Demulsification of Fluids Produced from Polymer Flooding in Oilfields: A Molecular Dynamics Simulation Study

Area of Science:

• Petroleum Engineering
• Colloid and Surface Science
• Materials Science

Background:

• Heavy oil recovery often involves polymer flooding, generating stable oil-in-water emulsions.
• Effective demulsification is crucial for separating oil and water post-extraction.
• Partially hydrolyzed polyacrylamide (HPAM) is commonly used but complicates demulsification.

Purpose of the Study:

• To compare the demulsification performance of two distinct demulsifiers (Demulsifier X and Y).
• To elucidate the microscopic mechanisms governing demulsification at the oil-water interface.
• To provide experimental validation for demulsifier selection in heavy oil processing.

Main Methods:

• Molecular dynamics (MD) simulations of demulsifier interactions with heavy oil, water, and HPAM.
• Construction of molecular models using BIOVIA Materials Studio.
• Experimental bottle tests evaluating dehydration rates and oil content under varying conditions (time, temperature, concentration).

Main Results:

• MD simulations revealed demulsifiers displace HPAM, increase interfacial tension, and reduce interfacial energy.
• Demulsifier Y demonstrated superior performance compared to Demulsifier X.
• Demulsifier Y achieved higher dehydration rates with lower dosage, shorter settling times, and lower temperature requirements.

Conclusions:

• Demulsifier Y is more effective for demulsifying polymer-containing heavy oil emulsions.
• The study provides mechanistic insights into demulsifier action at the molecular level.
• Findings support the rational design and application of efficient demulsifiers in the petroleum industry.