Objective This study aims to clarify the fracture development pattern and differential productivity−controlling mechanisms of the fractures in Xujiahe Formation tight sandstone under the complex structural background in the northeastern Sichuan Basin. The goal is to enhance the efficiency of natural gas exploration and development and improve single−well productivity in the region.

Methods Based on detailed interpretation of 2D seismic and 3D seismic data of Sinopec Exploration areas, the structural characteristics and evolution of the Xujiahe Formation was investigated. The characteristics and spatial variation of fractures are identified through field outcrop observations, core description, borehole imaging interpretation, and production analysis. And the main controlling factors of fracture development and their impact on reservoir productivity are further analyzed.

Results The findings indicate that: ① The Xujiahe Formation in the northeastern Sichuan Basin experienced three stages of tectonic deformation during the early−middle Yanshanian, late Yanshanian, and Himalayan period. Based on deformation styles, the study area is divided into five tectonic zones. ② NE−trending Weak Deformation Zone and Steep Structural Zone are dominated by low−angle and bedding−parallel fractures with small apertures, whereas high− and medium−angle fractures with wider apertures are more developed in other zones. Tensile fractures are well developed in Tongnanba Anticline and NE−trending Weak Deformation Zone, although many are significantly filled. Shear fractures dominate in other zones, and most are unfilled or only partially filled. ③ Fracture development is jointly controlled by three−stage tectonic superposition, structural styles, and lithological assemblages. From west to east, fractures increase progressively. NW−trending fault−related fractures have a significant positive impact on well productivity, and fracture development shows a positive correlation with production.

Conclusions Late−stage NW−trending faults and their associated fractures play a key role in controlling productivity of tight sandstone gas reservoirs and should be considered favorable targets for future exploration and development.