Mechanism and Control of Sand Production in Depleted Sandstone Gas Storage Under Cyclic Loading

This study addresses the sand production issues in injection-production wells of depleted sandstone gas storage under cyclic loading, employing multi-scale numerical simulations, laboratory experiments, and engineering optimization to systematically reveal the sanding mechanisms and propose control strategies. A multi-field coupling numerical model incorporating cyclic stress, fluid flow reversal, and gas-water interface fluctuations was developed based on the Mohr-Coulomb elastoplastic model and ALE adaptive meshing. Results indicate that the shear failure zone around the well expands exponentially with cycle count, triggering critical sand production when the equivalent plastic strain in the minimum horizontal stress direction reaches 0.028 (pressure differential: 22.5 MPa). Cyclic pressure core flow experiments demonstrated a nonlinear relationship between cycle count and sand production, with sand volume increasing as a power function (R2 = 0.96) when pressure amplitude exceeds 15 MPa. An orthogonal experimental design identified a composite sand control solution combining wire-wrapped screens and gravel packing, reducing sand production by 78.6%. Sensitivity analysis established optimized operational parameters, including a pressure gradient below 3.5 MPa/m and injection-production rates of 8–12 × 104 m3/d, providing theoretical support for safe gas storage operations. These findings offer innovative solutions for sand control and operational optimization in deep sandstone gas storage.