| 陆架边缘三角洲研究进展及实例分析 |
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| 引用本文： | 朱筱敏,葛家旺,赵宏超,袁立忠,刘军.陆架边缘三角洲研究进展及实例分析[J].沉积学报,2017,35(5):945-957. |
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| 作者姓名： | 朱筱敏 葛家旺 赵宏超 袁立忠 刘军 |
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| 作者单位： | 1.中国石油大学(北京)地球科学学院, 北京 102249; |
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| 基金项目： | 国家科技重大专项子项目，国家自然科学基金项目(41272133) National Science and Technology Major Project |
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| 摘 要： | 自上世纪90年代以来，发育在大陆架边缘的一种特殊类型的三角洲（shelf-edge delta），因其厚度大，分布面积广，储层物性好，常常与陆坡深水扇体伴生，成藏条件好等特点而引起了广泛关注，成为当前国际沉积学界研究的热点和油气勘探新领域。陆架边缘三角洲一般形成于相对海平面下降或低位时期，主要受控于物源供给、可容纳空间和气候变化，并受到陆坡构造活动影响；也可发育在高位时期，受到波浪与潮汐的影响。前人提出了利用陆架边缘迁移轨迹预测深水沉积和基于陆架斜坡发育模式预测深水沉积的模型，即强烈抬升的陆架边缘迁移轨迹、强烈加积的陆架斜坡发育模式，对应的深水区物质传输体系为泥质；水平—轻微下降的陆架边缘迁移轨迹、强烈前积的陆架斜坡发育模式，预示着大量砂体被搬运至深水区；轻微抬升的陆架边缘迁移轨迹、加积与前积的陆架斜坡发育模式，暗示深水沉积砂体发育介于上述二者陆架边缘迁移与深水扇预测模式之间。陆架边缘三角洲—深水扇规模砂体毗邻优质烃源岩，具备多种类型的油气运移通道，成藏条件良好，是油气勘探的有利领域。实例分析表明:渐新世珠海组沉积时期构造相对稳定，在古珠江充足的供源条件下，南海北坡珠江口盆地鹤山凹陷发育陆架边缘三角洲并伴随陆架不断向海迁移而不断进积，S型前积体不断向海迁移，并在晚期发育下切谷及大型盆底扇沉积。鹤山凹陷珠海组沉积时期发育水平—轻微下降的陆架边缘迁移轨迹，对应于强烈前积的陆架斜坡发育模式，在珠海组沉积晚期发育较大规模叠合连片深水扇富砂沉积体系，是研究区极好的潜在油气勘探目标。
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| 关 键 词： | 陆架边缘三角洲 深水扇 主控因素 预测模型 鹤山凹陷 南海北部 |
| 收稿时间： | 2017-05-16 |
Development of Shelf-edge Delta Researches and Typical Case Analyses |
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| ZHU XiaoMin,GE JiaWang,ZHAO HongChao,YUAN LiZhong,LIU Jun.Development of Shelf-edge Delta Researches and Typical Case Analyses[J].Acta Sedimentologica Sinica,2017,35(5):945-957. |
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| Authors: | ZHU XiaoMin GE JiaWang ZHAO HongChao YUAN LiZhong LIU Jun |
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| Institution: | 1.College of Geosciences, China University of Petroleum, Beijing 102249, China;2.Shengzhen Institute of CNOOC Limited, Shenzhen, Guangdong 518067, China |
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| Abstract: | Since last century nineties,a special marine delta named shelf-edge delta widely developed at the margin of the shelf has been an international interest and new field for petroleum exploration, which is commonly character-ized by thick-bedded sand-rich deposits, large-scaled distribution, high porosity and perfect petroleum accumulation conditions associated with marine slope or deep-water fan deposits. The shelf-edge delta is usually developed during the falling stage or low-stand stage of sea-level,influenced by the slope tectonic structures.However,it can also occur during the high-stand stage,comprehensively controlled by sediment supply,accommodation space and climate condi-tions,and sometimes of wave or tide influence. Previous studies have extensively indicated that the deepwater sedi-mentation prediction based on shelf-slope clinoform growth model is similar to the shelf edge trajectory migration motif. Steeply rising shelf-edge trajectories and dominantly aggradational stacking patterns are fronted by large-scale mass-transport systems,while, flat to slightly falling shelf-edge trajectories and progradational and downstepping stacking patterns are empirically related to large-scale submarine fan systems associated sand-rich gravity flows. Slightly rising shelf-edge trajectories and progradational and aggradational stacking patterns are associated with mixed sand/mud gravity flows and moderate-scale slope-sand deposits. Abundant examples have been identified that the sand-rich de-posits of shelf-edge delta and deep-water fan systems serve a perfect source-reservoir-capping condition, prove to be good petroleum exploration targets. A large-scale and thick-bedded Oligocene shelf-edge delta deposits are observed in the Heshan Depression of Pearl River Mouth basin, northern slope of the South China Sea, in response to the suffi-cient sediment supply from the ancient Pearl River with a slow tectonic subsidence. Associated with the migration of shelf edge,the sigmoid seismic progradations of shelf-edge delta are significantly seaward prograded. The occurrence of incised valley and large scale submarine fan systems during the late Oligocene times,together with observed seismic reflection geometries suggest the development of flat to slightly falling shelf-edge trajectories and progradational and downstepping stacking patterns in the Heshan Depression. The related thick-bedded submarine fan systems associated sand-rich deposits are important and potential strategic oil and gas exploration targets in the future. |
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| Keywords: | shelf-edge delta deep-water fan controlling factors predication model Heshan Depression Northern South China Sea |
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