Effect of dispersed water on the paraffin crystallization and deposition of emulsified waxy crude oil via dissipative particle dynamics

The gelation of emulsions is a notorious problem during the transportation of crude oil. In this study, the impact of dispersed water on the paraffin crystallization behavior in waxy crude oil was investigated using the mesoscopic dissipative particle dynamic method. The results indicated that water cuts affect the nucleation of wax crystals. The homogeneous nucleation of waxy crystals is important in systems when the water cuts are lower than the critical value (47.75 mol% of the studied systems), whereas heterogeneous nucleation becomes dominant when the water cuts are larger than the critical value. In addition, the water accelerates the nucleation and build-up of the crystal structure. Furthermore, the wax appearance temperature of the system experiences a steady increase when the water cut is lower than the critical value. The wax appearance temperature increases abruptly when the water cuts are larger than the critical value. This indicates that the injection of water further deteriorates the low-temperature rheological behavior of the emulsions. The critical water cut also impacts the competitive capture relationship between the water molecules and paraffin molecules.