In recent years, Sinopec Shanghai Offshore Oil & Gas Company has continuously carried out exploration and development practices in the Xihu Sag of East China Sea Shelf Basin. In the face of high geological uncertainties caused by sparse wells and limited data offshore and engineering difficulties brought by constrained platform space and limited coverage, along with the significant challenges of high investment and high risk in offshore oil and gas development and exceptionally complex reservoir types in the Xihu Sag, multiple engineering technologies tailored to the characteristics of offshore development have been innovatively developed. The development technology for offshore low-permeability tight gas reservoirs has preliminarily achieved balanced production in strongly heterogeneous, low-permeability tight gas reservoirs. The integrated “rolling evaluation and development” technology for offshore scattered reserves has enabled the effective utilization and cost-effective development of scattered reserves in the East China Sea. The integrated and efficient “rolling evaluation and adjustment” technology for mature areas fully considers the three objectives of rolling exploration, evaluation, and adjustment, and achieves a comprehensive and multidimensional deployment, with implementation results far exceeding expectations. The full-lifecycle enhanced oil recovery technology for offshore water-bearing gas reservoirs effectively controls the water invasion rates in edge-bottom water gas reservoirs, and significantly extends the production lifespan of gas wells. The promotion and application of these technologies enables increased oil and gas reserves, production, and efficient development in the Xihu Sag of East China Sea Shelf Basin, providing a reference for the efficient development of offshore oil and gas fields both in China and abroad. For the efficient development of low-permeability tight reservoirs in the East China Sea, effective utilization of marginal and scattered reserves, and enhanced oil recovery in conventional edge-bottom water gas reservoirs, there are still challenges in theoretical innovation and technological breakthroughs. It is urgent to tackle key technical challenges such as efficient development technologies for low-permeability tight gas reservoirs, engineering technologies for long-distance reserve development around platforms, residual gas characterization in water-bearing gas reservoirs, and integrated utilization of multiple resources in the Xihu Sag, with the aim of continuously promoting the efficient and high-quality development of oil and gas resources in the Xihu Sag of East China Sea.