Wayne D. Monnery

A review of practical calculation methods for the viscosity of liquid hydrocarbons and their mixtures

This paper reviews methods for the prediction and correlation of Newtonian viscosity for pure components and mixtures of liquid hydrocarbons and petroleum fluids, which are suited for practical engineering use. The methods reviewed were chosen because they are well known and accepted or appear potentially promising. The methods are categorized as semi-theoretical or empirical and further distinguished as predictive or correlative. The applicability and average deviations for each method are discussed, with the recommended methods identified.

Viscosity prediction from a modified square well intermolecular potential model

A statistical mechanical based model for simultaneously calculating liquid and gas phase viscosities using the square well intermolecular potential has been developed. Theoretical results are utilized along with modifications to correct the model for the molecular chaos assumption and the inadequacy of the square well potential. The radial distribution function values are determined from perturbation theory. Model parameters are obtained from liquid and gas viscosity data and generalized with group contributions. With the resulting model, liquid and gas viscosities of a variety of nonpolar compounds are correlated within 5% and 3%, respectively, and predicted within 8% and 5%, respectively.

Viscosity prediction from a modified square well intermolecular potential model: polar and associating compounds

A theoretically based model for calculating both liquid and gas phase viscosities has been developed by modifying a statistical mechanics viscosity model based on the square well intermolecular potential. The original theory was corrected to account for the assumptions of only two-body interactions and molecular chaos for velocities and the inadequacy of the square well potential. In addition, the model was modified so that it approaches a consistent low density limit and to improve the dilute gas temperature dependence. The three model parameters are obtained from gas and liquid viscosity data and generalized with group contributions. With the resulting modified square well viscosity model, gas and liquid viscosities for a wide variety of over 100 polar and hydrogen bonding compounds are correlated with average deviations of 0.4% (gas) and 2.1% (liquid), and predicted with average deviations of 2.1% (gas) and 6.8% (liquid).

Computational Fluid Dynamics-Based Study of an Oilfield Separator--Part I: A Realistic Simulation

Summary A realistic computational fluid dynamics (CFD) simulation of a field three-phase separator has been developed. This realistic CFD simulation provides an understanding of both the microscopic and macroscopic features of the three-phase separation phenomenon. For simulation purposes, an efficient combination of two multiphase models of the commercial CFD software, Fluent 6.3.26 (ANSYS 2006a), was implemented. The flow-distributing baffles and wire mesh demister were also modeled using the porous media model. Furthermore, a useful approach to estimating the particle size distribution in oilfield separators was developed. The simulated fluid-flow profiles are realistic and the predicted separation efficiencies are consistent with oilfield experience.