The pipeline serves as a vital link connecting the upstream and downstream segments of the oil and gas industry chain, playing a crucial role in modern energy systems and comprehensive transportation systems. Amidst the deepening institutional reforms within the oil and gas sector and the strategic goal of "carbon peak and carbon neutrality", oil and gas pipelines are evolving towards large scales, networking and diversification, which brings both new opportunities and challenges to the operation management of extensive and intricate pipeline networks. Leveraging insights from the current development status of China's oil and gas pipeline networks, this paper analyzed the trends and difficulties in the research of oil and gas pipeline network operation across four pivotal domains: system analysis, simulation and optimization, operation monitoring, and new pipeline transportation. Relevant research included reliability and resilience evaluation technology for pipeline network system, operation simulation and transportation optimization technology for pipeline networks, pipeline body monitoring and repair technology, as well as pipeline transportation technology for hydrogen, methanol, liquid ammonia, and LNG. In light of the new era of "one network nationwide" and the emerging trend of "multi-energy complementarity", forward-looking technological research directions have been proposed, such as digital twin, intelligent scheduling and control, intelligent early warning, and multi-network integration, aiming to drive the safe, efficient, and green development transformation of China's oil and gas pipeline networks. Finally, this paper put forward the prospect: at this stage, it is necessary to capitalize on China's energy and resource endowments, accelerate the adaptation to the operation mode of pipeline networks amidst the new landscape, and play the role of oil and gas pipeline networks as an energy artery in the new stage of "one network nationwide". In the future, it is necessary to progressively advance the flexible transportation capabilities of pipeline networks across multiple media, and tap the development potential of oil and gas pipeline networks within comprehensive transportation systems and integrated energy systems.