In response to the poor physical properties, strong heterogeneity, high injection production ratio, and low formation pressure of ultra-low permeability reservoirs in the Ordos Basin, as well as the contradiction between the difficulty of establishing displacement in some reservoirs, the presence of injected water flowing along fractures, the small volume of water flooding and low recovery rate, the logging identification marks, stacking style, lateral contact mode, and water breakthrough characteristics of single sand bodies are first finely characterized. Secondly, a microscopic visualization simulation model was used to study the remaining oil occurrence patterns under different pore structures. Finally, the development of fractures and high permeability zones in the study area, as well as their water drive patterns, were summarized. The research results are ultimately applied to geological modeling to guide the fine injection and production adjustment of small reservoirs, determine the cyclic injection system and cycle, and construct a full life cycle fine injection and production technology for ultra-low permeability reservoirs. Guiding the injection and production adjustments of ultra-low permeability reservoirs in Huaqing and Huanjiang oilfields for about 15 000 times, with an average increase in oil recovery rate of 0. 2% , alleviating reservoir decline by 1. 2% , and an annual cumulative increase of over 50 000 tons of oil.