Abstract: Small and middle sized karst fractures and vugs in the Lower-Middle Ordovician epikarst zone in the main area of Tahe oilfield are important succeeded fields for oil-gas exploitation. It is vital to intelligently identify epikarst zones and determine the development laws of fractures and vugs. Through the integrated utilization of three-dimensional seismic data, imaging logging, conventional logging, core and thin section data, the artificial intelligence identification method for bottom interface of epikarst zone was established to describe the structural characteristics and patterns of epikarst fractures and vugs at different scales, the main controlling factors for the development of epikarst zones were explored, the geological model of epikarst fracture-vug development was summarized, and the favorable development sites for such reservoirs were pointed out. The results show as follows. (1)The self-similarity coefficient method and dynamic time sequence matching method can realize the intelligent identification of bottom interface in epikarst zone and overcome interference of subjective factors. (2)The epikarst zone in the main area of Tahe oilfield is 4.5 m to 62.5 m in thickness, with an average of 24.0 m. The epikarst zones of the main area demonstrate 5 different structural styles of karst fractures and vugs, dominated by high-angle solution expansion cracks, and caves and dissolution pores can be observed in partial areas. (3)Multi-attribute combination based on "Thin Likelihood attribute analysis+50 Hz frequency division+diffraction wave separation imaging" can effectively predict small and medium-sized fractures and vugs. (4)Different levels of karst paleogeomorphology, karst drainage system as well as faults and fractures jointly controlled the development of fractures and vugs in epikarst zone. The development models of epikarst fractures and vugs controlled by third-level karst landform and coupling gullies with faults and fractures were established separately. (5)The gentle slope and the core of karst residual hills in the karst plateau area are the most favorable for the development of epikarst fractures and vugs, followed by the gullies with developed faults and fractures in some areas. These zones have good development potential.