Influences of depressurization rate on natural gas hydrate production characteristics in stepwise depressurization: Two-dimensional experimental study.

This article focuses on the effects of different stepwise depressurization rates on natural gas hydrate (NGH) production characteristics using a self-developed two-dimensional simulation system with a single horizontal well. The study finds that a medium depressurization rate significantly increases late-stage gas production—up to 59% of total production—but also poses substantial risks to reservoir stability and well control safety due to a high peak gas production rate. Temperature–pressure responses during depressurization reveal complex hydrate decomposition behaviors influenced by depressurization rates, with a weak linear relationship observed between normalized average gas production rate and depressurization rate in the later production stage. The research suggests that mixed depressurization strategies, adjusting rates across production stages, may optimize gas yield while enhancing safety and environmental sustainability, though further testing with multi-branched wells is recommended for broader application.