Analysis of Xinjiang asphaltenes using high precision spectroscopy

Area of Science:

• Petroleum Geochemistry
• Analytical Chemistry

Background:

• Asphaltenes cause significant flow assurance issues in oil production.
• Developing cost-effective and environmentally friendly inhibitors is crucial.

Purpose of the Study:

• To perform a comparative spectroscopic analysis of Xinjiang heavy oil asphaltenes.
• To predict the internal morphology and structure of these asphaltenes.
• To inform the development of novel chemical inhibitors.

Main Methods:

• Fourier Transform Infrared Spectroscopy (FTIR)
• Proton-Nuclear Magnetic Resonance (H-NMR)
• Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FTICR-MS)
• Comparative analysis with Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM) data.

Main Results:

• Asphaltenes are polycyclic and aromatic, containing heteroatoms and metals.
• Identified 13 basic and 11 non-basic/acidic nitrogen compounds within the aromatic network.
• Mass distribution of asphaltenes ranges from 100-800 Da.
• FTIR and H-NMR identified functional groups like ethers, sulfides, amides, and sulfoxides.
• Structural parameters such as aromaticity and degree of unsaturation were determined.

Conclusions:

• The characterized Xinjiang asphaltenes are consistent with "island" and "aryl linked core" structural models.
• The detailed structural insights support the ongoing research for effective chemical inhibitors.