Research Status and Outlook of Mechanism, Characterization, Performance Evaluation, and Type of Pour Point Depressants in Waxy Crude Oil: A Review

With the depletion of conventional oil resources, waxy crude oil has become a focus of development. Wax deposition is prone to occur in crude oil at low temperatures, and can easily cause pipeline blockage. Hence, preventing wax deposition while ensuring the safety of pipeline transportation and reducing energy consumption has become a popular research topic. Pour point depressants are normally used to solve the wax deposition problem. In this paper, recent research on pour point depressants is reviewed and the mechanism by which pour point depressants inhibit wax deposition is clarified. Commonly used characterization methods and performance evaluations in the research of pour point depressants are summarized. According to the composition of pour point depressants, the chemical structures and effects of polymers, surfactants, green pour point depressants, and nanohybridized pour point depressants are analyzed. Among these four, nanohybridized pour point depressants have better application prospects due to their unique size, excellent heat resistance, stability, and exceptional optical, electrical, and magnetic properties, which can effectively improve the inhibition performance of pure polymers or surfactants. Finally, future challenges in pour point depressants are analyzed.