Gas recovery enhancement from methane hydrate reservoir in the Nankai Trough using vertical wells
Gas recovery enhancement from methane hydrate reservoir in the Nankai Trough using vertical wells
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DOI：
10.1016/j.energy.2018.10.155
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发表时间：
2019-01
期刊：
影响因子：
9
通讯作者：
Tao Yu;G. Guan;A. Abudula;A. Yoshida;Dayong Wang;Yongchen Song
中科院分区：
文献类型：
--
作者：
Tao Yu;G. Guan;A. Abudula;A. Yoshida;Dayong Wang;Yongchen Song
2013/2017年日本南海海槽和2017年中国神湖地区海上甲烷水合物生产试验向世界展示了降压生产海洋甲烷水合物的可能性和可行性。然而，相对较低的产气率仍然是经济利用的关键瓶颈之一。本研究以南海海槽为研究对象，以直威尔斯井提高甲烷水合物气藏采收率为目标。提出了传统的单直井系统和新型的双直井系统，并对这两种系统分别采用积极降压和提高渗透率的特殊开采策略进行了有效性验证。15年模拟结果表明，储层中以粉砂为主的中低渗层是提高采收率的关键，对于单直井系统而言，提高该层渗透率比积极降压更为可靠和可行。而双直井系统由于两井的协同作用，其平均产气量（9.5 × 103 m3/d）明显高于单直井系统，可提高一个数量级（7.9 × 104 m3/d）。若与积极降压相结合，平均产气量可进一步提高一个数量级（达到3.4 × 105 m ~ 3/d）。
The 2013/2017 Nankai Trough (Japan) and 2017 Shenhu Area (China) offshore methane hydrate production tests showed the world the possibility and feasibility of the oceanic methane hydrate production by depressurization. However, the relatively low gas production rate still remained as one of the critical bottlenecks for the economical utilization. This study chose the Nankai Trough as a target area, and aimed at the gas recovery enhancement from the methane hydrate reservoir using vertical wells. A traditional single-vertical-well system and a new dual-vertical-well system were proposed, and special production strategies of the aggressive depressurization and permeability improvement were applied to these two systems for the effectiveness verification. Based on the 15-year simulation results, it was found that the middle low-permeability silt-dominated layers in the reservoir held the key to the gas recovery enhancement, and for the single-vertical-well system, the permeability improvement in this sublayer seemed more reliable and feasible than the aggressive depressurization. On the other hand, the dual-vertical-well system significantly exceeded the single-vertical-well system due to the synergistic effect of the two wellbores, and could raise the average gas production rate (9.5 × 103m3/day) by one order of magnitude (to 7.9 × 104m3/day). Moreover, if this new system was combined with the aggressive depressurization, the average gas production rate could be further raised by one order of magnitude (to 3.4 × 105m3/day).