摘要:基于千余口钻井资料剖析，结合野外剖面观测、地球化学特征及沉积物理模拟等资料的综合分析，对鄂尔多斯盆地东南部延安气田石炭系—二叠系的沉积体系及不同时期的沉积演化进行了研究。结果表明，研究区主要发育障壁海岸沉积、陆表海碳酸盐台地沉积、辫状河三角洲沉积、曲流河三角洲沉积和湖泊沉积，不同沉积体系的时空分布存在明显差异。受区域构造演化的控制，从石炭系—二叠系区内经历了由海及陆的沉积演化过程，本溪期与太原期发生大规模海侵，海相沉积占主导，发育障壁海岸—碳酸盐台地沉积；山西期，海水逐渐退出，区内进入海陆过渡相沉积，发育曲流河三角洲沉积；石盒子期至石千峰期，区内完全进入陆相沉积环境，受物源供给的影响，石盒子组和石千峰组早期均发育辫状河三角洲沉积，其余层段则以曲流河三角洲前缘沉积为主。
关键词: 鄂尔多斯盆地/
东南部/
延安气田/
石炭系/
二叠系/
沉积演化
Abstract:Based on the analysis of tens of thousands drilling cores, combined with the comprehensive analysis of outcrop observation, geochemistry characteristics and sedimentary physical simulation, this paper makes a study of sedimentary system and deposition evolution in different periods of Carboniferous and Permian. The results show that the main sedimentary systems in the study area include barrier coastal, carbonate platform, braided river delta, meandering river delta and lacustrine deposition, sedimentary systems exhibited diverse spatiotemporal distributions. Controlled by the regional tectonic evolution, the study area underwent the evolution process of alternating marine facies to continent facies during the Carboniferous-Permian period. A large-scale seawater invasion took place at the age of Benxi Formation and Taiyuan Formation, the marine sediments are dominant, barrier coastal and carbonate platform deposition were developed. At the age of Shanxi Formation, seawater receded gradually and the study area evolved into marine-continental transitional facies, meandering river delta deposition was developed. When came to the age of Shihezi and Shiqianfeng formations, the study area has evolved into continental facies completely, influenced by the supplement of provenance, braided river delta was developed in the early period of Shihezi and Shiqianfeng formations, while meandering river delta front deposition was developed in the other periods.
Key words:Ordos Basin/
Southeast/
Yan'an gas field/
Carboniferous/
Permian/
Deposition evolution
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