This paper is the result of oil and gas exploration engineering.

Objective With the rapid expansion of shale gas production in China, deep shale gas reservoirs at burial depths of 3500–4500 m have become critical targets for exploration. However, complex geological conditions and stress disturbances from fracture systems significantly hinder development.

Methods This study focuses on the Wufeng−Longmaxi Formation in the North Luzhou district of the southern Sichuan Basin. By analyzing the spatial distribution of fractures and conducting single−well geostress evaluations, the characteristics of stress disturbance caused by fractures were clarified. A comprehensive table and distribution map of stress disturbance elements were created.

Results (1) Fractures in the study area exhibit diverse types and phases, with a tectonic style dominated by "syncline, slope, and anticline slope." The fracture combinations primarily follow a pattern of "syncline, superposition, and anticline backslope". (2) The regional geostress state is complex, with average stress values of S_H(112.7 MPa) >S_v(106.6 MPa) >S_h(98.8 MPa). Fractured zones exhibit stress values 5−35 MPa lower than non−fractured zones. The maximum horizontal stress orientation ranges from 75° to 120°, showing significant variability across wells. (3) Fractures influence stress distribution, with stress disturbance increasing alongside fracture levels. The disturbance range of Class II fractures spans 1.43−1.85 km. NEE—EW fractures exhibit the largest disturbance ranges 0.94−1.85 km.

Conclusions A fracture disturbance distribution map was developed for the North Luzhou district, dividing the area into fracture and non−fracture zones to enable hierarchical evaluation of development units. Optimized layouts for horizontal well sections in fractured and non−fractured zones were proposed, offering guidance for future production.