Mechanisms of seepage damage evolution in gas storage under the coupling effects of drilling–completion–injection/production full cycle

To address the lack of evaluation methods for the impact of reservoir damage on seepage capacity in gas storage reservoirs, this study investigates the dynamic evolution of seepage damage throughout the “drilling–completion–injection and production” cycle in deep gas storage reservoirs. Using full-process simulations and multi-scale characterization, the seepage attenuation mechanism was analyzed. Taking the Wenba gas storage sandstone core (Tuha Oilfield, China) as the object, dynamic contamination evaluation, fluorescence tracer invasion depth observation, and multi-cycle injection–production experiments quantified seepage damage. Results show that polyamine drilling fluid microparticles (<10 μm) block pore throats, reducing high-permeability core seepage (12.47 mD) by 35%. Perforation completion increases near-well resistance by 40%, while open-hole screen pipe completion restores seepage to 82.5%. Multi-cycle injection–production recovers deep seepage to 78%, while acid treatment (12% HCl) improves efficiency by only 5.3%. The study reveals the synergy of drilling fluid particle matching, completion methods, and injection–production cycles on seepage and proposes a permeability recovery-based reservoir adaptability optimization, supporting efficient seepage channel construction in deep reservoirs.