The scale and complexity of world crude oil flows are increasing. From the perspective of complex network analysis, we examine the relative status and their changes of the major trading countries and their corresponding geopolitical regions, and analyze the competition and cooperation between China and these geopolitical regions, which are conducive to a comprehensive review of the overall pattern, key cooperation countries, and possible model innovation of China's oil cooperation in terms of cooperation with exporting and importing geopolitical regions. The results show that: (1) World crude oil flows are still dominated by the main export geopolitical regions, and gradually evolved into the three dimensional competition patterns of Russia - Central Asia, the United States - Canada and the Middle East. However, the diversification and relative status changes of the exporting geopolitical regions also provide opportunities for the importing countries to adjust their cooperative relations. (2) The Asia-Pacific region has gradually become the focus of the competition and cooperation in the world crude oil flows. However, due to the lack of mutual exchange among the major importing countries in the Asia-Pacific region, the overall status of the region and its control over the world crude oil flows have been lowered. Correspondingly, China is deeply trapped in the three major dilemmas of import decentralization, the game of major exporting countries and the check and balance of major importing countries. (3) In terms of cooperation with exporting geopolitical regions, China should focus on strengthening multilateral cooperation with Russia - Central Asia geopolitical region, appropriately strengthen bilateral cooperation with United States - Canada geopolitical region, and consolidate and balance diversified cooperation with the Middle East geopolitical region; as for Africa and Latin America, China should stabilize the existing cooperation and innovate the cooperation mode, such as bringing the output of China's oil investment in Africa to the international market, and encouraging China Petroleum Purchase Federation of Independent Refinery to cooperate with large oil trading companies to enter the Latin American oil market. In terms of cooperation with importing geopolitical regions, China should conduct internal mutual exchanges with importing countries in the Asia-Pacific region based on the import share coordination mechanism, diverse-source competition mechanism and the division and cooperation mechanism of the international trade center. The above oil cooperation is conducive to improving China's competition and cooperation environment in the world crude oil flows, ensuring the balance of oil supply and demand, and reducing supply risks.

Along with the proposal of "the Belt and Road" Initiative, energy connectivity has become an essential component of China's overseas cooperation. In "the Belt and Road" energy cooperation, it is of great significance to depict and compare the cross-border relations from the dual perspectives of direct energy trade and embodied energy transfers. The main conclusions include: (1) From the direct perspective, countries such as Saudi Arabia and Russia are essential energy importers of China; (2) From the embodied perspective, China provides a large amount of energy-intensive products to countries such as India, Singapore and Thailand within "the Belt and Road" region; (3) China's direct energy trade with "the Belt and Road" region is in deficit, while the embodied energy transfer is in surplus; (4) Through synthetic consideration of direct energy trade and embodied energy transfers, China can further extend the radiating effects of different energy relations, and provide a solid foundation for energy connectivity and cooperation partnership between China and "the Belt and Road" countries.

Liquefied petroleum gas (LPG) plays a very important role in the global clean energy consumption market. It is transported by vessel between ports, and the ports have formed a series of extremely close-knit trading communities through local dense trade relations. In this study, we build transportation networks based on the global LPG vessel trajectories data from 2013 to 2017, and adopt a community detection method to analyze the characteristics of this type of trading community and evolution trend. The results show that: (1) The ports in the LPG trading community are more closely connected, and the hub ports in different communities are becoming closer over time. (2) The number of ports in each trading community shows an increasing trend, and the ports in the same community are becoming more geographically agglomerated. (3) Communities formed in the Asia-Pacific region, the Middle East, North and West Europe and the Mediterranean region have maintained an important position in the global LPG trade, while those in the Americas have gradually evolved from a relatively isolated community to one that has close ties with other communities over time.