Design and Field Application of Staged Composite Slugs for Gas Channeling Control in Underground Gas Storage

The engineering problem in producer-side foam treatment is to retain placement access while developing sufficient flow resistance. This study integrates conventional and enhanced foaming fluids, a water spacer, imbibition fluid and light-oil displacement with explicit volume estimates and pressure-responsive injection. The novelty is field-scale process organization rather than new chemical development. Screening at 140 °C and 2.34 × 105 mg/L salinity supported initial concentrations of 1.0 wt% base formulation, 0.2 wt% xanthan gum and 1.5 wt% imbibition formulation. Single-core and parallel-core recovery gains were 13.64 and 21.95 percentage points. In pilot well P1, the three principal injected volumes were 287, 288 and 288.6 m3. Over 212 calendar days, oil production averaged 19.01 t/d and cumulative-production GOR was 1082.87 m3/t, 78.6% below the historical reference. Reference-equivalent incremental oil was 3167.88 t, varying from 2952.14 to 3311.71 t across ±20% baseline-GOR scenarios. The pilot demonstrates implementability; a single well without a matched control or downhole placement monitoring cannot establish comparative superiority or spatial slug boundaries.