| 摘要: |
| 大量研究表明南海北部珠江口盆地是天然气水合物发育区，但是该盆地东部揭阳凹陷水合物研究较少。本文利用揭阳凹陷新采集三维地震资料，对该三维地震资料进行成像道集优化和叠前时间偏移处理，得到针对水合物的新处理地震数据体，并通过高精度网格层析反演得到层速度数据体。利用该数据开展叠后约束稀疏脉冲反演，获得含天然气水合物地层波阻抗异常，综合分析反演与地震属性识别水合物。从新处理地震资料看，该区域似海底反射（bottom simulation reflection，BSR）反射呈连续、不连续与地层斜交等特征，BSR发育在一个继承性小型水道上，且下部断裂和气烟囱发育。通过分析BSR特征及BSR上下地层的速度、波阻抗、振幅、频率、相干等属性异常，结合水合物成藏条件，发现了南海北部新的天然气水合物有利富集区，为该区域水合物勘探提供基础。 |
| 关键词: 天然气水合物 揭阳凹陷 地震反演 水合物成藏 |
| DOI：10.11693/hyhz20191100218 |
| 分类号:P618.13 |
| 基金项目:"十三五"国家重点研发计划项目子课题，2017YFC0307301-1号；国家高技术研究发展计划（863计划）课题，2013AA092601号。 |
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| SEISMIC ANOMALIES OF GAS HYDRATE-BEARING SEDIMENTS IN THE JIEYANG SAG, NORTHERN SLOPE OF SOUTH CHINA SEA |
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LI Jie1,2, HE Min1,2, YAN Cheng-Zhi1,2, LI Yuan-Ping1,2, JIN Jia-Peng3
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1.CNOOC China Limited, Shenzhen Branch, Shenzhen 518054, China;2.CNOOC Deepwater Development Ltd., Shenzhen 518054, China;3.Institute of Oeanology, Chinese Academy of Sciences, Qingdao 266071, China
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| Abstract: |
| A large number of studies show that the Zhujiang (Pearl) River Mouth Basin in the north of the South China Sea is a gas hydrate development area, but studies on the hydrate in the Jieyang Sag in the east of the basin are few. In this study, using the newly acquired three-dimensional seismic data of Jieyang Sag, the imaged gathers optimization and pre-stack time migration processing were carried out for the three-dimensional seismic data, and the interval velocity cube was obtained by high-resolution grid tomographic inversion. Using the data to perform post-stack constrained sparse spike inversion, the acoustic impedance anomaly of gas hydrate formation was acquired, and the hydrate was identified by comprehensive analysis of inversion and seismic attributes. According to the newly processed seismic data, BSR reflection in this area was characterized by continuity, discontinuity, and cross-bedding. BSR was developed on an inherited small channel, and faults and gas chimneys were developed below. Based on the analysis of the characteristics of BSR and the anomalies of velocity, wave impedance, amplitude, frequency, coherence, and other attributes of the upper and lower strata of BSR, combined with the conditions of hydrate accumulation, a new favorable gas hydrate accumulation area in the north of South China Sea was found, which provides the basis for hydrate exploration in this area. |
| Key words: gas hydrate Jieyang Sag seismic inversion gas hydrate accumulation |
