• Molecular dynamics simulations reveal that EVA disrupts ordered wax crystallization by adopting a curly conformation due to polar VA side chains, delaying wax solidification.
• EVA exhibits a dual effect on hydrate formation: its nonpolar backbone enhances methane diffusion to wax surfaces (inhibiting hydrates), while VA chains repel methane, increasing local methane concentration and promoting hydrate nucleation.
• The net impact of EVA on hydrate formation depends on wax crystal size: inhibition dominates for small crystals, promotion for larger crystals.
• EVA effectively mitigates both wax and hydrate deposition in low-wax-content multiphase systems, offering a promising strategy for deep-sea flow assurance.