Research progress of resin and asphaltene’s effect on gelling properties of waxy crude oil

Abstract

The three-dimensional network structure, which is formed by the precipitated wax crystals, is generally considered as the direct cause for gelling of waxy crude oil. Through interaction with wax molecules, the two polar components, namely the resin and asphaltene,participate in the wax crystallization and subsequently alter the wax precipitation properties. This makes it rather complicated to explore the gelling behavior of crude oil. The micro-dynamic behaviors among resin, asphaltene and wax molecules have a direct bearing on the morphology of mesoscopic wax crystals, and then play a decisive role in the macro-rheological property of waxy crude oil multiphase system. Macroscopically, the effect of resin and asphaltene on the rheology of waxy crude oil and its characterization methods were summarized based on the rheological experiments. Mesoscopically, microscopic experiments and molecular simulation were adopted to analyze the effect of resin and asphaltene on the morphology and particle size of wax crystal, as well as the synergistic mechanism among resin, asphaltene and wax crystals. Microscopically, the molecular coalescence and interphase interaction were introduced through the molecular dynamics simulation. Meanwhile, the effect of resin and asphaltene molecules on the gelling properties of waxy crude oil was discussed. Additionally, prospect was made to the application of molecular dynamics simulation in the field of waxy crude oil gelling, which is expected to lay a theoretical foundation for the development of waxy oil pipeline transportation technology and provide reference to the research, development and application of pour point depressant.

Keywords

• waxy crude oil
• resin and asphaltene
• gelling
• multi-scale
• molecular dynamics