神狐深水海域天然气水合物成藏的气源条件

Gas Sources Condition of Gas Hydrate Formation in Shenhu Deep Water Sea Zone

为深入分析南海北部神狐深水海域天然气水合物形成的气源控制因素,以神狐海域天然气水合物调查区为重点研究对象,在基础调查资料和相关钻探成果的综合研究基础上,全面探讨了神狐海域天然气水合物成藏的气源供给条件。研究结果表明:(1)神狐海域浅层400～1 200 m以内具备良好的适合微生物成因甲烷气体生成条件,生物气生气潜力巨大;(2)深部古近系文昌组湖相和恩平组煤系两套成熟烃源岩,亦以生气为主,能够提供一定数量的热解气补充之;(3)深部成熟热解气通过纵向断层或底辟通道垂向运移至浅层海底,在浅部与微生物气一起侧向运移至天然气水合物稳定域内形成混合型天然气水合物藏。

To further study the gas source controlling factors of gas hydrate formation in Shenhu deep water zone of the northern in South China Sea,this paper focuses on the survey area of hydrate in Shenhu area,and analyzes the influence of various gas source supply conditions by the basic survey data and results of drilling in the area. The main results are as follows：（1）in the shallow area,about 400～1 200 m under the seabed,there are good conditions for biogenic gas formation and the potential Bio-gas source rocks,and it has great potential for the production of the biogenic methane gas;（2）in the deep area,the early Tertiary area,Wenchang Formation and Enping Formation are two main source rocks and can provide some thermogenic gas for gas hydrate formation;（3）Gas hydrate reservoir was formed in the deep areas,where deep thermogenic gas migrates upwards to shallow ground by faults or diapers,then,biogenic gas and thermogenic gas were enriched in the stability region of hydrate by lateral migration.