Change of the chemical and physical properties of heavy oil before and after CO₂ treatment

ABSTRACT

In order to improve the heavy oil displacement effect by CO₂ flooding, the change of the chemical and physical properties of heavy oil before and after CO₂ treatment is systematically investigated by indoor simulation experiment. Experimental results show that CO₂ treatment can decrease the amount of the saturates but increase that of the aromatics, and yet has little impact on those of resins and asphaltenes. Besides, the corresponding consequence is that there has an increase in the viscosity of the heavy oil and the particle size of the asphaltene micelle, and a decrease in the conductivity of the heavy oil and n-heptane systems and the stability of the asphaltene micelle after CO₂ treatment. The conclusions can provide a certain guidance for high-efficiency development of heavy oil reservoir by CO₂ flooding.

KEYWORDS:

• asphaltene
• composition
• CO₂ treatment
• heavy oil
• physicochemical property

Funding

This study was supported by the Fundamental Research Funds for the Central Universities (16CX02020A) and the National Natural Science Funds (51504215).