Abstract: By taking three mature oil and gas production bases of the Dongpu mature area, the Puguang Gas Field with high sulfur content, and the Inner Mongolia exploration area as the research objects, a series of engineering technologies developed in recent years was systematically summarized, including quality and efficiency improvement of complex fault-block reservoirs, stable production in the middle and late stages of ultra-deep gas fields with high sulfur content, and reserve and production enhancement for oil reservoirs with complex geology and surface conditions in Inner Mongolia. This aims to address the technical challenges including the degradation of backup oil and gas resources and the increasing complexity of downhole operating conditions in the Zhongyuan Oilfield, so as to support the sustained stable and increased production of the oilfield. In the Dongpu mature area, the integrated application of technologies such as refined description of remaining oil, sidetracking of mature wells, differentiated fracturing and enhanced oil recovery (EOR) led to a continuous increase in crude oil production for five consecutive years and a steady decline in the break-even point. The Puguang Gas Field with high sulfur content achieved stable and high production for 16 consecutive years by making breakthroughs in technologies including refined reservoir characterization, targeted potential tapping adjustment, sulfur deposition control and wet gas pressurization, etc. By making breakthroughs in technologies for complex reservoir evaluation and production commissioning, heavy oil and CO₂ composite cold recovery, and low-cost surface processes, the Inner Mongolia exploration area achieved an annual production increase of 70%. Practice demonstrated that targeted engineering technology innovation was the key to supporting stable and increased production in mature oil and gas areas. It was recommended that in the future, efforts should be made to continuously improve the three engineering technology systems, including lean development of complex fault blocks in Dongpu, upgrading the safe and efficient full-industry-chain development of gas fields with high sulfur content, and making breakthroughs in the economic development of low-abundance oil and gas reservoirs in Inner Mongolia. Finally, engineering technical support could be provided for the economic development of the similar oil and gas reservoirs in China.