Small-scale fracture-cavity carbonate reservoirs in Tahe Oilfield have great exploration and development potential，but there are few related data and poor research in the early stage. In order to provide a reference for the exploration and development of this type of fracture-cavity carbonate reservoirs，this paper begins with the concept of small-scale fracture-cave and analyzes imaging data and core characteristics. It is considered that small-scale fracture-cavity reservoirs can be divided into three types：fractured type，vuggy type（including small-scale caves）and fractured-vuggy type（including karst channels between caves）. The comprehensive well seismic calibration of two kinds of reflection characteristics of “disorderly weak”and“weak small string beads”is conducted，and it is considered that although the single well logging interpretation mainly focuses on a single small-scale fracture-cave，there are a large number of small-scale fracture-caves，forming a group of interconnected small-scale fracture-caves，and the overall scale is large. Based on the fracture-cavity system characteristics and genetic evolution process of carbonate reservoirs in Tahe Oilfield，the evolution process of smallscale fracture-caves is divided into topographic infancy，adolescence，maturity and topographic old age. Among them，the fractures and the vugs associated with fractures are mainly formed in the topographic infancy stage. The karst channels and small-scale caves are mainly formed in the adolescence and maturity aged. The small-scale residual caves of cave collapses of various scales and residual karst channels between caves are mainly formed in the topographic old age.