Low-Temperature Rheological Behavior and Wax Deposition Control in High-Paraffin Blended Crude Oils Using Chemical Additives

A. V. Gasimzade and V. K. Nurullayev

Abstract
This study investigates the low-temperature rheological behavior and wax deposition tendency of high-paraffin blended crude oil in order to improve flow stability during pipeline transportation. The results show that decreasing temperature leads to a significant increase in yield stress and effective viscosity, indicating the formation of a structured paraffin network responsible for reduced flowability. Comparative analysis demonstrated that the Herschel–Bulkley model most accurately describes the non-Newtonian behavior of the system (R² = 0.995). Strong correlations between pour point, yield stress, and consistency index confirm the structural origin of flow resistance and highlight the role of crystallization processes in determining rheological properties. Chemical treatment significantly weakened intermolecular interactions within the paraffin–resin–asphaltene system, reduced wax deposition tendency, and improved flow characteristics. Among the investigated formulations, the composite additive (DHC) exhibited the highest efficiency, promoting partial transition toward near-Newtonian behavior and enhanced low-temperature mobility. The results demonstrate that composite chemical additives provide an effective approach for controlling structure formation and improving transportation properties of high-paraffin crude oils.

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Keywords
rheology, yield stress, wax deposition, flow behavior index, chemical additives