Effects of polymers as direct CO₂ thickeners on the mutual interactions between a light crude oil and CO₂

In this paper, two commercial polymers with relatively low molecular weights, poly vinyl ethyl ether (PVEE) and poly 1-decene (P-1-D), are tested as direct thickeners for CO₂ and their detailed effects on the mutual interactions between a light crude oil and polymer-thickened CO₂ are experimentally studied under different reservoir pressures. More specifically, the polymer cloud-point pressures are measured at different known polymer solubilities in supercritical CO₂. The equilibrium interfacial tensions (IFTs) and onset pressures of quick polymer dissolution into CO₂ are measured for the polymer−pure CO₂ systems. The polymer-swelling effect due to pure CO₂ dissolution is observed and examined. To study the mutual interactions between the light crude oil and polymer-thickened CO₂, their equilibrium IFTs are measured and their so-called minimum miscibility pressures (MMPs) and onset pressures of the initial quick light-hydrocarbons extraction by CO₂ are determined. The oil-swelling effect due to polymer-thickened CO₂ dissolution is also visualized and analyzed. All the experimental data for polymer-thickened CO₂ are compared with those for pure CO₂.