This study addresses the challenges in understanding production patterns during well shut-in and reopening in tight sandstone gas reservoirs caused by complex pore structures and high water saturation, aiming to elucidate seepage mechanisms during well operations, identify key influencing factors, and establish theoretical guidance for field well selection and intervention timing during production adjustment. By analyzing field data quantifying gas and water production variations before and after shut-in periods unaffected by external interventions, we identified two critical parameters—shut-in duration and water production levels—and classified four distinct shut-in types. Integrated core experimental data revealed the influence mechanisms of afterflow effects, imbibition phenomena, and pressure-sensitive effects of relative permeability curves during well operations. A productivity model was developed to qualitatively analyze parameter variations based on flow mechanisms. Research demonstrates that Early-stage gas production variations during reopening reflect the macroscopic manifestation of competing mechanisms: permeability reduction (negative effect) from imbibition in near-wellbore small pore throats versus production enhancement (positive effect) from pressure buildup. Late-phase production changes predominantly manifest macroscopic alterations in gas phase flow capacity caused by pressure-sensitive characteristics of relative permeability curves. Shut-in operations should prioritize low-water production periods regardless of causes, as prolonged shut-ins during high-water production stages significantly impair productivity, while short-term closures exhibit minimal impact. These findings provide critical guidance for optimizing well selection and operational timing during production adjustment, effectively mitigating unnecessary production losses from field operations or output optimization.