This paper investigates the role of oil aromaticity in mis-cibility development and in the deposition of heavy hydrocarbons during CO2 flooding. The results of phase equilibrium measurements, compositional studies, sand-pack displacements, and consolidated corefloods are presented. Reservoir oil from the Brookhaven field and synthetic oils that model natural oil phase behavior are examined.

Phase compositional analyses of CO2/synthetic-oil mixtures in static PVT tests demonstrate that increased oil aromaticity correlates with improved hydrocarbon extraction into a CO2-rich phase. The results of tertiary corefloods performed ,with the synthetic oils show that CO2-flood oil displacement efficiency is also improved for the oil with higher aromatic content. These oil aromaticity influences are favorable.

Reservoir oil experiments show that a significant deposition of aromatic hydrocarbon material occurs when CO2 contacts highly asphaltic crude. Solid-phase formation was observed in phase equilibrium and displacement studies and led to severe plugging during linear flow through Berea cores. It is unclear how this solid phase will affect oil recovery on a reservoir scale.

Keywords:
hydrocarbon, upstream oil & gas, enhanced recovery, coreflood, chemical flooding methods, saturation, liquid phase, co 2, sandpack, pvt measurement
Subjects:
Chemical flooding methods, Fluid Characterization, Improved and Enhanced Recovery, Phase behavior and PVT measurements
Copyright 1985, Society of Petroleum Engineers
You can access this article if you purchase or spend a download.