Targeted Development of Residual Shale Gas Resources in Longmaxi Formation: Practices and Insights from Jianwu Syncline, Changning Block

To address the challenges of accelerated production decline in the middle-late development phase and unclear distribution of residual resources in the Longmaxi Formation shale gas reservoir within the Jianwu Syncline of Changning Block, aiming at targeted development of residual resources and enhanced reserve recovery efficiency, this study focuses on remaining resources assessment and technical strategy research in the block. Through integrated geological modeling and dynamic production data analysis, the reserve recovery characteristics were revealed: The lower gas zones remain underutilized, while the upper gas zones are largely undeveloped. A novel development strategy termed “Infill Development + Three-Dimensional Well Network Synergy” is proposed: For the lower gas zones, horizontal well trajectories should primarily traverse sub-layers ①-③, with a vertical spacing ≥5 m between parent-child wells. The upper gas zones should target sub-layers ④ using a “W-shaped” three-dimensional well pattern. The study concludes that combining infill well patterns with three-dimensional well network collaboration, based on the existing primary well pattern in the Jianwu Syncline of Changning Block, significantly improves reserve recovery efficiency.