Abstract The stimulation of hydraulic fracturing on a combination of depressurization with thermal stimulation for natural gas hydrate (NGH) exploitation from challenging ocean hydrate reservoirs is investigated in this study. The influence of fracture permeability, well spacing on hydrate exploitation, and the enhancement effect of hydraulic fracturing on different well spacing are numerically investigated. The results show that the hydraulic fracturing has a significant improvement on hydrate exploitation performance, including hydrate decomposition behaviour, gas production behaviour, gas recovery ratio, and energy ratio. This improvement enhances with the increase of fracture permeability, but the corresponding rate of increase gradually decreases. Gas production performance is extremely sensitive to well spacing. An extremely low gas production volume, gas recovery ratio and energy ratio will be obtained when well spacing is excessive. The existence of fracture can increase the effective well spacing. After fracturing, the gas production performance of each well spacing are significantly improved and this improvement performs better with larger well spacing.

中文翻译：

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具有挑战性的海洋水合物储层减压与热刺激相结合的水力压裂增产效果评价

摘要 本研究研究了减压与热刺激相结合的水力压裂增产，用于从具有挑战性的海洋水合物储层中开采天然气水合物 (NGH)。数值研究了裂缝渗透率、井距对水合物开采的影响，以及水力压裂对不同井距的强化效果。结果表明，水力压裂对水合物的开采性能，包括水合物分解行为、产气行为、采气率和能量比有显着改善。这种改善随着裂缝渗透率的增加而增强，但相应的增加率逐渐减小。采气性能对井距极为敏感。井距过大，产气量、采气率和能量比都极低。裂缝的存在可以增加有效井距。压裂后，各井距产气性能显着提高，井距越大，这种改善效果越好。