鄂尔多斯盆地东南部上古生界层序地层格架及含气砂体沉积演化特征

发布时间：2018-12-25 17:15

【摘要】：鄂尔多斯盆地长期存在"南油北气"的固有认识,晚古生代早期砂体不发育与分布规律不清的认识,长期制约了盆地东南部天然气勘探开发的步伐。因此,加强盆地东南部上古生界煤系含气地层地质方面的研究、尤其是层序地层与储集砂体成因研究,对进一步增储上产具有重要理论与实践意义。作者采用Vail经典层序地层理论与方法,对鄂尔多斯盆地东南部上古生界进行层序地层研究:首先对层序界面进行识别,以岩性、旋回和沉积特征变化作为识别依据,并提出二级层序界面上下岩性组合变化巨大、二级界面之上叠置的低位砂厚度巨大的观点,共将本溪组—石盒子组划分为3个二级层序,11个三级层序;其次根据层序内部砂体堆积、迁移样式对体系域进行了划分。通过大量钻井的层序单元追踪对比与岩心精细描述,重点分析层序格架内主要含气层段本溪组、山西组及盒8段储集砂体的空间叠置关系,结合不同时期基准面旋回变化及其形成机制对其进行探讨,认为优势含气层段储集层中本2段具有障壁迁移、毯式连通,山2段具有低位控砂、面线连通,山1段具有侧向迁移、接触式连通,盒8段具有迁摆叠置、多向连通的特点。
[Abstract]:The inherent knowledge of "South oil-north gas" existed for a long time in the Ordos Basin, and the recognition that the sand bodies did not develop and the distribution law was unclear in the early Paleozoic, which restricted the pace of natural gas exploration and development in the southeastern part of the basin for a long time. Therefore, it is of great theoretical and practical significance to strengthen the geological study of the Upper Paleozoic gas bearing strata in the southeastern part of the basin, especially the formation of sequence stratigraphy and reservoir sand bodies. In this paper, the Vail classical sequence stratigraphy theory and method are used to study the Upper Paleozoic in the southeast of Ordos Basin. Firstly, the sequence interface is identified, and the lithology, cycle and sedimentary characteristics are used as the basis for the identification. The viewpoint that the upper and lower lithologic assemblages of the secondary sequence interface change greatly and the low sand thickness superimposed on the secondary interface is huge is put forward. Benxi formation-Shihezi formation is divided into 3 secondary sequences and 11 third order sequences. Secondly, the system tracts are divided according to the sandbody accumulation and migration patterns. Based on the tracing and correlation of a large number of well-drilled sequence units and the fine description of the cores, the spatial overlay relationships of the main gas bearing member Benxi formation, Shanxi formation and Ke 8 member reservoir sand bodies in the sequence framework are analyzed. Combined with the change of base-level cycle in different periods and its formation mechanism, it is considered that this 2 member of the dominant gas-bearing reservoir has barrier migration, blanket connectivity, low sand control and plane line connection. Shan 1 has lateral migration, contact connection, box 8 has the characteristics of pendulum superposition and multidirection connectivity.
【作者单位】：中国地质大学(北京)能源学院;陕西延长石油(集团)有限责任公司;
【基金】：国家自然科学基金项目(编号:41072084)资助~~
【分类号】：P618.13

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