Insights into Flow Improving for Waxy Crude Oil Doped with EVA/SiO₂ Nanohybrids

Area of Science:

• Materials Science
• Petroleum Engineering
• Colloid and Surface Chemistry

Background:

• Wax deposition in crude oil pipelines is a significant challenge, impacting flow assurance and transportation.
• Understanding the mechanisms of wax crystallization and rheological modification is crucial for developing effective flow improvers.

Purpose of the Study:

• To investigate the effects of ethylene vinyl acetate (EVA) and EVA/SiO2 nanohybrids on wax crystallization and rheological behavior of waxy crude oil.
• To elucidate the mechanisms by which nanohybrids inhibit wax deposition and improve oil fluidity.

Main Methods:

• Differential scanning calorimetry (DSC) to determine wax appearance temperature.
• Thermo X-ray diffraction (XRD) to analyze wax crystal structure and index.
• Polarized optical microscopy (POM) to observe wax crystal morphology.
• Rheological tests to evaluate changes in viscosity, inflection point, and yield stress.

Main Results:

• SiO2 nanoparticles enhanced EVA's ability to lower the wax appearance temperature.
• EVA/SiO2 nanohybrids reduced the overall wax crystal index and altered crystal grain sizes.
• Nanohybrids acted as nucleation sites, adsorbing asphaltenes and resins to inhibit wax crystal formation.
• Nanohybrids demonstrated superior performance over EVA in reducing viscosity and yield stress.

Conclusions:

• EVA/SiO2 nanohybrids are effective in inhibiting wax deposition and improving the rheological properties of waxy crude oil.
• The study provides insights into the flow improvement mechanisms of nanohybrid materials.
• Findings offer guidance for designing advanced wax inhibitors for enhanced oil transportation and flow assurance.