Effect of Polyethylene-Vinyl Acetate Pour Point Depressants on the Flow Behavior of Degassed Changqing Waxy Crude Oil before/after scCO2 Extraction

For the pipeline transportation of waxy crude oil, pour point depressants (PPDs) have been developed and used to improve its flowability at low temperature. As supercritical CO2 (scCO2) flooding becomes a common technique to improve oilfield recovery, how the sensitivity of PPD changes due to the degassed crude oil treated by CO2 should be studied. In this work, the effect of scCO2 extraction on the performance of EVA in improving the flowability of Changqing degassed crude oil is investigated by means of a self-developed scCO2 treating equipment, SARA/HTGC analysis, SEM analysis, pour point test, rheological measurement, asphaltene precipitation test, particle size analysis, DSC test, and microscopic observation. The results show that without EVA addition, scCO2 extraction aggravates the flowability of the crude oil at low temperature. The scCO2 extraction extracts light components from asphaltene aggregates causing asphaltenes to precipitate, which inhibits the asphaltenes on playing a role as the natur...