基于PR状态方程的粘度模型

基于p-v-T和T-μ-p图形的相似性。结合两参数Peng-Robison状态方程,建立了一个能够同时预测流体气、液相粘度的统一模型。该模型的特点是能够同时描述气、液相及超临界流体的粘度随温度、压力和组成的变化,并能够连续通过临界点。在宽广的温度、压力范围内,对22种烷烃及二氧化碳、氮气共计4250个数据点的粘度进行了计算,绝对平均误差为7.01%;通过引入vanderWals单流体混合规则,将PR粘度模型应用于明确烃类混合物及油气藏流体粘度的计算。三个二元烃类混合物2441个数据点的绝对平均误差为15.71%;9种天然气及22种油藏原油粘度计算值的绝对平均误差分别为9.8%和13.99%,计算结果优于现有的油气藏流体粘度模型。

THE VISCOSITY MODEL BASED ON PR EQUATION OF STATE

A unified viscosity model is developed to predict the viscosity of both gases and liquids simultaneously based on the similarity between PVT and TP,and the combination of PengRobinson equation of state.The features of the model is that it can describe both gases, liquids and super critical viscosity with changes of temperature,pressure,composition,as well as go through the critical point.The overall average absolute error is 7.01% when 4250 data points in total like 22 hydrocarbons,carbon dioxide and nitrogen have been calculated under broad scopes of temperature and pressure.By using the van der Waals one fluid mixing rule for the EOS parameters of mixture,the viscosity model based on two parameters PengRobinson EOS is utilized to predict the viscosity of mixtures.The absolute average error is 15.71% for 2441 data points concerning three binary hydrocarbon mixtures(methane/ndecane;methane/propane;methane/nbutane),while 9.8% and 13.99% for calculation values of nine natural gases and 22 reservoir crude viscosity respectively,with the calculation results superior to the existing viscosity model for oil and gas reservoir fluids.