Abstract：At present, there is no systematic and perfect method for the characterization of granite fractured reservoirs. Influenced by weathering, lithology, structure, and other factors, the development of pores, fractures, and caves in the reservoirs is highly heterogeneous, which increases the difficulty of their characterization. Therefore, taking the granite buried-hill B oilfield in Chad as an example, this paper proposes a multi-scale fracture modeling method. The method combines the deterministic modeling method with the stochastic modeling method and uses the results of fracture prediction based on pre-stack omnidirectional AVAZ (amplitude variations with azimuths) inversion and those based on post-stack ant tracking to establish a small-scale fracture and a large-scale fracture model respectively under the control of the fracture seismic facies. The former can provide anisotropy parameters, fracture density, direction, and other parameters, with which fractured reservoirs can be identified and evaluated. The latter can identify and track fractures on the seismic data, and each identified fracture has measurable length and direction. Furthermore, the equivalent fracture model is used to realize the quantitative characterization of fracture permeability. The results of comprehensive fracture prediction with post-stack and pre-stack seismic data are closely combined with the development geology, and well logging, geological, drilling, and production data are fully integrated to form a systematic fracture model that can comprehensively reflect the fracture information on different scales in various data. The fracture model provides a technical basis for the optimization of development well deployment, and the equivalent permeability calculation results of the multi-scale fracture model are more consistent with the characteristics of fluid flow, which lays a foundation for the numerical simulation of reservoirs.
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