Abstract: To address the drawbacks of conventional acidizing fluids, including fast acid-rock reaction rates, limited effective stimulation radius, insufficient reservoir modification in far-well zones, excessive acid waste, as well as poor high-temperature retarding performance and environmental hazards of existing solid acids, solid acid particles were synthesized using carbamide and oleum as raw materials, and a slow-release solid acidifier ZY-Y was fabricated via spray coating with degradable materials. Laboratory performance tests reveal that at 90 ℃, the continuous acid-rock reaction duration of ZY-Y reaches 350 minutes, 7.1 times that of gelled acid, with a rock dissolution rate exceeding 93%. It boasts excellent resistance to formation water dilution, enabling effective stimulation of far-well reservoirs. Moreover, it creates prominent uneven etching, which helps enhance fracture conductivity. Field applications in 8 deep wells over 6,500 meters deep in western oilfields demonstrate an average oil production increment rate of 51.6%, and a typical well achieved a cumulative oil increment of more than 12,000 tons, with the overall acidizing stimulation cost reduced by 21.9%. Laboratory research and field practices verify that the slow-release solid acidifier ZY-Y delivers outstanding retarding capacity, high dissolution efficiency, environmental friendliness and economic benefits. It can realize deep acidizing modification of carbonate reservoirs, is suitable for plug removal and production enhancement in intermediate and far zones of mature wells, and possesses great value for large-scale popularization.