Correlations of Characteristics of Saskatchewan Crude Oils/Asphaltenes with Their Asphaltenes Precipitation Behavior and Inhibition Mechanisms: Differences between CO2- and n-Heptane-Induced Asphaltene Precipitation

Abstract

The structural and molecular characteristics of the asphaltenes of four oilslight oil, L-O; medium oils, M1-O and M2-O; and heavy oil, H-Ofrom the Weyburn and adjacent areas in Saskatchewan, Canada were determined and correlated with the oils' asphaltene precipitation behavior and mechanism, as well as their chemical inhibitor effectiveness, for the purpose of determining differences between CO2 and hydrocarbon flooding for enhanced oil recovery (EOR). A multitechnique approach involving Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, 13C NMR spectroscopy, gated spin−echo (GASPE) spectroscopy, inductively coupled plasma (ICP), elemental analysis, saturates−aromatics−resins−asphaltenes (SARA) analysis, molecular weight, and density studies was used for characterization of the crude oils and their n-heptane-derived asphaltenes. Results showed that the asphaltene precipitation behavior and mechanism each were strong functions of the oil and asphaltene ...