<p>Natural gas hydrate (NGH) is a promising energy resource, but its exploitation often induces reservoir instability due to sediment weakening and subsidence from hydrate dissociation. Conventional reinforcement approaches either compromise reservoir permeability or pose environmental concerns, highlighting the need for safer and more sustainable solutions. Microbially induced carbonate precipitation (MICP) offers a bio-mediated solution by injecting bacterial suspensions and cementation solutions into sediments, where carbonate minerals precipitate to bind soil particles. This process strengthens the reservoir while preserving pore connectivity and permeability. The effectiveness of MICP depends strongly on treatment strategies and operating conditions. This study investigates the effects of MICP reinforcement strategies on gas hydrate reservoirs, with emphasis on bacterial transport, CaCO₃ precipitation, hydraulic evolution, and production response under different bacterial activities, injection flow rates, and reinforcement stages. Results show that the extent and uniformity of CaCO₃ precipitation exhibited strong spatial heterogeneity controlled mainly by injection flow rate and bacterial activity. Although MICP reduced near-well permeability, the resulting cumulative gas production loss remained below 7%, indicating that localized permeability impairment does not directly lead to a proportional long-term production loss. Low rates or high activity significantly enhance the reservoir stiffness and reduce the maximum subsidence by up to 33% by forming a concentrated near-well reinforcement zone. A clear trade-off was observed among subsidence control, permeability preservation, and reinforcement extent, with optimal performance achieved with reinforcement during the mid-to-late production stage, a medium-to-high injection rate, and low bacterial activity.</p>