含沥青质原油体系在温度、压力或成分等发生变化时，沥青质会不断地沉淀、聚集并依附于管壁，严重时会堵塞油井和外输管道。要准确地描述沥青的沉淀和沉积问题，需要对原油体系气-液-固三相相平衡进行研究。通过调研和分析含沥青质油气体系特征过程和三相相平衡计算方法，在假设沥青质的沉淀不影响体系气-液平衡的基础上，提出先计算气-液平衡，利用气-液平衡计算出的结果进一步计算液-固平衡，将三相平衡计算分解成两次两相平衡计算。将沉淀的沥青质视为固相，建立了一种用以模拟沥青质沉淀的气-液-固三相相平衡热力学模型，同时考虑了标准态温度和压力对沥青质固相逸度计算的影响。某一含气原油中沥青质沉淀计算结果表明，该模型能够有效地模拟并计算油气体系中沥青质沉淀量和包络线。%When the temperature,pressure and the components of the crude oil system change,the asphaltenes will be con-tinuously 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-liquid-solid 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
展开▼
