Viscoelastic performance evaluation of petrol oil and different macromolecule materials

This study involved conducting an experimental investigation into the flow properties of different petrol oil–macromolecule material emulsions with regard to their viscous and elastic behaviors to assess the performance of the two most used polymers, Alcoflood and Xanthan, in the enhanced oil recovery (EOR) stage. Rheostress RS100, equipped with a cone-plate device, was employed to conduct these experiments and analyze the results. Moreover, the study involved comparing the emulsion flow in the presence of Alcoflood and Xanthan in terms of complex, storage, and loss moduli (G*, G`, and G``, respectively). Thirty-two different experimental samples of oil–Alcoflood and oil–Xanthan emulsions were prepared to cover a wide range of polymer (0–104 ppm) and petrol oil concentrations (0 –75 % by volume). A detailed examination of the viscoelastic profiles of the petrol oil macromolecule emulsions was performed over a wide frequency range from 0.1 to 10 s-1. All viscoelastic tests for both types of emulsions were conducted under a stress effect of 1 Pa to ensure that these tests were performed within the linear viscoelastic range. For a lower polymer concentration of 500 ppm, both AF1235 and Sigma oil emulsions exhibited linear viscous profiles with virtually identical G* of 50.8 Pa at a frequency of 1 s-1. However, when the polymer concentration was increased to 5000 ppm, all emulsions demonstrated viscoelastic profiles, with Sigma emulsions substantially surpassing the corresponding AF1235 blends. In the case of a 25 % oil–5000 ppm polymer mixture, the Sigma emulsion shows a G* of 827.9 Pa, whereas the AF1235 blend displays a G* of 371.9 Pa at 1 s-1. All tested emulsions of both polymers exhibit a higher elastic behavior than their corresponding viscous profile. The elastic response of the Sigma emulsions is much higher than that of the AF1235 blends. Both the elastic and viscous behaviors increase gradually with the addition of petrol oil. The current study recommends the use of xanthan gum for EOR under high shear conditions owing to its superior resistance compared to that of the Alcoflood polymer. However, the Alcoflood polymer has revealed better results in terms of sweep and oil extraction.