Polyether Anti-Emulsification Agents for Heavy Oil W/O Emulsion Inhibition: Structural Screening, Performance Evaluation, and Orthogonal Optimization

In the middle and late stages of oilfield development, increased water cut and pipeline shear promote stable W/O emulsions, raising viscosity, gathering and transportation friction, and energy consumption; traditional “heating + light oil blending” is energy-intensive and limited by light-oil resources, making chemical emulsification inhibition and drag reduction important. This study used field heavy oil produced fluid to develop suitable anti-emulsification agents. Physicochemical tests per industry standards analyzed component composition, carbon number distribution, density–temperature characteristics, and viscosity–temperature rheology to reveal the material basis for easy emulsification and thickening. Using water separation percentage and rate, oil–water interfacial morphology, produced water quality, and interfacial tension as indicators, bottle tests screened single agents from 11 structural types; temperature and dosage effects were investigated, and a three-factor three-level orthogonal experiment quantified factor weights. The heavy oil was enriched in asphaltenes, had an imbalanced resin-to-asphaltene ratio, and contained relatively high-carbon-number hydrocarbons. Multi-branched polyether agents performed significantly better than linear polyether and inorganic salt agents. Temperature was dominant, followed by agent type; dosage was weakest. These results clarify the heavy oil’s properties and single-agent action patterns and provide data and a theoretical basis for formulation optimization and process parameter determination for emulsification-inhibiting and drag-reducing gathering and transportation.