Abstract

Mature shale gas areas commonly retain substantial remaining resources after long-term depletion, but their redevelopment potential is governed by pressure redistribution, present-day stress evolution, natural-fracture stability, and target accessibility. Taking the HuangJinBa YS108 shale gas area as an example, this study proposes an integrated redevelopment zoning workflow that couples geological conditions, geomechanical constraints, and fracture-slip risk. Two types of remaining targets are identified: inter-well remaining resources and wellbore-control blind-spot resources. A geological-condition evaluation index (GCEI) is then constructed using remaining gas content, effective reservoir thickness, and remaining pressure. The zoning results are further constrained by the Anderson stress-regime index, horizontal stress difference, maximum horizontal stress orientation, and a Mohr–Coulomb-based natural-fracture-slip-risk index. Results indicate that L113 and L112 are the main depleted layers, whereas L114, L111, and the Wufeng Formation retain further redevelopment potential. Favorable zones are mainly distributed around platforms H24, H1, H3, H23, H13, and eastern H20. Long-term depletion reduces the minimum horizontal stress in densely developed areas and generally improves fracture stability, although local fracture intersections still present elevated slip risk. The final zoning provides a practical basis for redevelopment decision-making: platforms H24, H1, H3, H23, H13, and eastern H20 can be prioritized for near-term screening; inter-well targets should be developed using conservative infill strategies with controlled fracture length; and wellbore-control blind-spot targets can be stimulated more intensively under controllable fracture-slip risk.

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