[Objective] The fault-fracture reservoir in the southern Ordos Basin have large reserves, high oil abundance, and good development prospects. However, their internal structures are complex and varied, and the existing research results cannot support a detailed description of fault-fracture reservoirs. [Methods] In order to clarify the internal structural characteristics of the fault zones and construct a fine fault zone development model, this paper uses unmanned aerial vehicle oblique photography technology to conduct high-precision sampling and modeling of various typical fault-fracture reservoir outcrops in Xunyi area. We use self-developed software to collect and analyze three-dimensional data of the fault-fracture reservoir, and further study its internal structural characteristics and fracture development patterns. [Results]The results indicate that: (1) There are three types of fracture bodies developed in the Xunyi area: transtensional segment (half-negative flower pattern, graben pattern), pure strike-slip segment (closed translational pattern), and compression twisting (horst pattern); (2) Based on the comprehensive parameters such as the development of faults, rock morphology, and fracture development characteristics in the field outcrop, fault-fracture reservoir are divided into sliding breaking zones, induced fracture zones, and substrate zones. The structural patterns and quantitative rules of different types of fault-fracture reservoirs vary greatly, with only half-negative flower pattern and graben pattern fault-fracture reservoirs developing wide sliding breaking zones; (3) The fracture density is affected by the fault-fracture reservoir types，separation，fault spacing，block position，and sand layer thickness. Overall, the highest density is found in the graben type fault-fracture reservoir, followed by the half-negative flower patterned fault-fracture reservoir, and the lowest is found in the closed translational and horst type fault-fracture reservoirs; The larger the fault distance, the smaller the fault spacing, and the lower the rock thickness, the more developed the fracture; In the same fault-fracture reservoir, the density of fracture in different blocks shows different trends of variation. [Conclusion] This study identified four patterns and quantitative rules of fault-fracture reservoirs, summarized the influence of different factors on fracture density, and provided more accurate quantitative structural characteristics of fault-fracture reservoirs for underground reservoir characterization.
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