Identification and characterization of fracture-connecting components in carbonate fractured-vuggy reservoirs

The spatial structure of fractures in the carbonate fractured-vuggy reservoirs in the Tahe Oilfield was very complicated; hence the identification and characterization of fracture-connecting components were difficult. Based on modern karst mode, we selected isolated caves, karst rivers and micro-fractures to identify seismic properties. Seismic facies analysis was used to study caves and fractures. 3D geologic network was applied to establish a geometric geologic model quantitatively, which could describe the fracture-connecting components. Amplitude gradient properties could effectively determine the boundaries between "beaded" strong reflectance and formation reflectance, which could detect and image the spatial distribution of caves with beaded reflectance. Maximum curvature attributes could effectively describe the plane linear features and geometric boundary characteristics of faults and fractures, which showed the distribution of fractures. The fracture-connecting components described by karst seismic facies described the geometric states and spatial extensions of fractured-vuggy reservoirs; hence realized the precise description of internal structure and communicating channel, and provided important technical supports or the development of fractured reservoirs.