Study on Post-Fracturing Inter-Well Interference in Deep Shale Gas

Field practices have demonstrated that inter-well interference can lead to increased annular pressure in adjacent wells, increasing the risk of casing deformation and ultimately affecting production. Inter-well interference has become a "bottleneck" issue limiting the development of shale gas, necessitating urgent research on its mechanisms. Taking the L well area in the southern region of Sichuan Basin as the research object, this article establishes a numerical simulation model for the fracturing and exploitation of deep shale gas horizontal wells. The study analyzed the mechanisms and influencing factors of inter-well interference during the post-fracturing exploitation process. Key findings include that The higher conductivity of the hydraulic fractures, the larger fracturing scale, and the smaller well spacing, the more likely it is for inter-well interference phenomena to occur. It was also found that when there is no interference from natural fracture zone, batch exploitation can lead to more pronounced inter-well interference phenomena. Natural fracture zones between wells enhance this interference, but their impact is reduced during batch exploitation due to pressure recovery in the first exploited well. The study also highlights that the flow conductivity of natural fractures significantly affects inter-well interference during batch exploitation. Overall, this research provides insights into optimizing shale gas exploitation strategies in complex geological environments. 1 INTRODUCTION The Sichuan Basin boasts the largest shale gas resources in China, with its annual shale gas production exceeding 90% of the country's total output. It is the main battleground of shale gas development in China. Based on extensive theoretical research and field practice, the multi-cluster fracturing process of shale gas horizontal wells has made a technical breakthrough. At present, the number of wells with interference between wells accounts for 50% in W area, which directly affects the production of old and new wells with interference (Guo et al., 2022). A large number of field practices show that inter-well interference will lead to the increase of annulus pressure in adjacent wells, increase the risk of casing variation, and eventually affect production. Interference between wells has become a "stuck neck" problem restricting shale gas development, and an effective method to evaluate interference is urgently needed.