Microscopic Mechanism and Fluctuation-Dissipation of Methane Hydrate Decomposition in Oil-Containing Systems.

Area of Science:

• Petroleum Engineering
• Physical Chemistry
• Materials Science

Background:

• Hydrate blockages in oil and gas pipelines pose significant risks to transportation safety and operational efficiency.
• Clarifying hydrate decomposition mechanisms is crucial for mitigating these risks and ensuring reliable energy transport.

Purpose of the Study:

• To investigate the microscopic decomposition mechanisms of methane hydrates within oil-containing systems.
• To elucidate the influence of crude oil molecular structure on hydrate decomposition kinetics and thermodynamics.

Main Methods:

• Construction of four molecular models representing alkanes, aromatics, and asphaltenes.
• Application of multiparameter analysis, Green-Kubo, and fluctuation-dissipation frameworks.
• Examination of decomposition from kinetic, rheological, and energetic perspectives.

Main Results:

• Oil molecular structure significantly regulates hydrate decomposition rates; light oils accelerate it, while heavy oils inhibit it.
• Heavy oil systems display increased dynamic instability and higher dissipation coefficients during guest release.
• Analysis of van der Waals, electrostatic, and hydrogen bond dynamics reveals energy-driven decomposition differences.

Conclusions:

• The molecular structure of oil plays a critical role in modulating hydrate decomposition.
• Quantified fluctuation-dissipation characteristics provide insights into hydrate stability in complex oil environments.
• Established a molecular-scale foundation for understanding and predicting hydrate behavior in oil-based systems.