| 摘要: |
| 陆相拗陷湖盆陡坡带具有坡度陡、构造活动强烈、物近源、多物源、相变快等特点。勘探实践表明,与拗陷湖盆陡坡带相关的各类砂体,由于具有良好的油源条件、储集条件和油气运移条件,是油气聚集成藏的极有利场所。鄂尔多斯盆地三叠纪时期为典型的内陆大型拗陷盆地,陇东地区三叠纪延长期时在西缘逆冲带的影响下处于陡坡带,该区有两种物质聚集模式,一是从长10-长7退积型三角洲模式,二是从长6-长1进积型三角洲模式。并且在盆地形成演化过程中,伴随着基准面的升降变化,不同相区、不同时期可容纳空间和沉积物供应之间的比值发生相应的变化,从而表现为不同的地层充填样式。 |
| 关键词: 拗陷湖盆|陡坡带|物质聚集|层序充填动力学|陇东地区 |
| DOI： |
| 附件 |
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| 基金项目:国家重点基础研究发展计划(973计划)项目(编号:2003CB214600) |
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| Sediment accumulation on the steep slope zone of the continental down-warped lacustrine basin and dynamics of sequence filling: An example from the Triassic Yanchang Formation in the Ordos Basin,eastern Gansu |
| NI Xin-feng, CHEN Hong-de, WEI Dong-xiao, ZHAO Jun-xing |
(1. Hangzhou Institute of Geology, PetroChina, Hangzhou 310023, Zhejiang, China;
2. Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, Sichuan, China) |
| Abstract: |
| The steep slope zone of a continental down-warped lacustrine basin tends to have the features of steep slope,intense tectonic movement,nearer provenance,multiple origins and sharp facies changes.The exploration in recent years has disclosed that all kinds of sandstone bodies associated with the steep slope zone of a down-warped lacustrine basin may be interpreted as most favourable places for oil and gas accumulation due to good conditions of source rocks,reservoir rocks and oil and gas migration.The Ordos Basin was once a typical large-scale continental down-warped lacustrine basin during the Triassic,and the eastern part of Gansu was in the steep slope zone under the influence of the western thrust zone during the Yanchangian of the Triassic.Two models for sediment accumulation are constructed for this steep slope zone: one for the Chang10-Chang7 retrogradational delta and another for the Chang6-Chang1 progradational delta.The accommodation space/sediment supply ratios have changed in different facies zones and periods in response to the base-level fluctuations during the formation and evolution of the basin,giving rise to distinct stratial filling patterns. |
| Key words: down-warped lacustrine basin|steep slope zone|sediment accumulation|dynamics of sequence filling|eastern Gansu |
