Numerical Simulation of Inter-Well Synergistic Effects during Multi-Well Depressurization Production of Natural Gas Hydrates

Abstract Well layout configuration is critical for gas hydrate production as it dictates pressure spreads and dissociation front propagation. This study conducted numerical simulations for single-well, two-well, and several multi-well layouts. Gas production rate, water production rate, and volume ratio of gas to water were calculated to describe production behavior based on the geological conditions of the SH7 site in the Shenhu Area, northern South China Sea, to investigate multi-well development dynamics. A synergistic effect coefficient (Sec) was introduced to quantify the production enhancement per well in multi-well systems. Results demonstrate that while increasing well count enhances total recovery, the gains are inherently nonproportional, revealing a distinct synergistic effect limitation. Well layout and spacing significantly control performance; specifically, the ring layout and larger well spacing outperforms others by establishing a more homogenized pressure distribution. Mechanistic analysis reveals that while inter-well pressure superposition expands the effective dissociation region, the increasing competition among flow pathways and phase redistribution progressively constrain further enhancement. These coupled processes govern the nonproportional evolution of synergistic effects. These findings provide a mechanistic basis for optimizing well spacing and architecture in large-scale hydrate commercialization.