| 摘要: |
| 通过总结浅水三角洲沉积特征,结合库车坳陷克拉苏冲断带白垩系巴什基奇克组浅水三角洲的研究,对浅水三角洲特征及其分类方案进行探讨。结果表明:根据不同的供源体系可将浅水三角洲划分为浅水扇三角洲、浅水辫状河三角洲及浅水曲流河三角洲;浅水三角洲的发育需要稳定的构造背景、盆广坡缓、古水体浅、湖平面升降旋回变化、气候适宜、砂质底载荷河流供源充足等有利地质条件;浅水三角洲具有粒度粗、沉积水动力强的沉积特点,单砂体薄、复合砂体厚度大、分布面积广,发育分流河道、河口坝难以保留,垂向上相序不连续、缺乏传统三角洲三层式结构等特征。实例研究表明:库车坳陷巴什基奇克组属浅水辫状河三角洲,其成分成熟度较低、结构成熟度中等偏低,发育交错层理等强水动力沉积构造和间断正韵律,水下分流河道改道频繁、砂体纵横叠置、厚度大、延伸远,有利于构成岩性油气藏。 |
| 关键词: 浅水三角洲 沉积特征 形成条件 库车坳陷 白垩系巴什基奇克组 |
| DOI：10.3969/j.issn.1673-5005.2013.05.002 |
| 分类号:TE 121.3 〖HTH〗 |
| 基金项目:国家自然科学基金项目(41272133);国家“973”计划课题(2011CB201104);国家科技重大专项课题(2011ZX05001-002,1ZX05009-002,1ZX05025-005) |
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| Formation and development of shallow-water deltas in lacustrine basin and typical case analyses |
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ZHU Xiao-min, PAN Rong, ZHAO Dong-na, LIU Fen, WU Dong, LI Yang , WANG Rui
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(College of Geosciences in China University of Petroleum, Beijing 102249, China)
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| Abstract: |
| Based on the systematic analysis of sedimentary characteristics of shallow-water deltas, and in combination of a case study of the shallow-water deltas of the Lower Cretaceous Bashijiqike formation in Kuqa depression, the general classification of shallow-water deltas was discussed. According to different feeding system, shallow-water deltas can be divided into shallow-water fan-delta, shallow-water braided-delta and shallow-water meander-delta. The development of shallow-water deltas requires conditions such as a stable tectonic setting, a wide basin with gentle slope, shallow water, frequently varying lake levels, suitable climate, ample sandy river supplies and other favorable geological conditions. Shallow-water deltas are characteristics of coarse grain size deposited within the strong water dynamic conditions. Single delta is thin and widely spread while composite deltas cover a vast area with great thickness. Shallow-water deltas develop distributary channels but few mouth bars. Shallow-water deltas do not have continuous facies sequence in the vertical direction, and lack the three-layer structure of traditional deltas. Case study shows that the shallow-water braided delta of the Lower Cretaceous Bashijiqike formation in Kuqa depression has the following characteritics:low compositional maturity and low to medium textural maturity, cross bedding formed by strong hydrodynamic power, intermittent positive rhythm, and frequently diverted underwater distributary channels, channel sandbodies superimposed in vertical and horizontal direction with large thickness, and far extended distance. All of the characteristics are favorable to the formation of lithologic reservoirs. |
| Key words: shallow-water deltas depositional feature formation condition Kuqa depression the Cretaceous Bashijiqike formation |
