More than 80% of crude produced in China are those crudes with poor flowability, either waxy crudes with high pour points or viscous heavy crudes. How to transport these crudes safely and with less energy consumption has been a topic for research and development to the petroleum pipeline industry in China, and significant technology development has been made in the past over 40 years, typically the pour-point depressant (PPD) technology for waxy crudes. Flow characteristics of these two kinds of crude and the mechanism for their poor flowability are briefly introduced. The up-to-date research and application of technologies for pour point depression and drag reduction in crude pipelining are summarized, including the PPD technology for waxy crudes, and the dilution pipelining, the oil-in-water emulsion technology and the core annular flow technology for heavy crudes. Development tendency for these technologies is discussed. Suggestions are made to further studies. It is expected that the PPD technology will continue to be a dominant technology for pipelining waxy crudes safely and with less energy-consumption.

Presently in China, studies on the PPD technology should be focused on the highly-waxy Daqing crude oil, which accounts for about one third of total crude oil production in China. For heavy crude oil pipelining, it is believed that the oil-in-water emulsion technology will find more application, and exploitation of offshore heavy crude oil fields in the Bohai Sea of China urgently requires that study on this technology be aimed at pipelines concurrently transporting heavy crude oil and produced water. Further updating of existing technologies and emerging of new technologies call for enhanced basic research, innovative ideas and approaches, and multi-disciplinary studies.