase equilibrium calculation. Based on the analysis，this article assumes asphaltene is a
solid phase，and develops a gas–liquid–solid phase equilibrium thermodynamic model to simulate the asphaltene precipitation
in gas–liquid–solid phase equilibrium system. This model can consider the effect of standard temperature and standard pressure
on the solid asphaltene fugacity calculation. The results of actual application show that this model is effective to be used to
simulate and calculate the phase envelope and amount of solid asphaltenes in a crude system contained oil and gas.

Key words: asphaltene, precipitation, model, phase equilibrium, calculation