This article is the result of shale 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 dorsal slope." The fracture combinations primarily follow a pattern of "syncline, superposition, and dorsal 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.