One of the current trends in oil industry is to extract oils in subsea conditions in harsher conditions such as very cold environments. This brings extra challenges for the transportation and processing of oil since waxes can crystallize and deposit at low temperatures leading to decreased productivity. The consequences of wax crystallization can be mitigated by the addition of pour point depressants (PPDs), which lower the temperature at which the waxy oil loses its ability to flow freely. However, there are still high uncertainties regarding their exact behavior and inhibitors must be tailored on a case-to-case basis. This project, which started in autumn 2020, is the continuation of the activities performed in the project “2.2 Modelling of wax crystallization and deposition” (Jost Ruwoldt). We are currently developing and implementing new techniques and procedures to characterize and quantify the interactions between waxes, crude oil components (asphaltenes), and wax inhibitors to understand the complex interactions in waxy crude oils and how PPDs work.

EXPERIMENTAL APPROACH

The activities are divided in 2 parts:
•    The first part focuses on research using nuclear magnetic resonance (NMR) to study the effect of asphaltenes and PPDs on the interactions between the crystal network and the dissolved species, alongside with the wax precipitation evolution with temperature. The study starts from the analysis of model systems and gradually progresses towards real systems. 
•    The second part involves atomic force microscopy (AFM) investigations of the interactions between wax crystals and inhibitors in solvent or crude oil environment at nanoscale level.  

Equinor is collaborating with the project by providing selected samples for the PhD project.