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Interlayer fracture effects on depressurization-induced hydrate dissociation in reservoirs with underlying free gas.

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Title:	Interlayer fracture effects on depressurization-induced hydrate dissociation in reservoirs with underlying free gas.
Authors:	Gu, Linlin¹ (AUTHOR), Sun, Shicai¹ (AUTHOR) qdsunsc@163.com, Wan, Xiaoyi¹ (AUTHOR), Li, Yanlong² (AUTHOR), Cui, Liping¹ (AUTHOR), Gan, Quan¹ (AUTHOR), Yang, Yunqin¹ (AUTHOR)
Source:	Chemical Engineering Science. Sep2026, Vol. 333, pN.PAG-N.PAG. 1p.
Subjects:	Fracture mechanics, Gas hydrates, Petroleum reservoirs, Heat transfer, Geothermal resources, Gas extraction, Gas seepage
Abstract:	[Display omitted] • The inclined fracture-assisted multi-gas joint production for hydrate is proposed. • Interlayer fractures with 45°∼90° angles effectively guide geothermal energy. • Increasing fracture width enhances dissociation ratio but reduces gas–water ratio. • Influence mechanism among interlayer seepage, heat transfer and hydrate dissociation. • Impact of fracture tip position on hydrate dissociation and energy utilization rates. To achieve commercial production of hydrate reservoirs, the utilization of underlying gas for multi-gas source joint production is a key development direction. But the hydrate dissociation ratio on long-term production is limited by the low permeability and low dissociation driving force. This work investigates the productivity and hydrate dissociation process of reservoirs produced by hydrate-layer horizontal wells combined with and without the assistance of interlayer fractures. Results show that all fractures can accelerate the upward movement of the underlying fluid that carrying geothermal energy, increasing the cumulative gas production by 3.96 to 4.9 times and the total hydrate dissociation ratio to reach 13.6% to 22.4%. Interlayer fractures with angles of 45° to 90° are more effective in guiding geothermal energy to promote hydrate dissociation. The temperature rise within these fractures occurs significantly earlier than that in the surrounding sediments. Among them, the interlayer fractures that extend the fracture tip to the top of the three-phase layer showed the highest performance in cumulative gas production, gas–water ratio and total volume of dissociated gas. Increasing fracture width and angle can enhance the dissociation ratio, cumulative gas production, and the interlayer gas–water seepage flow at the bottom of the hydrate layer. Meanwhile, the energy transferred from adjacent layers to the hydrate layer increases, but the percentage utilized for endothermic dissociation decreases. Comprehensively considering the law of interlayer seepage and heat transfer, and economic benefits, it is suggested that the tip of interlayer fracture should only extend to the top of the three-phase layer, providing a theoretical basis for future modification schemes for reservoirs containing underlying gas. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

Description
Abstract:	[Display omitted] • The inclined fracture-assisted multi-gas joint production for hydrate is proposed. • Interlayer fractures with 45°∼90° angles effectively guide geothermal energy. • Increasing fracture width enhances dissociation ratio but reduces gas–water ratio. • Influence mechanism among interlayer seepage, heat transfer and hydrate dissociation. • Impact of fracture tip position on hydrate dissociation and energy utilization rates. To achieve commercial production of hydrate reservoirs, the utilization of underlying gas for multi-gas source joint production is a key development direction. But the hydrate dissociation ratio on long-term production is limited by the low permeability and low dissociation driving force. This work investigates the productivity and hydrate dissociation process of reservoirs produced by hydrate-layer horizontal wells combined with and without the assistance of interlayer fractures. Results show that all fractures can accelerate the upward movement of the underlying fluid that carrying geothermal energy, increasing the cumulative gas production by 3.96 to 4.9 times and the total hydrate dissociation ratio to reach 13.6% to 22.4%. Interlayer fractures with angles of 45° to 90° are more effective in guiding geothermal energy to promote hydrate dissociation. The temperature rise within these fractures occurs significantly earlier than that in the surrounding sediments. Among them, the interlayer fractures that extend the fracture tip to the top of the three-phase layer showed the highest performance in cumulative gas production, gas–water ratio and total volume of dissociated gas. Increasing fracture width and angle can enhance the dissociation ratio, cumulative gas production, and the interlayer gas–water seepage flow at the bottom of the hydrate layer. Meanwhile, the energy transferred from adjacent layers to the hydrate layer increases, but the percentage utilized for endothermic dissociation decreases. Comprehensively considering the law of interlayer seepage and heat transfer, and economic benefits, it is suggested that the tip of interlayer fracture should only extend to the top of the three-phase layer, providing a theoretical basis for future modification schemes for reservoirs containing underlying gas. [ABSTRACT FROM AUTHOR]
ISSN:	00092509
DOI:	10.1016/j.ces.2026.124209