南海神狐海域天然气水合物试采成功后的思考

• 作者: 吴时国 王吉亮
• 来源期刊: 科学通报
• 年，卷（期）: 2018,（1）
• 所属期刊栏目: 观点
• 页码范围: 2-8
• 页数: 7页
• 语种: 中文
• DOI: 10.1360/N972017-00645

摘要

China has succeeded in gas extraction from fine-grained gas hydrate reservoir in Shenhu area,northern South China Sea.In March 2017,China Geological Survey drilled the first test well at the water depth of 1266 m.Steady gas flow was obtained continuously from the test well from May to July (60 d totally).The total volume of gas accumulated during this period reached up to 300000 m3,with an average of 5000 m3/d.The test well was later shut off by the operation team as 60 d greatly exceeded production schedule and the field trial accomplished all objectives.The success of this gas production trial demonstrates that gas hydrate hosted in fine-grained marine sediments can be exploited with current production technology.The success of the production test is based on a number of progresses made on the investigation and studying of gas hydrate in the northern South China Sea.The seismic indicators of gas hydrate,such as bottom simulating reflectors (BSRs),were first identified in the northern South China Sea in the late 1990s.Subsequently,four areas,namely Dongsha,Shenhu,Xisha and Qiongdongnan,were selected as the main potential targets for gas hydrate exploration and exploitation according to geologic and geophysical investigations.From 2007 to 2016,four gas hydrate drilling expeditions were conducted in the northern South China Sea.These expeditions confirm the presence of gas hydrate in Shenhu and Dongsha area.They also show that gas hydrate bearing sediments in Shenhu area have larger thickness,higher saturation than those in Dongsha area.Besides,these sediments in Shenhu area exhibit a good lateral continuity,which facilitate gas hydrate exploitation.The above characteristics of gas hydrate reservoir make Shenhu area become the first gas-hydrate production test target in the northern South China Sea.A range of difficulties have been encountered in the production test of Shenhu area compared to the field production trial of Nankai Trough in Japan.First,while gas-hydrate test site in Nankai Trough is located at a water depth of 600 m,the site in Shenhu area is located at a water depth of more than 1200 m,which increases operation risk as water depth rises.Furthermore,gas hydrates in Shenhu area are buried at a depth of 100-200 m below seafloor,which is shallower than that in Nankai Trough (276-337 m below seafloor).Such a shallow depth results in weak compaction and loose sediments,and therefore increases the possibility of seafloor instability during production operations.More importantly,gas hydrate reservoirs in Nankai Trough,which have an average saturation of 70％,is much more concentrated than that in Shenhu area.The hosted sediment is shale/silt in Shenhu area,which results in low permeability,while it is sand in Nankai Trough.In brief,the quality of fine-grained gas hydrate reservoir in Shenhu area is lower than that of sand-prone gas hydrate reservoir in Nankai Trough.The production test has succeeded in overcoming the above difficulties and realized 60 d's continuous and steady production.Therefore,the success of production trial in Shenhu area marks a great progress in the gas hydrate exploitation.Despite major advances in gas hydrate exploitation in recent years,there is still a long way to go in realizing the commercial production of marine gas hydrate.In order to utilize gas hydrate economically,safely and environment-friendly,more work needs to be done on the improvement of gas-hydrate accumulation theory and exploration technique,as well as the updating of development techniques and environment protection methods during exploitation.

作者信息

序号	姓名	单位	发文数	被引次数	H指数	G指数
1	吴时国	中国科学院深海科学与工程研究所	113	2225	26.0	43.0
2	王吉亮	中国科学院深海科学与工程研究所	8	25	2.0	5.0