Prediction the Wax Precipitation Characteristics in Waxy Crude Oil with Heavy Fraction Characterization

The calculation of component content distribution and related basic physical parameters in the heavy fraction of waxy oil will affect the calculation results of thermodynamic phase equilibrium and have an important impact on the prediction of the final wax precipitation characteristic parameters. Aiming at the problem that conventional separation models are not suitable for waxy oil with high content of heavy components, this paper compares and analysis the classical Ahmed model, Hosein model, Pengyang model, Katz model and Pedersen model, and points out that Hosein model has the highest precision. Based on the Hosein model, Hosseini Far-Jamhidi is used to calculate the physical properties of the separated SCN components, Whitson's formula is used to merge the separated virtual components, and Hong mixing rule is used to calculate the physical parameters of the merged virtual components. The prediction results of wax precipitation characteristics of each oil sample with or without characterization of heavy fraction are analyzed by PVT-Sim, which verifies the importance of heavy fraction characterization to improve the prediction accuracy of wax precipitation characteristics of waxy crude oil.