## 1 Introduction  
The decline in conventional oil and gas exploitation has led to increased attention toward unconventional oil and gas reservoirs [1, 2, 3, 4]. Tight sandstone reservoirs, such as those within the Chang 7 member of the Upper Triassic Yanchang Formation in the Ordos Basin, China, are distinguished by extensive fracture development [5, 6, 7, 8]. These fractures notably influence the \"sweet spots\" within the reservoir. Although fractures may not significantly increase the reservoir space in low-permeability sandstones, they substantially affect the connectivity of the reservoir [9]. The presence of natural fractures is crucial for guiding subsequent hydraulic and artificial fracturing processes, making the study of fractures in tight sandstone highly valuable [2, 10, 11].  
Although previous studies have thoroughly analyzed the structural and sedimentary aspects of the Yanchang Formation [7, 8, 12], research on fractures within the Chang 7 member remains inadequately systematic and in-depth. Several issues persist, including the reliance on single-scale data for fracture characterization, which has led to a limited understanding of fracture development. Earlier research on fractures in the tight sandstone of the seventh member of the Yanchang Formation was based on core descriptions or thin sections [6; 13; 14]. The scale used for describing and characterizing fractures in tight sandstone has been overly narrow, resulting in an unclear understanding of fracture development characteristics across various scales. Furthermore, a single logging curve demonstrates limited effectiveness in fracture identification, which can introduce uncertainty when employing conventional logging methods [15; 16; 17]. Although imaging logging offers relatively accurate fracture identification, it is costly and impractical to apply to every well [18]. Accurate identification of fractures through conventional logging curves is an urgent issue that must be resolved in tight sandstone reservoirs. Additionally, earlier studies have only provided qualitative analyses of the primary controlling factors affecting fracture development in tight sandstone, with quantitative factors remaining unclear. These limitations impede a comprehensive understanding of fracture distribution and development.  
Given the current situation, the primary issue with characterizing fractures in tight sandstone is the overly narrow scale of analysis. Moreover, the high cost of imaging logging, though accurate, limits its application across all wells, contributing to gaps in understanding fracture characteristics on a broader scale [19]. Additionally, while various factors influence fracture development in tight sandstone, research into the primary controlling factors has been limited, further complicating efforts to enhance resource extraction [18; 20]. To address these issues, it is essential to identify and characterize fractures across multiple scales and quantitatively determine the primary controlling factors of fracture development [21]. Our study aims to integrate imaging logging data from selected areas with conventional logging, allowing for the delineation of fracture development segments within the study area. This study offers a more comprehensive characterization of fractures in the tight sandstone of the Chang 7 member, providing a clearer understanding of their development. Additionally, we will investigate the primary controlling factors of fracture development in tight sandstone reservoirs.  
This study is of high importance, as it seeks to fill the existing knowledge gaps in fracture characterization within the Yanchang Formation's tight sandstone reservoirs [5; 6]. By integrating multi-scale data, this research will provide a more accurate and systematic understanding of fracture development and controlling factors. Such insights will contribute to the optimization of hydraulic fracturing techniques, enhancing the effective development of tight oil resources [22; 23].